This is a copy of the Notes and references in the book for easy access to the web links.
1 The ‘Stern review report on the economics of climate change’ (2006), https://tinyurl.com/stern-review2006. This was a landmark report commissioned by Tony Blair and Gordon Brown and led by Sir Nicholas Stern, one of the UK’s most eminent economists. It made the case that it wasn’t just good for the planet to deal with climate change – as the scientists, environmentalists and tree huggers had been saying for years – but it was actually a good idea financially, too. Suddenly, climate change was on the map and even corporate executives were allowed to mention it without sidelining their careers.
2 How can that possibly be when we have had so many global agreements and national targets and almost everyone reading this book will have done at least something at some time to cut their own carbon? Surely it adds up to something?!? See pp. 17 and 166 for a quick explanation, but for the full details you’ll have to take a look at one of my other books, There Is No Planet B: A Handbook for the Make Or Break Years (Cambridge University Press, 2021).
3 Intergovernmental Panel on Climate Change (IPCC, 2018), ‘Special report: global warming of 1.5°C’, www.ipcc.ch/sr15/
A brief guide to carbon footprints
1 Carbon Footprinting: An Introduction for Organisations, published by the UK’s Carbon Trust (2007), defined (on p.1) a carbon footprint in a similar way to me, but goes on to describe ‘basic carbon footprints’ on p.4. These are toe-prints rather than rough estimates of footprints, https://tinyurl.com/carbon-trust2007
2 Intergovernmental Panel on Climate Change (IPCC, 2018),‘Special report: global warming of 1.5°C’, www.ipcc.ch/sr15/
Less than 10 grams
1 Based on 142 litres per person per day, which is about average in the UK according to the Energy Saving Trust 2013 report ‘At home with water’, https://tinyurl.com/energysavingtrust2013
2 18kg CO2e per person works out to a UK annual tap water footprint of around 1.2 million tonnes CO2e. This is around 0.15 per cent of the total UK footprint of 800 million tonnes CO2e.
3 Based on figures for the carbon intensity of UK water supply and treatment by the UK government’s Department for Business, Energy and Industrial Strategy (BEIS). The full set of emission factors can be downloaded from Defra (2019), ‘Guidelines to Defra’s GHG conversion factors for company reporting’, https://tinyurl.com/beis-emission-factors
3 Based on figures for the carbon intensity of UK water supply and treatment: Defra (2019), ‘Guidelines to Defra’s GHG conversion factors for company reporting’, www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019
4 These estimates include the emissions embodied in the device, the electricity used to run it (assuming UK electricity) and electricity use in the networks, data centres and by the WiFi router. They are based on an iPhone 11 with 128GB that is kept for two years (see Using a smartphone, p.116) and a 13-inch MacBook Pro with 128GB storage that is kept for four years (see A Computer (and using it), p.129) that are connected to WiFi. Doing a search over mobile networks has a lower footprint, because it does not require a WiFi router; it comes to 0.11g CO2e per minute for the internet, compared to 0.4g CO2e per minute for WiFi. For the spam email, I’m assuming that it’s sent to so many people that the footprint of the device it’s written on is negligible and that nobody reads them, so it’s just the footprint of the transmission, assuming it takes 5 seconds in networks and data centres to transmit the email.
5 According to an estimate by Radicati (2018), there were 3.93 billion email users in 2019 and 294 billion emails were sent every day: Radicati (2018). ‘Email market, 2018–2022’, https://tinyurl.com/radicati2018. Statista estimate that 55 per cent of all emails in 2018 were spam, https://tinyurl.com/statista-spam
6 Assuming all emails were read on an iPhone 11. I have used a global average electricity factor for the use phase of the iPhone and WiFi router.
7 Based on a footprint of 0.05g CO2e per spam email (assuming a global average electricity factor for the use phase of the iPhone and WiFi router) and 59 trillion spam emails per year. That’s based on 55 per cent of all emails being spam emails (see previous note).
8 See note 4 above.
9 Hölzle, U. (2009), ‘Powering a Google search’, 11 January, https://tinyurl.com/powering-google. Google used an electricity intensity of 0.67kg CO2e per kWh back in 2009; today, global average electricity has decarbonised a bit to 0.63kg CO2e per kWh, so the footprint of one search has decreased from 0.2g to 0.19g – not much. But, if we assume Google’s data centres are twice as efficient today as they were in 2009, the footprint at Google’s end is just 0.09g.
10 According to the website Internet Live Stats, https://tinyurl.com/google-search-stats.
11 The figures are basedon two iPhones being used for 30 seconds each and transmission taking place for 5 seconds. They include the footprint of manufacturing and transporting an iPhone 11 to the user and the emissions from the electricity used to power the phone (see Using a smartphone,p.116), ca. 0.75g CO2e. They also include emissions from the electricity used in the mobile networks that transmit the text, at 2 watts according to Jens Malmodin, Senior Specialist at Ericsson and an expert in the energy and carbon footprint of networks. For 5-second transmission, assuming the text is sent within the UK using a carbon intensity of the local grid of 0.34kg CO2e per kWh, that’s 0.001g CO2e. Sending a message online through an app like WhatsApp has a higher carbon footprint because it requires around 5 watts in networks that can carry mobile data and 5 watts in data centres too, according to Ericsson – Ericsson (2020), ‘A quick guide to your digital carbon footprint – deconstructing Information and communication technology’s carbon emissions’, https://tinyurl.com/ericsson2020. And specifically their background report: https://tinyurl.com/ericsson2020-background. So that’s 0.009g CO2e for the transmission. But, because the device plays the biggest part in the footprint of sending a message, it scarcely matters how the message is transmitted.
12 World Economic Forum (2019), ‘Why big data keeps getting bigger’, https://tinyurl.com/weforum2019. This source estimates 18,100,000 texts being sent per minute in 2019, which is 9520 billion per year.
13 Ofcom reports that there were 79.49 million mobile subscribers for mobile handsets in 2018 in the UK and 73.84 billion outgoing SMS and MMS sent over mobile networks; Ofcom (2019), ‘Communications market report 2019’, https://tinyurl.com/comms-market-report. Marketing company SimpleText reports that Americans sent 15 texts per day, based on Zipwhip’s ‘State of texting report 2019’, https://tinyurl.com/texting-stats.
14 Plastics Europe’s Association of Plastic Manufacturers. Eco-profiles showing emissions from production of a wide variety of plastics are available from https://tinyurl.com/plasticseurope
15 Berners-Lee, M. (2019), There Is No Planet B (Cambridge University Press). See the chapter ‘How much plastic is there in the world?’ (1st ed., p. 55).
16 Ten seconds of drying at 1.6 kW equals about 0.003 of a kWh. The emissions from UK electricity are 0.339 kWh, so a Dyson Airblade is roughly 2g CO₂e. Using the calculation for the 6 kW hand dryer for 15 seconds gives us 0.033 of a kWh, which equals 11g CO₂e.
17 I am assuming that this low-grade paper comes in at just 1kg CO2e per kilo.
10 grams to 100 grams
1 The UK government’s Department for Business, Energy and Industrial Strategy (BEIS) give a figure of 1000kg CO2e per tonne of mixed paper in landfill. The full set of Defra BEIS emission conversion factors for (2019), which can be downloaded format: https://tinyurl.com/beis-emission-factors-2019
2 For the number up to the farm gate, I’ve used a 2008 report by the UK government’s Department for Environment, Food and Rural Affairs (Defra) (2008), ‘Final report for Defra project FO0103: comparative life cycle assessment of food commodities procured for UK consumption through a diversity of supply chains’, https://tinyurl.com/defra-fruit. I have then added on the processing and transport number using data from our work with Booths Supermarket: Berners-Lee, M., Moss, J., and Hoolahan, C. (2014). ‘The greenhouse gas footprint of Booths’. Small World Consulting, https://tinyurl.com/booths-footprint. Apple weight is assumed to be 112g. www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019 gives a figure of 1000kg CO2e per tonne of mixed paper in landfill.
3 Saunders, C., Barber, A., and Taylor, G. (2006) Food miles – comparative energy/emissions performance of New Zealand’s agriculture industry. Research Report no. 285, Lincoln, New Zealand: Lincoln University, https://tinyurl.com/saunders2006
4 Blanke, M., and Burdick, B. (2005), ‘Food (miles) for thought-energy balance for locally-grown versus imported apple fruit’. Environmental Science and Pollution Research, 12(3), 125–127. Referenced in Defra (2006), ‘Environmental impacts of food production and consumption’, https://tinyurl.com/defra-food, p. 47.
5 For the energy requirement, I’ve used the model laid out by David J.C. MacKay in the technical chapter at the back of his 2008 book Sustainable Energy – Without the Hot Air, which can be downloaded for free from www.withouthotair.com/. I’ve added the effect of hills. Onto this I’ve added the embodied carbon in the battery based on 190 Wh per kg of battery and 1000 charge cycles over its lifetime (data from Bosch).
6 Estimates for the embodied carbon per kWh of battery vary, and depend especially on the carbon intensity of the energy used to manufacture them. I’ve taken a fairly central figure of 100kg CO2e per kWh of battery capacity based on a literature review carried out by Carbon Brief: Hausfather, Z. (2019, May 13), ‘Factcheck: how electric vehicles help to tackle climate change’. Carbon Brief, https://tinyurl.com/hausfather2019. So that is 30g CO2e of embodied carbon in the battery per kWh of energy transmitted to your bike. Based on my model (see previous note), you need 15 Wh per mile if you weigh 80kg (with the bike), travel at 12 mph with five stops and 20m of climbing per mile. That comes to roughly 0.5g CO2e per mile for the battery.
7 Peace, R. (2019), ‘A guide to e-bike batteries’, We Are Cycling UK, 15 February. Cycling UK, https://tinyurl.com/e-bikes
8 For my calculations, I have used the exhaust emissions from the UK government’s Department for Business, Energy and Industrial Strategy (BEIS) and added on the supply chain emissions and embodied emissions for the petrol- and diesel-powered buses. For the electric bus, I have used BYD-ADL Enviro200EV as an example, which has a capacity of 90 people and uses roughly 1.34 kWh per mile. Multiplying the UK electricity figure of 0.34kg CO₂e by 1.34 kWh per mile gives a number of around 5g per passenger mile. I’ve worked out the embodied emissions to be a further 1g per passenger mile to get the final number of 6g. The full set of emission factors can be downloaded from the BEIS website, https://tinyurl.com/beis-emission-factors
9 Public Health England (2014), ‘Estimating local mortality burdens associated with particulate air pollution’, https://tinyurl.com/deathsdiesel, and Royal College of Physicians (2016), ‘Every breath we take: the lifelong impact of air pollution’, https://tinyurl.com/pollutiondiesel
10 In our input–output model of the greenhouse gas footprint of UK industries, sports goods typically have a carbon intensity of around 210g per £1 worth of goods at retail prices. If we make the very broad assumption that cycling goods are typical of this, and if we say that Her Majesty’s Revenue and Customs (HMRC) is being roughly fair to reimburse you at 20p per mile for business travel on a bike, then we would need to add about 42g CO2e per mile to take account of the wear and tear on your bike, your waterproofs, lights, helmet and so on. However, there are so many variables that I have gone for a range of 10–100g.
Actually, as someone who is frequently cycling between offices and train stations trying to keep jacket, tie and laptop dry, I suspect that HMRC has underestimated it and should be paying out the full 40p per mile that they allow for car users. (This would also provide a beneficial incentive.)
11 Direct emissions from fuel and electricity generation and supply come from the full set of 2019 Defra emission conversion factors (2019), which can be downloaded from the UK government’s Department for Business, Energy and Industrial Strategy (BEIS) web site: https://tinyurl.com/beis-emission-factors-2019. Supply chains and infrastructure are estimates made from my input–output model.
12 David J.C. MacKay lays out the maths nicely in Sustainable Energy – Without the Hot Air (2009), published by UIT Cambridge Ltd and available as a free download from www.withouthotair.com
13 Kemp, R. (2007), ‘Traction energy metrics’. Rail Safety & Standards Board, London.
14 The sums: a 5-square-metre doorway, fully open for 15 seconds, wind speed through the door of 1m per second, temperature difference of 15°C, heat capacity of air 1.2 kilojoules per cubic metre, heat supplied by gas at 0.22kg CO2e per kWh.
15 BREEAM (Building Research Establishment Environmental Assessment Method) is a sustainability assessment method for infrastructure projects and buildings. See www.breeam.com. I understand that the BRE has since improved its energy efficiency criteria somewhat. The sums here are based on a temperature difference of 15°C (typical for winter) and a wind speed of just 2.5 mph flushing warm air out of the building.
16 Quick, D. (2008), ‘Revolving door generates its own power’, 12 December, https://tinyurl.com/rotating-doors
100 grams to 500 grams
1 For the footprint for bananas and oranges, I’ve updated the numbers from a piece of work I was involved in a few years ago: Hoolahan, C., Berners-Lee, M., McKinstry-West, J., and Hewitt, C.N. (2013), ‘Mitigating the greenhouse gas emissions embodied in food through realistic consumer choices’. Energy Policy,63, 1065–1074, https://tinyurl.com/hoolahan2013
2 There is more on this on the website of the non-profit Banana Link: www.bananalink.org.uk
For a critical and pessimistic look at the future of bananas in our lives, see also Koeppel, D. (2008), ‘Yes, we will have no bananas’. New York Times, 18 June,https://tinyurl.com/koeppel2008
3 The charity Waste & Resources Action Programme (WRAP) estimates that people in the UK waste 22 per cent of the food they purchase: WRAP (2020), ‘Food surplus and waste in the UK – key facts’, https://wrap.org.uk/resources/report/food-surplus-and-waste-uk-key-facts#download-file (this link has been updated for the online version of the notes and references).
4 The number for disposable nappies comes from: Cordella, M., Bauer, I., Lehmann, A., Schulz, M., and Wolf, O. (2015), ‘Evolution of disposable baby diapers in Europe: life cycle assessment of environmental impacts and identification of key areas of improvement’. Journal of Cleaner Production, 95, 322–331, https://tinyurl.com/cordella2015
5 The study I’ve used for reusable nappies is Aumônier, S., Collins, M., and Garrett, P. (2008), An updated lifecycle assessment study for disposable and reusable nappies, Science Report no. SC010018/SR2, UK Environment Agency, https://tinyurl.com/aumonier2008. Since the first edition, I’ve calculated that washing at 60°C and drying on the line is now 35 per cent less carbon intensive than it was 10 years ago, and washing at 90°C and tumble drying is 42 per cent less carbon intensive, due to the UK electricity mix being a lot better than it used to be. I have factored this in to get the new numbers.
6 Hoolahan, C., Berners-Lee, M., McKinstry-West, J., and Hewitt, C.N. (2013). ‘Mitigating the greenhouse gas emissions embodied in food through realistic consumer choices’. Energy Policy, 63, 1065–1074, https://tinyurl.com/hoolahan2013
7 Figures include use phase electricity assuming the device is used in the UK, a share of the carbon embodied in the production and transport of the device (assuming a lifetime of four years), a share of the emissions from standby and the electricity used in the transmission of 1 hour of BBC content, and a share of the embodied footprint of the set-top box (for watching on a TV) or WiFi router (for watching on a laptop). The transmission includes use phase emissions from playout and coding and multiplexing, networks, satellites, data centre storage, access network equipment in home (such as set-top boxes and Wi-Fi routers) and personal video recorders.
I allocated standby and embodied emissions based on 4 hours and 11 minutes viewing per day. Ofcom estimates that ‘In 2018 individuals watched a total of 4 hours 54 minutes of audio-visual content, per person per day, across all devices.’ This includes 26 minutes for subscription-video-on-demand (such as Netflix or Amazon Prime), Ofcom (2019), ‘Media nations 2019: Interactive report’, https://tinyurl.com/ofcom-media-nations.
Assuming that 80 per cent of Netflix and co are viewed on a TV, that’s a total of 4 hours and 11 minutes of video content viewed on TVs per day by the average UK adult.
All the data on in-use and standby power consumption of the CRT, LED-backlit LCD and plasma TV come from Ireland’s Electricity Supply Board (2009) and for the 55-inch LED TVs from LG, https://tinyurl.com/lg-55-led-TV.
For calculating the carbon footprint, power consumption per hour was multiplied by my own figure for the carbon intensity of UK electricity with 0.34kg CO2e per kWh in 2019 (see A unit of electricity, p.51). When allocating a share of standby to per-hour figures, I assumed a standby power consumption of 0.32 watts for the 13-inch MacBook Pro, 0.5 watts for the 55-inch LED TV and 3 watts for the older TVs and 0.32 watts for the 13-inch MacBook Pro.
Embodied carbon estimates for the 32-inch LED-backlit LCD come from Huulgaard, R.D., Dalgaard, R., and Merciai, S. (2013), ‘Ecodesign requirements for televisions—is energy consumption in the use phase the only relevant requirement?’ International Journal of Life Cycle Assessment, 18(5), 1098–1105, https://tinyurl.com/huulgaard2013
For the 28-inch CRT screen, the embodied carbon is based on estimates for a 25-inch CRT TV by Feng, C., and Ma, X.Q. (2009), ‘The energy consumption and environmental impacts of a color TV set in China’. Journal of Cleaner Production, 17(1), 13–25, https://tinyurl.com/feng-ma2009
The embodied carbon footprint of the 55-inch LED TV comes from the report ‘Lean ICT’ (2018) by the French thinktank The Shift Project, based on Samsung manufacturer’s data: The Shift Project (2019), ‘Lean ICT: for a sober digital’, https://tinyurl.com/shiftproject2019
The figure for the 42-inch plasma TV comes from Stobbe, L. (2007), ‘EuP preparatory studies “televisions” (lot 5): final report’, Fraunhofer IZM, https://tinyurl.com/stobbe2007
For the 13-inch MacBook Pro, the embodied carbon estimates come from Apple’s Life Cycle Analysis report for the 1.4 GHz Quad-Core processor with 128GB storage model introduced in July 2019: https://www.apple.com/environment/pdf/products/notebooks/13-inch_MacBookPro_PER_June2019.pdf (this link has been updated for the online version of the notes and references).
For electricity consumption, I used a UK electricity intensity of 0.34 kgCO2e per kWh and information on power use from Apple, https://tinyurl.com/macbook-13-specs
I have adjusted the embodied emissions of TVs and MacBook upward for the 40 per cent truncation error that’s common for the manufacture of ICT based on my own research. The carbon footprint of transmission of TV content comes from a recent study by Schien et al.: Schien, D., Shabajee, P., Chandaria, J., Williams, D., and Preist, C. (2020), ‘BBC R&D White Paper 372: Using behavioural data to assess the environmental impact of electricity consumption of alternate television service distribution platforms’.
8 I’m assuming that you keep your TV for four years. If you keep your TV longer, this would spread out the total embodied carbon footprint of 735kg more.
9 Schien, D., Shabajee, P., Chandaria, J., Williams, D., and Preist, C. (2020), ‘BBC R&D White paper 372: Using behavioural data to assess the environmental impact of electricity consumption of alternate television service distribution platforms.’
This study of the carbon footprint of the BBC, based on 2016 data, includes use phase emissions from playout and coding and multiplexing, networks, satellites, data centre storage, access network equipment in the home and the viewing device that is typical for each transmission method. Their estimates exclude the embodied emissions in the network and data centre infrastructure. They estimate 0.07 kWh for digital terrestrial TV, 0.17kWh for satellite TV and 0.18 kWh for cable TV and BBC iPlayer. I have used a UK electricity factor of 0.34 kg CO2e per kWh and subtracted their estimate for the share of the viewing device to arrive at an estimate of emissions per hour for the transmission alone.
10 According to Apple, their TV 4K and Siri Remote 32GB set-top box model has an embodied footprint of 40kg CO2e (including manufacture and transport), https://www.apple.com/environment/pdf/products/appletv/Apple_TV_4K_PER_sept2017.pdf (this link has been updated for the online version of the notes and references).
Adjusted for a truncation error of 40 per cent, that’s 67kg CO2e. Apple assume a lifetime of four years, so that’s 16.7kg CO2e per year and 11g per hour if I assume an average use per day of 4 hours and 11 minutes.
11 BAFTA’s Albert Project estimates the average carbon footprint of an hour’s worth of TV content was 13.5 tonnes of CO2e in 2017 (Albert Annual Report 2018; note that this does not include other greenhouse gases and is not per person but total emissions independent of the number of viewers). This includes electricity used in studios, heating of offices, transport, accommodation, catering, materials used on set and waste. The footprint is highest for dramas and lowest for sports, and across all programme types, people transport plays the biggest role. For 2018, BAFTA estimate the average footprint of 1 hour’s TV content is 9.2 tonnes CO2 (personal communication with William Bourns at BAFTA).
12 The 13-inch MacBook Pro 1.4 GHz Quad-Core processor with 128GB storage has an embodied footprint of 326kg CO2e compared to 735kg for the 55-inch LED and its electricity consumption per hour has a footprint of only 2g compared to 30g for the 55-inch LED, assuming the laptop Is used 5 hours a day and the TV the average 4 hours and 11 minutes. This is one of the lowest-carbon laptops; models of the same line but with bigger internal storage use slightly more carbon and larger laptops like the 16-inch MacBook Pro 2.3 GHz 8-core processor with 1TB storage have an embodied footprint twice as high at 620kg CO2e and a much higher hourly carbon footprint for electricity of 14g, https://tinyurl.com/apple-16-macbook-pro
13 Schien et al. (2020) – see note 9 above.
14 I assume that a WiFi router has about the same embodied footprint as a set-top box, but that you share it with one other person, so it’s 5 g CO2e per hour.
15 I spoke to several experts to bottom out this entry. Chris Preist, Professor of Sustainability and Computer Systems at the University of Bristol, believes that higher resolution images do not result in proportionally higher quantities of data being downloaded, because of the impact of compression algorithms.
Jens Malmodin, Senior Specialist at Ericsson and an expert in the energy and carbon footprint of networks, thinks that 4G and 5G mobile networks are more efficient than fixed access networks (on which Wi-Fi relies), because their energy use scales with the amount of data being transferred. But from 10 MB per second (MBps) upwards, fixed networks are more efficient than mobile data. Netflix recommends 3 MBps for SD, 5 MBps for HD and 25 MBps for UHD, ttps://tinyurl.com/netflix-data
16 Sandvine estimates that Netflix accounts for 12.6 per cent of worldwide downstream volume, Sandvine (2019), ‘Netflix falls to second place in global internet traffic share as other streaming services grow’, 12 September, https://www.sandvine.com/hubfs/Sandvine_Redesign_2019/Downloads/Internet%20Phenomena/Internet%20Phenomena%20Report%20Q32019%2020190910.pdf (this link has been updated for the online version of the notes and references).
According to Sandvine (2019), video as a whole accounts for 61 per cent of downstream traffic and 22 per cent of upstream traffic globally in 2018, Sandvine (2019), ‘Global internet phenomena Report’, https://tinyurl.com/sandvine2019
The popularity of video streaming can drive expansion of the underlying internet infrastructure, which can in turn enable more data-intensive activities and thus lead to further growth in infrastructure and thus emissions, according to Preist et al. (2016): Preist, C., Schien, D., and Blevis, E. (2016), ‘Understanding and mitigating the effects of device and cloud service design decisions on the environmental footprint of digital infrastructure’. Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems, 1324–1337, https://tinyurl.com/preist2016
17 Schien et al. report that cable or satellite set -top boxes have a power consumption of 20 watts when in active standby and 10 to 15 watts in passive standby. Left on standby an average amount of 19 hours 49 minutes, that’s 49kg CO2e per year for active standby or 25–37kg CO2e for passive standby. Wi-Fi routers for video streaming also have a high standby. They use around 10 watts and don’t even have a standby. Over the course of one year, they use around 30kg CO2e in electricity from being on all the time: Schien, D., Shabajee, P., Chandaria, J., Williams, D., and Preist, C. (2020), ‘BBC R&D White Paper 372: Using behavioural data to assess the environmental impact of electricity consumption of alternate television service distribution platforms’, https://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP372.pdf (this link has been updated for the online version of the notes and references).
18 Based on UK electricity at 0.34 kg CO2e and gas at 0.225kg CO2e per kWh. Both figures are based on those supplied by BEIS (2019), https://tinyurl.com/beis-emission-factors-2019), but are adjusted to take account of power station supply chains and distribution. The cost of electricity is taken as 16p per kWh.
19 A couple of months ago, Claire Perry MP told radio listeners that the UK gets 32 per cent of our energy from renewables. Actually we get 32 per cent of only our electricity from renewables. The difference in the two statements is huge. The later translates to the UK sourcing something like 5 per cent of our total energy consumption from renewables, which is currently the case. I wasn’t the only one to pull her up on this, but I never saw an effort made to correct this misinformation to those who had heard her original false statement. If we are ever going to get on top of climate change, we are going to need to ensure politicians get better at honouring the truth. Much more on this in my other book, There Is No Planet B.
20 Confederation of Paper Industries (2006), ‘UK paper making industries statistical facts sheet’, Alsema, E.A. (2001), ICARUS 4: sector study for the paper and board industry and the graphical industry, Utrecht Centre for Energy Research.
21 Based on figures for the carbon intensity of mixed paper to landfill from the UK government’s Department for Business, Energy and Industrial Strategy (BEIS) conversion factors for 2019, https://tinyurl.com/beis-emission-factors-2019
23 It is already using more energy on Bitcoin mining than on powering all its households: Baraniuk, C. (2018), ‘Bitcoin energy use in Iceland set to overtake homes, says local firm’, 12 February. BBC, https://tinyurl.com/baraniuk2018
24 All the numbers on waste impacts come from the UK government’s Department for Business, Energy and Industrial Strategy (BEIS) 2019 conversion factors: BEIS (2019), ‘Greenhouse gas reporting: conversion factors 2019’, https://tinyurl.com/beis-emission-factors-2019
Conversion factors for virgin and recycled paper came from Confederation of Paper Industries (2006), UK paper making industries statistical fact sheet.
Environmental Defence Fund’s report (1995), ‘Energy, air emissions, solid waste outputs, waterborne wastes and water use associated with component activities of three methods for managing newsprint’, provided a sense of, and some figures for, transport and printing impacts. Added together, this gives a calculation of 1.5kg CO2e per kg for recycling a newspaper and 3.8kg CO2e per kg for sending it to landfill. It should also be noted that, when we weighed the weekly papers in the office, we found that they were a bit lighter than they were 10 years ago, hence the slightly smaller footprint of each paper. I’m not entirely sure why this is, but it could be down to each individual sheet being slightly thinner and/or smaller, each complete paper containing fewer pages, or there being fewer supplements (or a combination of the three).
25 Jern, M. (2018), ‘How many people consume bottled water globally?’, 29 October. TAPP Water, https://tinyurl.com/jern2018
26 The water itself is just 30g CO2e per 500ml, according to bespoke work done by Small World Consulting with Booths Supermarket,: Berners-Lee, M., Moss, J., and Hoolahan, C. (2014), ‘The greenhouse gas footprint of Booths’. Small World Consulting, https://tinyurl.com/booths-footprint.
The carbon intensity of PET, from which bottles are typically made, is 4.1 kg CO2e per kilo (see 1kg of plastic, p.98, for more details). The bottles I have weighed average around 50g per litre of capacity, which is around 103g CO2e per 500ml plastic bottle. Short-distance road transport has a footprint of 25g CO2e per bottle, whereas long-distance road transport is 101g CO2e.
27 In 2019, London installed 50 fountains around the city. This is a small start, at least. Greater London Authority (2019), ‘Mayor reveals locations of 50 new water fountains’, 18 July, https://tinyurl.com/london-fountains
28 In the EU, it is illegal to use the terms like ‘milk’, ‘cheese’ and ‘yoghurt’ for dairy alternatives: Beret, C. (2019), ‘Soy milk vs. EU law: who’s really harmed by labeling bans?’, 22 March, Medium, https://tinyurl.com/beret2019
29 Morris, H. (2019), ‘Global average per capita tissue consumption stands at above 5kg – but 10kg is possible’, 1 December. Tissue World Magazine, https://tinyurl.com/world-tissue
30 Roos, G. (2009), ‘Tesco to roll out carbon labels for TP and kitchen towels’, 22 May. Environment + Energy Leader, https://tinyurl.com/roos2009. Tesco had a short-lived campaign of carbon labelling their products from 2009 to 2012. I’m still going to go with the numbers they used for toilet paper, as they’re the only source that I can find on this.
31 For washing fish by hand, I have used a 90 per cent efficient boiler with a temperature of 50°C and 31.5 litres of water – half of what the average person uses for doing a full load of dishes according to Stokes, T. (2006), ‘Washing dishes by hand wastes water’, EcoStreet, 21 July, https://tinyurl.com/washing-dishes. At the higher end of hand washing I have used a 60 per cent efficient boiler at a scalding 65°C and using 126 litres of water (twice the average).
32 According to the appliance manufacturer Gorenje, the bacterial counts per plate is 390 for hand washing compared to 1 in a dishwasher: Gorenje (2017), ‘What is more efficient: washing the dishes by hand or using a dishwasher?’ 24 March, https://tinyurl.com/gorenje-bacteria
33 For the dishwasher, I have taken into account both the use phase and the embodied emissions of the dishwasher itself. The EEIO model gives us a figure of 270kg CO2e for a brand-new dishwasher, which works out as 0.1kg CO2e per wash assuming four washes a week over a 12.5-year lifetime. For the use-phase, I have used the consumption figures of a Bosch A+ efficiency model for the 65°C intensive wash and a 50°C economy wash and multiplied the kWh by the UK emissions factor, Bosch, ‘Serie 6 free-standing dishwasher 60 cm white’, https://tinyurl.com/dishwasher-bosch
34 A whole bottle of washing-up liquid probably has a footprint of about 1kg CO2e.
35 For the number up to the farm gate, I’ve used a 2008 report by the UK government’s Department for Environment, Food and Rural Affairs (Defra): Defra (2008), ‘Final report for Defra project FO0103: comparative life cycle assessment of food commodities procured for UK consumption through a diversity of supply chains’, https://tinyurl.com/defra-fruit
500 grams to 1 kilos
1 The figures come from models used by Small World Consulting (www.sw-consulting.co.uk). An input–output approach is used for the fuel supply chains and the depreciation of the embodied emissions in the car and its manufacture.
2 Derived from Defra (2008), ‘Passenger transport emissions factors: methodology paper’. Available from www.defra.gov.uk/environment/business/reporting/pdf/passenger-transport.pdf
3 All mugs vary. This is based on a report by Starbucks on their own mugs. Can we trust a source with such obvious interests? Well, the results more or less square with my back-of-envelope calculations, http://business.edf.org/files/2014/03/starbucks-report-april2000.pdf (since the release of the book this source is no longer available online).
4 I’ve used the numbers up to the farm gate from the following studies. For instant coffee, I’ve used Busser, S., Steiner, R., and Jungbluth, N. (2008) ‘LCA of packed food products: the function of flexible packaging’, www.seeds4green.org/sites/default/files/ESU_-_Flexible_Packaging_2008_-_Exec_Sum.pdf. For ground coffee I’ve used Humbert, S., Loerincik, Y., Rossi, V., Margni, M., and Jolliet, O. (2009) ‘Life cycle assessment of spray dried soluble coffee and comparison with alternatives (drip filter and capsule espresso)’. Journal of Cleaner Production, 17, 1351–1358, www.sciencedirect.com/science/article/pii/S0959652609001474. And for tea I’ve used Doublet, G., and Jungbluth, N. (2010), ‘Life cycle assessment of drinking Darjeeling tea: conventional and organic Darjeeling tea’, http://docplayer.net/31742051-Life-cycle-assessment-of-drinking-darjeeling-tea.html. For all post-farm-gate processing, I’ve used data from work with Booths.
5 All my calculations are based on a 250ml mug. I’ve allowed 1.5g of tea (with a footprint of 6.2kg CO2e per kg), 2g of instant coffee (with a footprint of 17.5kg CO2e per kg) and 9g of ground coffee (with a footprint of 5.8kg CO2e per kg). I’ve assumed 25ml of added milk (excluding the lattes).
6 The data I’ve used comes from Defra UK waste statistics (2019), https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/874265/UK_Statistics_on_Waste_statistical_notice_March_2020_accessible_FINAL_rev_v0.5.pdf (since the release of the book this source is no longer available online. More recent data is available here: https://www.gov.uk/government/statistics/uk-waste-data/uk-statistics-on-waste). To keep things simple, I’m not going to look at the 12 per cent of general waste that gets incinerated instead of being sent to landfill. It doesn’t change the overall picture much.
7 The breakdown of emissions from bread up to the farm gate comes from Goucher, L., Bruce, R., Cameron, D., Koh, S.C.L., and Horton, P. (2017), ‘The environmental impact of fertilizer embodied in a wheat-to-bread supply chain’. Nature Plants, 3, 1–5, www.nature.com/articles/nplants201712#Sec7
8 From Wrap (2008), ‘The food we waste’, Waste & Resources Action Programme (WRAP), Banbury. Available at http://democratic.bracknell-forest.gov.uk/(S(5ekd4s45g02uqi55rd4oz545))/documents/s10996/Thepercent20Foodpercent20Wepercent20Waste.pdf. The overall figure of 30 per cent waste includes bones and other bits that we don’t all consider edible.
9 This comes from a piece of work from 2015, ‘The Greenhouse Gas Footprint of Everards Brewery Ltd’.
10 I have based the pizza base and tomato sauce from a BBC food recipe: https://tinyurl.com/bbc-pizza. The pizza base is made with 150g of flour plus some yeast and vegetable oil, and the tomato base is 100ml of tomato passata with some herbs, garlic and salt. Each pizza also has a fresh tomato on top, which I’m assuming are the ‘loose’ salad variety which have been grown somewhere in the South of Europe and transported a few thousand miles by road.
11 For mackerel, cod, tuna and trout I have used numbers up to the farm gate from Nielsen, P.H., Nielsen, A.M., Weidman, B.P., Dalgaard, R., and Halberg, N. (2003), ‘LCA food data base: “lifecycle assessment of basic food”’ (2000 to 2003). Aarhus University, Denmark. For shrimp and lobster I have used numbers from Poore and Nemecek (2018) ‘Reducing food’s environmental impacts through producers and consumers’. Science, 992(6392), 987–992, https://tinyurl.com/poore2018. For post farm gate processing, I have used data from my work with Booths: Berners-Lee, M., Moss, J., and Hoolahan, C. (2014), ‘The greenhouse gas footprint of Booths’. Small World Consulting, https://tinyurl.com/booths-footprint
12 Not to plug my other books too much, but I do go into more detail in There Is No Planet B (2019).
13 A 2014 study estimated that restoring 424,000 hectares of rainforest in Brazil would cost $198 million per year for three years, followed by a drop in price thereafter, so I’m going to assume a total price tag of $972 million. I’ve assumed each hectare will sequester 500 tonnes CO2e (assuming it’s left alone for at least 200 years), so despite the hefty cost it would still work out at a massive 220 tonnes CO2e per £1 spent, www.sciencemag.org/news/2014/08/affordable-price-tag-saving-brazils-atlantic-rainforest
14 Based on £4000 per panel in the UK and a carbon saving of 8820kg CO2e over the lifetime of the panel.
15 This figure is drawn directly from work I recently did for an app developer, part of which looked at the emissions of the average UK grocery basket.
16 The average price per kWh is 16.3p, according to www.ukpower.co.uk/home_energy/tariffs-per-unit-kwh, so 2.1kg CO2e per £ spent for UK electricity (0.34kg CO2e/kWh).
17 My petrol figure is based on a petrol cost of 17p per mile for an average petrol car. This takes account of the extraction, shipping and refining of the fuel, but not the depreciation or maintenance of the car.
18 ‘Sustainable lifestyle’: this is a tricky expression. It doesn’t bear much scrutiny and we could get hopelessly bogged down defining it. However, I strongly suspect that whatever your definition, I would still stand by my assertion that it leaves plenty of scope for reading.
19 I’m using conversion factors of 1.59kg, 2.59kg and 2.70kg CO2e per kilo for printing on recycled, typical UK mix and 100 per cent virgin paper. Confederation of Paper Industries (2006), ‘UK paper making Industries statistical facts sheet’, www.paper.org.uk/info/reports/fact2006colour0707.pdf (since the release of the book this source is no longer available online).
A life cycle analysis by Dowd-Hinkle (2012) estimated the footprint of an Amazon Kindle at 22.3kg CO2e, of which 21.5kg CO2e are from the manufacturing and transport. I have adjusted the latter figure upward to adjust for the truncation error that most life cycle analyses make when estimating embodied footprint and which is about 40 per cent of the ‘real’ embodied footprint. Dowd-Hinkle estimates the use phase electricity at only 0.6kg CO2e over three years, Dowd-Hinkle, D.J. (2012), ‘Kindle vs. printed book: an environmental analysis’. Thesis, Rochester Institute of Technology, ttps://tinyurl.com/dowd-hinkle2012. I come to a similar figure when I use the approach I took in the last edition of this book. At the time of writing, you can get an Amazon Kindle Paperwhite (released 2018) for £119.99. If I multiply this by the emissions per pound spent in the computer manufacturing sector – 0.180kg CO2e per £1 – I get to 22kg CO2e. If we compare this to the embodied footprint of an iPad, which comes in at 130kg CO2e and 217kg if adjusted for truncation error, the Kindle has a much lower footprint. Based on an Apple LCA for the 12.9-inch iPad Pro (fourth generation) with 128GB: https://tinyurl.com/apple-ipad
20 This comes from working out the carbon footprint of a kWh of heat and a kWh of electricity in the UK. A typical bath can hold about 120 litres (with you in it, too). I’ve taken the cold-water temperature to be 10°C and a comfortable bath temperature to be 40°C. The heat capacity of water is 4.2 kilojoules per litre. I’ve assumed a 90 per cent efficient boiler and used a conversion factor of 0.221kg CO2e per kWh for heat produced by natural gas (this uses a figure from Defra for the direct emissions of burning gas and adds to that a figure from our input–output model to estimate the supply chain impacts). There are 3600 kilojoules per kWh. The footprint of the bath in kg CO2e is 120 × (39 – 8) × 4.2 × 0.225/(3600 × 90 per cent). For UK electricity, I’ve used the same formula described above but with a carbon footprint of 0.339kg CO₂ per kWh generated (again, this is the figure from Defra plus the figure from the input–output model to add on the estimate of supply chain impacts). The footprint of the water consumption is negligible.
1 kilo to 10 kilos
1 Emissions up to the farm gate are from Williams, A.G., Audsley, E., and Sandars, D.L. (2006), ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’. Defra Research Project ISO205, Cranfield University and Defra, https://tinyurl.com/williams2006 .
Emissions beyond the farm gate are based on a study by Small World Consulting for Booths supermarkets: Berners-Lee, M., Moss, J., and Hoolahan, C. (2014), ‘The greenhouse gas footprint of Booths’. Small World Consulting, https://tinyurl.com/booths-footprint.
2 The figure for soya milk and the higher figure for global average milk can be found in Poore, J., and Nemecek, T. (2018). ‘Reducing food’s environmental impacts through producers and consumers’, Science,992(6392), 987–992, https://tinyurl.com/poore2018. Thanks also to Joseph Poore for kindly providing additional data for oat, rice and almond milk.
3 Numbers up to the farm gate come from Garnett, T. (2007), ‘The alcohol we drink and its contribution to UK greenhouse gas emissions – a discussion paper’, Food Climate Research Network, https://tinyurl.com/garnett2007
The rest of my numbers come from my work with Booths supermarkets: Berners-Lee, M., Moss, J., and Hoolahan, C. (2014), ‘The greenhouse gas footprint of Booths’, Small World Consulting, https://tinyurl.com/booths-footprint
4 For this I’ve used the thesis of a master’s student I co-supervised: Swinn, R. (2017), ‘A comparative LCA of the carbon footprint of cut-flowers: British, Dutch and Kenya. Environment and Development’. Thesis, Lancaster University. The thesis is summarised here: https://tinyurl.com/footprint-flowers
5 Impacts up to the farm gate are from: Williams, A.G., Audsley, E., and Sandars, D.L. (2006), ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’. Defra Research Project ISO205. Cranfield University and Defra, https://tinyurl.com/williams2006.
Impacts from the farm to the checkout are from Small World Consulting’s work for Booths supermarkets: Berners-Lee, M., Moss, J., and Hoolahan, C. (2014), ‘The greenhouse gas footprint of Booths’, Small World Consulting, https://tinyurl.com/booths-footprint
6 I’ve taken the data from: Poore, J., and Nemecek, T. (2018), ‘Reducing food’s environmental impacts through producers and consumers’. Science, 992(6392), 987–992, https://tinyurl.com/poore2018. In almost all cases, the results are strikingly similar to my own research, including my work for supermarkets – unsurprisingly, because our sources are mainly the same.
7 See, for example, Lappeenranta University of Technology (2017), ‘Protein produced from electricity to alleviate world hunger’, https://tinyurl.com/protein-electricity. Thanks also to Channel 4 and George Monbiot for an interesting piece on this in their 2020 documentary Apocalypse Cow: How Meat Killed the Planet, https://tinyurl.com/apocalypse-cow
8 I’ve based all my numbers on the consumption figures of a Bosch A+++ Series 4 washing machines (and Series 6 tumble dryers), https://tinyurl.com/washing-machine-bosch. The Small World Consulting SWC EEIO model has an estimated carbon footprint of 281kg CO2e for the washing machine, and I have assumed that you’ll get through two loads a week for a 10-year lifetime.
9 The rating system seems a bit unfair on condensing dryers since it doesn’t take account of the fact that they keep the heat in the home instead of belching it into the outside world.
10 Reverse osmosis (RO) desalination of seawater produces anywhere between 0.4 and 6.7kg CO2e per cubic metre, compared to 0.3–34.3kg CO2e per cubic metre for thermal desalination techniques, according to a literature review by Cornejo, P. K., Santana, M.V., Hokanson, D.R., Mihelcic, J.R., and Zhang, Q. (2014), ‘Carbon footprint of water reuse and desalination: a review of greenhouse gas emissions and estimation tools’. Journal of Water Reuse and Desalination, 4(4), 238–252, https://tinyurl.com/cornejo2014. Reverse osmosis O desalination of brackish water is lower carbon (0.4–2.5kg CO2e per cubic metre) and water reuse lower still (0.1–2.4kg CO2e per cubic metre).
11 Global desalination was at 95 million cubic metres per day in 2019 (up from the 2009 estimate of 60 million nithe first edition of this book) according to Jones, E., Qadir, M., van Vliet, M.T., Smakhtin, V., and Kang, S.M. (2019), ‘The state of desalination and brine production: a global outlook’. Science of the Total Environment, 657, 1343–1356, https://tinyurl.com/jones-2019. 48 per cent of this desalination takes place in the Middle East and North Africa regions, and 55 per cent of brine production takes place in these regions (brine production is at 141.5 million per cubic metre per day).
Another study comes out with similar numbers and the low-end estimate of global annual emissions from desalination: Duong, H.C., Ansari, A.J., Nghiem, L.D., Pham, T.M., and Pham, T.D. (2018), ‘Low carbon desalination by innovative membrane materials and processes’. Current Pollution Reports, 4(4), 251–264, https://tinyurl.com/duong-2018
12 Readers who recall the first edition of Bananas may notice that this is a lot less than the 1.6 per cent of global annual emissions I estimated desalination as responsible for 10 years ago. I overestimated my calculations a bit in the old book and 0.15–0.4 per cent of global emissions is much more realistic.
13 Information on Seawater Greenhouse Ltd comes from Wikipedia, https://tinyurl.com/wiki-seawater.
14 Chen, W., Chen, S., Liang, T., Zhang, Q., Fan, Z., Yin, H., et al. (2018), ‘High-flux water desalination with interfacial salt sieving effect in nanoporous carbon composite membranes’. Nature Nanotechnology, 13(4), 345–350, https://tinyurl.com/chen-2018. See also: www.nature.com/articles/s41565-018-0067-5 and www.nature.com/articles/s41565-018-0118-y.pdf
15 US Department of Agriculture (USDA) Food Safety and Inspection Service (2013), ‘Molds on food: are they dangerous?’, https://tinyurl.com/usda2013.
16 Williams, A.G., Audsley, E., and Sandars, D.L. (2006), ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’. Defra Research Project ISO205. Cranfield University and Defra, https://tinyurl.com/williams2006
17 Williams, A.G., Audsley, E., and Sandars, D.L. (2006), ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’. Defra Research Project ISO205. Cranfield University and Defra, https://tinyurl.com/williams2006
18 International Rice Research Institute, www.irri.org/
19 There were 518 billion tonnes of rice produced in 2016: Grain Central (2018), ‘Global rice consumption continues to grow’, 26 March, https://tinyurl.com/grain-central. I imagine that the global retail emissions will be much smaller than they are in the UK, so I’ve gone for the lower estimate to calculate total emissions of around 3.5 per cent.
20 All statistics come from the International Rice Research Institute’s Rice Stats database, https://www.irri.org/rice-information-gateway.
21 All the data for plastic, with the exception of nylon, has come from the following study: Zheng, J., and Suh, S. (2019), ‘Strategies to reduce the global carbon footprint of plastics’. Nature Climate Change, 9(5), 374–378, https://tinyurl.com/zheng2019.
22 The number for nylon comes from Hammond, G.P., and Jones, C.I. (2019), Inventory of Carbon and Energy (ICE) database V3.0. ‘Embodied carbon – the ICE database’, circularecology.com. Available for download from https://tinyurl.com/ice-database.
23 This report highlights some of the health problems: Azoulay, D., Villa, P., Arellano, Y., Gordon, M.F., Moon, D., Miller, K.A., and Thompson, K. (2019), ‘Plastic and health: the hidden costs of a plastic planet’, Centre for International Developmental Law, https://tinyurl.com/azoulay2019
24 Geye, R., Jambeck, J., and Law, K.L. (2017), ‘Production, use, and fate of all plastics ever made’. Science, 3(7), 1–5, https://tinyurl.com/geyer2017
25 Defra (2008), ‘Final report for Defra project FO0103: comparative life cycle assessment of food commodities procured for UK consumption through a diversity of supply chains’, https://tinyurl.com/defra-fruit.
The two lower numbers here come from Williams, A.G., Audsley, E., and Sandars, D.L. (2006), ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’. Defra Research Project ISO205. Cranfield University and Defra, https://tinyurl.com/williams2006
26 Williams, A.G., Audsley, E., and Sandars, D.L. (2006), ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’. Defra Research Project ISO205. Cranfield University and Defra, https://tinyurl.com/williams2006.
Although this looks like the best information around, it is contested. I know farmers who are highly critical of the assumptions made in the same report about organic dairy herds. My high-end figure is adjusted upwards from Cranfield’s 38.6kg CO2e per kilo to take account of produce from a colder time of year, rather than the year-round average reported in the Cranfield study. Since the first edition of the book, I have updated the figure with up-to-date electricity numbers up to the farm gate to give a number of 28.2kg CO2e.
27 Williams, A.G., Audsley, E., and Sandars, D.L. (2006), ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’. Defra Research Project ISO205. Cranfield University and Defra, https://tinyurl.com/williams2006.
Defra (2008), ‘Final report for Defra project FO0103: comparative life cycle assessment of food commodities procured for UK consumption through a diversity of supply chains’, https://tinyurl.com/defra-fruit
10 kilos to 100 kilos
1 The widow of former Philippines president Ferdinand Marcos was listed by Newsweek as one of the 100 ‘greediest people of all time’. She gained some of her notoriety from her shoe collection, gathered while plenty of her fellow citizens lived in poverty.
2 A weakness of the input–output model I used for this is that it assumes that Chinese production is as carbon efficient as UK manufacture. It isn’t. It’s worse. In reality, a key carbon decision for footwear suppliers is where to have product made.
3 Periyasamy, A.P., and Durasisamy, G. (2019), ‘Carbon footprint on denim manufacturing’. Handbook of Eco-materials, 1581–1598, https://tinyurl.com/periyasamy2019.
4 Environmental Improvement Potential of Textiles (IMPRO‐Textiles), JRC Scientific and technical reports: Beton, A., Dias, D., Farrant, L., Gibon, T., Le Guern, Y., Desaxce, M., et al.(2014), ‘Environmental improvement potential of textiles (IMPRO-textiles)’, European Commission, https://publications.jrc.ec.europa.eu/repository/handle/JRC85895 (this link has been updated for the online version of the notes and references).
5 Niinimäaki, K., Peters, G., Dahlbo, H., Perry, P., Rissanen, T., and Gwilt, A. (2020), ‘The environmental price of fast fashion’. Nature Reviews Earth and Environment, 1, 189–200, https://tinyurl.com/niinimaki2020.
6 Clothing footprint of the UK, comparison to global estimates, based on House of Commons Environmental Audit Committee (2019), ‘Fixing fashion: clothing consumption and sustainability’, https://tinyurl.com/fixing-fashion.
7 This is the additional footprint arising from your decision to make the commute, given that everyone else is already on the road. It is also the difference you can make by stopping commuting. It is more than your fair share of the total pollution, which would only be double rather than three times the normal emissions from driving that distance on an empty road.
8 To make it very simple, think of a queue 10 cars long, moving at one car per minute. Assuming the queue has stayed the same size, those 10 cars will between them have queued for 100 car minutes by the time they have all gone through. Add your car and you have 11 cars all queuing for 11 minutes. That’s 21 minutes more queuing, even though you experience just 11 minutes. You get the same effect when you model slightly more complicated things such as ring roads with queues at each roundabout. None of this takes account of the possibility that you are the person who gets stuck at the junction, triggering gridlock and a whole new multiplier effect.
9 The Highway Code figures for typical stopping distances are 96m (24 car lengths) at 70 mph and just 53m (13 car lengths) at 50 mph, https://tinyurl.com/highway-code. The stopping distance has two components: the thinking distance, which is proportional to your speed, and the larger braking distance, which is proportional to the square of your speed. On this basis, a lane at 50 mph can take nearly twice the traffic of one at 70 mph. So there is no need for anyone to queue when the lane closes, provided that no one leaves it to the last moment to change lanes. In reality, most drivers don’t leave as much as their stopping distance between them and the car in front, but the principles here still apply if they keep leaving the same proportion of that stopping distance between themselves and the next car as they slow down.
10 This information comes from a Chatham House report: Lehne, J., and Preston, F. (2018), ‘Making concrete change: innovation in low-carbon cement and concrete’, https://tinyurl.com/lehne2018.
11 Vizcaíno-Andrésa, L.M., Sánchez-Berriela, S., Damas-Carrerab, S., Pérez-Hernándezc, A., Scrivenerd, K.L, and Martirena-Hernández, J.F. (2015), ‘Industrial trial to produce a low clinker, low carbon cement’. Materiales de Construccion, 65, 317, https://tinyurl.com/vizcaino2015.
12 Maddalena, R., Roberts, J., and Hamilton, A. (2018), ‘Can Portland cement be replaced by low-carbon alternative materials? A study on the thermal properties and carbon emissions of innovative cements’. Journal of Cleaner Production, 186, 933–942, https://tinyurl.com/maddalena2018.
13 A staggering 5 hours of life are lost through death per 1000 miles of driving. My sum was just this: loss of life expectancy per mile = 2538 deaths on UK roads per year × 48 remaining years of life expectancy of an average driver, divided by 216 billion person car miles on UK roads per year = 5 hours life lost per 1000 miles of driving (National Travel Survey, Department of Transport, 2009). I’ve based my sums on your having a life expectancy of another 48 years (I picked a 40-year-old man with a healthy lifestyle and because it gives me a nice round number), but you might want to adjust for your own situation. I haven’t taken account of the fact that some of the deaths are of pedestrians (thinking that you might be just as bothered about killing others as you are yourself), but I also haven’t taken into account the possibility that you might acquire one of the 26,000 serious injuries or 150,000 minor injuries that are served up to UK car users each year. It’s a lot better to be injured than killed on the road, but injury happens 10 times more often. I have also assumed that motorway journeys are averagely safe per mile compared with other car trips.
14 Travel time estimate based on the AA Route Planner, https://tinyurl.com/aa-route
15 An iPhone 11 with 128 GB has an embodied carbon footprint of 63kg CO2e (this includes production and transport) according to Apple, https://tinyurl.com/iphone11-footprint. I have adjusted the embodied figure upward for truncation error to 105kg CO2e. Apple are quite optimistic with the assumption of three years of life, but according to Belkhir and Elmeligi, the average life of a smartphone is two years, so we have assumed that for all the headline figures: Belkhir, L., and Elmeligi, A. (2018), ‘Assessing ICT global emissions footprint: trends to 2040 and recommendations’. Journal of Cleaner Production, 177, 448–463, https://tinyurl.com/belkhir2018.
Apple reports that the iPhone 11 has a battery capacity of 11.91 Wh, https://www.apple.com/by/iphone-11/specs/ (this link has been updated for the online version of the notes and references) and ZDNet estimates that this lasts for 1.6 days, https://tinyurl.com/zdnet-iphone, so one day uses 7.44 Wh. Using a UK electricity intensity of 0.34kg CO2e per kWh, and considering charger efficiency is around 85 per cent, https://tinyurl.com/charger-efficiency, that’s close to 3g per day in electricity consumption.
The company RescueTime (https://blog.rescuetime.com/screen-time-stats-2018/) analysed data from 11,000 users of their app and concluded that people spend an average of 3 hours and 15 minutes on their phones. MacKay, J. (2019), ‘Screen time stats 2019: Here’s how much you use your phone during the workday’, 21 March, https://tinyurl.com/rescue-time.
Allocating the electricity per day to the 3 hours 15 minutes that you use your phone actively, the footprint from electricity per minute is 0.02g CO2e, or 1.1kg CO2e per year. When you use your phone just 1 hour per day, it’s 0.3kg CO2e per year and, for using it 10 hours a day, it’s 1.7kg CO2e per year. Clearly, it doesn’t make much of a difference because of the size of the embodied footprint.
For the use of networks and data centres, I have used estimates of electricity use in networks and data centres from Ericsson: 5 watts for the networks, 5 watts in data centres and 10 watts for your WiFi router, but this is split across two people, so 5 watts per user. The footprint of doing something online depends on how long you spend on your device and on the internet : Ericsson (2020), ‘A quick guide to your digital carbon footprint – deconstructing information and communication technology’s carbon emissions’, https://tinyurl.com/ericsson2020, and specifically their background report (www.ericsson.com/4906b7/assets/local/reports-papers/consumerlab/reports/2020/background-calculations-to-true-and-false-report.pdf).
I’m using a global electricity mix carbon intensity for the networks and data centres, because you might well use some that are in other countries when you use the internet, but for the router I have assumed UK electricity. I have assumed that you have a WiFi router running 24 hours a day and allocated the electricity to the average 2.5 hours that people use the internet at home per day, according to: Center for the Digital Future Report (2018), ‘The 2018 digital future report: surveying the digital future’, https://tinyurl.com/digitalfuture2018.
That comes to 0.4g CO2e per minute (22.5kg per year) WiFi use if you use the internet for 3 hours 15 minutes. Over the course of a year, that adds up to 15kg, or 17kg (or 42kg), if you use your phone for 1 (or 10) hours, respectively, assuming you also use one other device to access the Wifi, so only half of the WiFi router’s electricity use per person ‘belongs’ to the smartphone. The footprint is not directly proportional to how long you use it actively, because of the way that the WiFi router is allocated. I have assumed that you use it for 1 hour or 8 hours per day, respectively. In the case of using your phone for 1 or 10 hours every day, I have allocated the WiFi router’s daily electricity use to 1 and 8 hours per day, respectively. That comes to 17kg per year for 1 hour use per day, or 42kg per year for 10 hours per day, for the internet use. If you use mobile networks, which don’t require a WiFi router, it’s just 0.1g per minute.
Ericsson arrives at a slightly higher figure, for a year’s use of the internet through your smartphone has a footprint of 25kg CO2e, based on a global electricity factor of 0.6kg CO2e per kWh. When I adjust this for my electricity figure of 0.63kg CO2e per kWh, I get to 26.3kg. Ericsson bases this on 4 hours of use per day. For 3 hours 15 minutes, this breaks down to 21.3kg CO2e per year, and 8.1kg and 80.8kg if you use the internet for 1 or 10 hours per day, respectively.
16 Based on an iPhone 11, including 0.7g for the embodied footprint, 0.2g for use phase footprint and 0.4g for electricity use in the network, data centres and the WiFi router.
17 Belkhir, L., and Elmeligi, A. (2018), ‘Assessing ICT global emissions footprint: trends to 2040 and recommendations’. Journal of Cleaner Production, 177, 448–463, https://www.sciencedirect.com/science/article/abs/pii/S095965261733233X (this link has been updated for the online version of the notes and references). This study concluded that the average lifetime of a smartphone is two years. This is not because the phone wouldn’t last any longer but because phone contracts and fashion encourage people to change their phones more often than necessary. However, there is some evidence that the useful life of smartphones might be increasing, thereby spreading the embodied carbon footprint of the device over a longer time period. The NPD (2019) reported that, in the US, the average use has increased to 32 months in 2017, up from 25 months in 2016: NPD (2018), ‘The average upgrade cycle of a smartphone in the US is 32 months, according to NPD connected intelligence’, 12 July, https://tinyurl.com/npd-2018
18 Cisco (2020) estimates that there were 7.3 billion mobile phones in 2018 and that there will be 8.2 billion in 2025. Based on this, I extrapolated 7.7 billion in 2020. I have multiplied this by 76kg CO2e per phone, based on the iPhone 11 used for 3 hours and 15 minutes per day and kept for two years, assuming global electricity rather than UK electricity. This includes the emissions embodied in the device, the electricity to run the device and the networks and data centres, and is 1 per cent of 2018 global greenhouse gas emissions (see The Cloud and the world’s data centres, p.166). Of course, not all the world’s mobile phones are iPhones and the average of 3 hours 15 minutes use per day for smartphones might be different for other mobile phones, so this is just a rough estimate and probably an overestimate: Cisco (2020), ‘Cisco Annual Internet Report (2018–2023) White Paper’, https://tinyurl.com/cisco-report-2020
19 Jens Malmodin, senior specialist at Ericsson and an expert in the energy and carbon footprint of networks, told me that he estimates that mobile networks used for transmitting texts and voice calls use on average 2 watts. For a UK call using 0.34kg CO2e per kWh, a 1-minute phone call would have a carbon footprint of 0.1g CO2e.
20 A European Environmental Bureau (EEB) report estimates that extending the lifetime of all smartphones by one year (three years, five years) would save 2.1 million tonnes CO2e (4.3 million tonnes CO2e, 5.5 million tonnes CO2e) per year in the EU by 2030: EEB (2019), ‘Coolproducts don’t cost the Earth’, https://tinyurl.com/eeb-2019
21 You can locate your local recycling centre for electrical waste and find out more about what happens with it there on Recycle Now’s website: https://www.recyclenow.com/recycle-an-item (this link has been updated for the online version of the notes and references).
100 kilos to 1000 kilos
1 I have calculated the average carbon intensity of the economy for all countries classified as low income by the World Bank, using their estimates of consumption-based CO2e emissions in 2016, where this data was available – Ritchie, H., and Roser, M. (2019), ‘CO2 and greenhouse gas emissions’. Our World in Data, https://ourworldindata.org/co2-and-greenhouse-gas-emissions#co2-embedded-in-trade (this link has been updated for the online version of the notes and references) – and dividing it by total GDP in 2016 provided by the World Bank (https://tinyurl.com/world-bank-gdp). The average carbon intensity is 0.64kg CO2e per US dollar GDP for low-income countries and 0.21kg for the UK. So, on average, low-income countries have a carbon intensity that is 3.1 times higher than that of the UK. This is a very crude measure, of course.
2 Phillips, D. (2018), ‘Illegal mining in Amazon rainforest has become an “epidemic”’, Guardian, 10 December,https://tinyurl.com/phillips-2018.
According to research by the Amazon Socio-environmental, Geo-referenced Information Project (RAISG), using satellite images of the Amazon, there has been an exponential increase in illegal gold mining in recent years, including in indigenous and protected natural areas. This has been partly sparked by spikes in gold prices after the 2009 recession. The mining does not just lead to deforestation, but also mercury contamination, which is used for purifying the gold and has ill effects on ecosystems and human health.
3 Some of these have been listed in this article by the Independent: Bergman, S. (2019), ‘9 best ethical and sustainable jewellery brands’. Independent, 5 February, https://tinyurl.com/bergman2019.
The Fairtrade Foundation also lists some: Hackett, F. (2020), ‘7 ethical and sustainable jewellery brands’, 12 February, https://tinyurl.com/hackett2020
4 The figure of 20 per cent of presents being unwanted comes from: Haq, G., Owen. A., Dawkins, E., and Barrett, J. (2007), ‘The carbon cost of Christmas’. Stockholm Environment Institute, https://tinyurl.com/haq2007
5 Taken from the ICE database: Hammond, G.P., and Jones, C.I. (2019), Inventory of Carbon and Energy (ICE) database V3.0, circularecology.com. Available for download here from https://tinyurl.com/ice-database
6 See note 5 above.
7 All information comes from the Energy Saving Trust (EST)’s web site: https://tinyurl.com/est-loft
8 You can apply for a government grant under the energy company obligation scheme: https://tinyurl.com/insulation-grant).
9 The ICE database gives a figure of 1.28kg CO2e per kilo for wool. I’ve gone with this, despite the problems that process life cycle analysis has with underestimating absolute numbers. Hammond, G.P., and Jones, C.I. (2019), Inventory of Carbon and Energy (ICE) database V3.0, circularecology.com. Available for download here from https://tinyurl.com/ice-database
10 For embodied carbon, I used the following environmental reports: Apple MacBook Pro 13-inch, 1.4GHz Quad-Core processor, 128GB storage, introduced July 2019, https://www.apple.com/environment/pdf/products/notebooks/13-inch_MacBookPro_PER_June2019.pdf (this link has been updated for the online version of the notes and references). Apple MacBook Pro 16-inch, 2.3 GHz 8-core processor, 1TB storage, introduced November 2019, https://tinyurl.com/apple-16-macbook-pro; Dell Precision 5530, released June 2018, https://tinyurl.com/dell-5530; HP Chromebook 14 G5, introduced February 2018, https://h20195.www2.hp.com/v2/GetDocument.aspx?docname=c07524985 (this link has been updated for the online version of the notes and references). HP does not give a percentage for the share of embodied carbon in the total footprint, so I have assumed the same percentage as for the Dell Precision 5530: 84 per cent.
11 For electricity consumption, I used a UK electricity intensity of 0.34kg CO2e per kWh and information on power use. For the Apple MacBooks, I divided the battery capacity by the length of time it lasts to arrive at a per-hour electricity consumption. This is based on data from Apple: https://tinyurl.com/macbook-13-specs.
Estimates for the HP laptop are based on its typical annual energy consumption of 19.7 kWh, assuming it is used three hours per day.
The other estimates for average laptops, desktop PCs and gaming PCs are based on: Ericsson (2020), ‘A quick guide to your digital carbon footprint – deconstructing information and communication technology’s carbon emissions’, https://tinyurl.com/ericsson2020. Ericsson reports that an average laptop uses 30 watts, a PC with an external screen uses 150 watts and a gaming PC with external screen uses 200 watts.
12 For the use of networks and data centres, I have used estimates of electricity use in networks and data centres from Ericsson: 5 watts for the networks, 5 watts in data centres and 10 watts for your WiFi router, but I’m assuming you share the WiFi with one other person, so 5 watts per user. Ericsson (2020), ‘A quick guide to your digital carbon footprint – deconstructing information and communication technology’s carbon emissions’, https://tinyurl.com/ericsson2020 and specifically their background report: https://tinyurl.com/ericsson2020-background.
I’m using a global electricity mix carbon intensity for the networks and data centres, because you might well use some that are in other countries when you use the internet, but for the router I have assumed UK electricity. I have assumed that you have a WiFi router running 24 hours a day, and allocated the electricity to the average 2.5 hours that people use the internet at home per day, according to: Center for the Digital Future (2018), ‘The 2018 digital future project: surveying the digital future’, https://tinyurl.com/digitalfuture2018.
That comes to 22kg CO2e per hour WiFi use if you use the internet for 3 hours 15 minutes. Over the course of a year, that adds up to 15kg, assuming you also use one other device to access the Wifi, so only half of the WiFi router’s electricity use per person is associated with the computer.
13 At Small World Consulting, we looked into some fairly standard methodologies used for life cycle analyses of different types of products, including that used by Apple, and used this to map the likely truncations against a system-complete input–output methodology, to arrive at a figure for the proportion of all carbon that would be likely to be missed from the footprint. For different types of products the proportion that we can expect to be truncated varies. For IT equipment we came to a best estimate of 40 per cent truncation error for the embodied carbon and 18 per cent for the use phase. If we get time, we’ll publish what we did!
14 De Decker, K. (2009), ‘The monster footprint of digital technology’, Low-Tech Magazine, 16 June, https://tinyurl.com/dedecker2009. I’m guessing that the carbon footprint per gram is the same as it was 10 years ago, when I wrote the first edition of this book but of course a 2g chip is a lot more powerful these days than it was back then. The paper this article refers to is: www.researchgate.net/publication/5593533_The_17_Kilogram_Microchip_Energy_and_Material_Use_in_the_Production_of_Semiconductor_Devices
15 For the goldfish, I’ve assumed a 45-litre tank containing two goldfish. I’ve estimated that the tank will use up about 150 kWh per year, which works out at roughly 25kg CO₂e per year: Algone, ‘Aquarium power consumption. Energy cost of a fish tank’, https://tinyurl.com/fishtank-energy. I’ve assumed the food is negligible.
16 The study I’ve based the numbers on comes from Martens, P., Su, B., and Deblomme, S. (2019), ‘The ecological paw print of companion dogs and cats’. BioScience, 69(6), 467–474, https://tinyurl.com/martens2019.
17 See, for example, Henriques, J. (2020), ‘Can dogs be vegetarian?’ Dogs Naturally, 6 March, https://tinyurl.com/henriques2020.
18 Su, B., Martens, P., and Enders-Slegers, M.J. (2018), ‘A neglected predictor of environmental damage: the ecological paw print and carbon emissions of food consumption by companion dogs and cats in China’. Journal of Cleaner Production, 194, 1–11, https://tinyurl.com/martens-2018
19 According to Moneysavingexpert.com, the average cost of surgery at the vet is £1500: Schraer, N. (2018), ‘Millions of pet owners risk paying thousands of pounds in vet bills’, 29 May, https://tinyurl.com/schraer2018. The EEIO model has veterinary services at 0.144kg CO₂e per £1 spent, giving the figure of 215kg CO₂e.
20 Okin, G.S. (2017), ‘Environmental impacts of food consumption by dogs and cats’. PLoS ONE, 12(8), 1–14.
21 Schwartz, L. (2014), ‘The surprisingly large carbon paw print of your beloved pet’. Salon, 20 November. https://tinyurl.com/schwartz2014
22 Small World Consulting, did a piece of work for the Ecology Building Society. We calculated that their total emissions were 284 tonnes CO2e in 2018, while their total income that year was £5,756,000. Both are reported in their 2019 annual report (https://tinyurl.com/ecologybsoc). That means a carbon intensity of 49 grams per £1.
23 Oil Change International and several other campaign groups score major banks on their policies and practices around financing of fossil fuels: Oil Change International (2020), ‘Banking on climate change 2020: fossil fuel finance report card’, https://tinyurl.com/oilchangeint2020. JPMorgan, Wells Fargo, Citi and Bank of America finance fossil fuel the most. Several British banks, including Barclays, HSBC, Santander and RBS/NatWest, have significant investments in fossil fuel, too. The campaign group Fossil Banks No Thanks also rates banks on their fossil-fuel investments (www.fossilbanks.org).
24 Ethical Consumer ranks UK banks on how socially and environmentally sound they are: Wexler, J. (2018), ‘Current accounts’. Ethical Consumer, 15 March,https://tinyurl.com/wexler2018. You have to subscribe to see the full ranking, but the top three banks in their 2018 ranking were Co-operative Bank, Triodos and Charity Bank. See also Green Eco-Friend (2020), ‘Ethical banks, and building societies, UK’, https://tinyurl.com/ecofriend2020
1 tonne to 10 tonnes
1 Based on my input–output model.
2 Based on the average coronary bypass surgery cost. The NHS reports costs per intervention for 2018–19 on their web site (https://www.england.nhs.uk/publication/2018-19-national-cost-collection-data-publication/, this link has been updated for the online version of the notes and references). Prices vary between £9888 (for an uncomplicated standard coronary artery bypass graft) and £17,977 (for a complex coronary artery bypass graft with single heart valve replacement or repair), with an average of £13,107.
3 In 2018–19, 15,000 heart bypass operations, 23,000 major hip surgeries and over 45,000 major knee surgeries were performed, according to the NHS. The average price of a hip surgery is £6279, while knee surgeries each cost £6108, on average. Assuming they are as carbon intensive as the healthcare sector is on average, that would mean a carbon footprint of 1108kg and 1078kg CO2e, respectively. Costs are drawn from the 2018–19 National schedule of NHS Costs (https://www.england.nhs.uk/publication/2018-19-national-cost-collection-data-publication/, this link has been updated for the online version of the notes and references).
4 This includes medical and dental services in hospitals and practices, as well as the manufacture of pharmaceuticals, diagnostic tests and wound dressings, and is based on my input–output model.
5 Material Economics (2019), ‘Industrial transformation 2050 – pathways to net-zero emissions from EU heavy industry’, https://tinyurl.com/materialecon2019
6 Carbon Trust (2011), ‘International carbon flows: steel, 2011’, https://tinyurl.com/carbontrust2011. Read by eye from a diagram. At the time, about half of the steel for construction was in China (https://bit.ly/2Geu0nj)
7 Thanks to Chris Goodall for this analysis: Goodall, C. (2020), ‘The extra costs of decarbonised steel’. Carbon Commentary, 14 January, https://tinyurl.com/goodall2020.
8 Ammonium nitrate (NH4NO3) fertiliser is 35 per cent nitrogen by weight. The nitrous oxide (N2O) that is released is 64 per cent nitrogen by weight. The 1 per cent of the nitrogen that is emitted is 0.55 per cent of the original weight of the fertiliser in N2O, with a global warming potential 300 times that weight in CO2 equivalent. So 1–5 per cent nitrogen released to the atmosphere is 1.65–8.25 tonnes CO2e per tonne of fertiliser applied to the crop. All the agricultural data in this section came from a lecture by Professor David Powlson during a visit to Lancaster University in November 2009. He is working with the Chinese government to get the message across to farmers.
9 China used 24 million tonnes of nitrogen fertiliser in 2017 (out of the world’s 107 million tonnes annual total) according to the International Fertilizer Organisation, https://tinyurl.com/int-fertiliser
10 Cui, Z., Zhang, H., Chen, X., Zhang, C., Ma, W., Huang, C., et al. (2018), ‘Pursuing sustainable productivity with millions of smallholder farmers’. Nature, 555(7696), 363–366, https://tinyurl.com/cui2018
11 Based on UN data, Worldometers reports that China’s population makes up 18.4 per cent of the world population, as of May 2020, https://tinyurl.com/china-population.
According to the World Bank, China had 118,900,000 hectares of arable land, while the global number was 1,423,083,180 hectares, https://tinyurl.com/china-land. This compares with 24.9 per cent arable land in the UK in 2016, for example.
12 Cui et al. report that a large-scale agricultural study giving advice to 20.9 million Chinese smallholder farmers between 2005 and 2015 led to 11 per cent increased yields and 16 per cent reduced fertiliser use, saving 1.2 million tonnes of nitrogen. The intervention reduced greenhouse gas emissions from fertiliser use by three-quarters: Cui, Z., Zhang, H., Chen, X., Zhang, C., Ma, W., Huang, C., et al. (2018), ‘Pursuing sustainable productivity with millions of smallholder farmers’. Nature, 555(7696), 363–366, https://tinyurl.com/cui2018
13 Here is a glimpse of the main issues. The amount of N2O that a jet engine produces varies with altitude, and its effect on ozone levels also depends on altitude. Furthermore, the effect of that ozone on climate is altitude dependent. Planes also cause contrails under certain atmospheric conditions, and these are known to make a short-lived but large contribution to the greenhouse effect. The contrails themselves depend on temperature, weather conditions, time of day and altitude.
14 Craig Jones, C. (2020), ‘Circular ecology, embodied carbon of solar PV: here’s why it must be included in net zero carbon buildings’. Circular Ecology, 2020, https://tinyurl.com/pv-footprint.
15 It assumes the world follows a 2°C pathway to 2050: Pehl, M., Arvesen, A., Humpenöder, F., Popp, A., Hertwich, E. G., and Luderer, G. (2017), ‘Understanding future emissions from low-carbon power systems by integration of life-cycle assessment and integrated energy modelling’. Nature Energy, 2(12), 939–945. https://tinyurl.com/pehl2017, doi:10.1038/s41560-017-0032-9
16 See this paper which makes the case that the resources required to make renewables infrastructure are not a constraint: M. Diesendorf, T. Wiedmann. ‘Implications of Trends in Energy Return on Energy Invested (EROI) for Transitioning to Renewable Electricity’. Ecological Economics, 2020; 176: 106726 DOI: 10.1016/j.ecolecon.2020.106726
17 I’m using an emissions factor for natural gas of 240g CO2e per kWh. This is a little higher than BEIS figures, as I’ve used input–output analysis to include something for the supply chain pathways that BEIS doesn’t include.
10 tonnes to 1000 tonnes
1 Prices are based on manufacturers’ prices for the most basic and most high-end configurations. Citroën C1: https://tinyurl.com/citroen-prices (since the release of the book this source is no longer available online, as the Citroën C1 has now been discontinued from the main range); Ford Focus Titanium: https://www.ford.co.uk/cars/focus/models-specs/titanium (this link has been updated for the online version of the notes and references); Toyota Prius Plug-in hybrid: https://tinyurl.com/toyota-prices (since the release of the book this source is no longer available online, as the Toyota Prius Plug-in hybrid has now been discontinued from the main range); Range Rover Sports HSE: https://tinyurl.com/rangerover-prices.
2 For example, the Carbon Brief estimates that going electric typically cuts lifetime emissions per mile to one-third of an average petrol car, based on much lower estimates of the footprint of manufacture. The reason I trust my embodied carbon estimate more is that I suspect the process life cycle analyses drawn upon here suffer from serious systematic underestimation, or ‘truncation error’ (see Where the Numbers Come From, p.216): Hausfather, Z. (2019), ‘Factcheck: how electric vehicles help to tackle climate change’. Carbon Brief, 13 May, https://tinyurl.com/hausfather2019
3 The emissions per fuel are based on rough numbers. In my calculations, I have assumed that kerosene releases 3750kg of greenhouse gases per tonne, based on my input–output model factor for kerosene. Note that rockets use RP-1, a highly refined form of kerosene, so the exact emissions per tonne will be slightly different.
The emissions per kilogram of liquid hydrogen, liquid oxygen and hydrogen peroxide are based on the energy that is required to synthesise them and the carbon intensity of global average electricity, but exclude the emissions from transport and storage of the fuel and also exclude a share of the emissions embodied in the equipment needed to synthesise and transport the fuel. Electricity figures for hydrogen are based on 50 kWh per kg at 80 per cent efficiency (according to Wikipedia, https://tinyurl.com/hydrogen-footprint), 0.23 kWh per kilogram for liquid oxygen (according to a report by the Gas Technology Institute, https://tinyurl.com/liquid-oxygen-footprint) and 10 kWh per kilogram for hydrogen peroxide (based on a study by the Frauenhofer Institute, https://tinyurl.com/hydrogen-peroxide-footprint).
Based on my input–output model factor for kerosene. Note that rockets use RP-1, a highly refined form of kerosene, so the exact emissions per tonne will be slightly different. As always, the carbon footprint numbers here are just an approximation.
4 According to Astronautix: kerosene consumption of 5897kg is based on https://tinyurl.com/new-shephard
5 119,100kg of kerosene according to. Based on the SpaceX Falcon 9 v1.1 (according to Spaceflight101, https://tinyurl.com/falcon-9).
6 According to CoolCosmos: https://tinyurl.com/space-shuttle. I have assumed that the solid fuel has the same carbon intensity as kerosene.
7 All converted from litres. Figures are from the website Space (https://tinyurl.com/moon-rocket). Shuttle data comes from Wikipedia. Other figures in my calculations were: 31 MJ (1 megajoule equals 1 million joules) per kilo for the solid fuel; I used 0.07kg CO2e per MJ as a general figure for emissions from the burning of fossil fuels and added 10 per cent for their supply chains up to the point of combustion. 143 MJ per kilo for the hydrogen.
Global average electricity intensity of 0.63kg CO2e per kWh, divided by 3.6 to get MJ >> 0.175kg CO2e per MJ; 143 MJ per kilo of hydrogen; nothing added for supply chain; 25kg CO2e per kilo of hydrogen.
8 Richard Feynman’s book What Do You Care What Other People Think? (1989) is a fascinating and entertaining account of the technical and management failures behind the disaster. It is also recommended for anyone who is trying to get some clear thinking into a bureaucracy.
9 Smoucha, E., Fitzpatrick, K., Buckingham, S., and Knox, O. (2016), ‘Life cycle analysis of the embodied carbon emissions from 14 wind turbines with rated powers between 50 kW and 3.4 Mw’. Journal of Fundamentals of Renewable Energy and Applications, 6(4), 1–10, https://tinyurl.com/smoucha2016
10 Hausfather, Z. (2018), ‘Analysis: How much “carbon budget” is left to limit global warming to 1.5C?’Carbon Brief, 9 April, https://tinyurl.com/hausfather2018. More details of carbon budgets in There Is No Planet B (2019).
Millions of tonnes
1 Aiuppa et al. estimate that Mount Etna released around 2,000 tonnes CO2 per day (that’s 730,000 tonnes per year) during quiescent passive periods when the volcano is dormant: Aiuppa, A., Federico, C., Giudice, G., Gurrieri, S., Liuzzo, M., Shinohara, H., et al. (2006), ‘Rates of carbon dioxide plume degassing from Mount Etna volcano’. Journal of Geophysical Research: Solid Earth, 111(B9), https://tinyurl.com/aiuppa2006 .
The Holuhraun eruption in Iceland in 2014 was the largest volcanic eruption since 1783 and is estimated to have emitted 5.1 million tonnes CO2: Pfeffer M. A., Bergsson, B., Barsotti, S., Stefánsdóttir, G., Galle, B., Arellano, S., et al. (2018), ‘Ground-based measurements of the 2014–2015 Holuhraun volcanic cloud (Iceland)’. Geosciences, 8(1), 29, https://tinyurl.com/pfeffer2018.
Gerlach et al. estimate that the eruption of Mount Pinatubo in 1991 released 42 million tonnes CO2: Gerlach, T.M., Westrich, H.R., and Symonds, R.B. (1996), ‘Preeruption vapor in magma of the climactic Mount Pinatubo eruption: source of the giant stratospheric sulfur dioxide cloud’. In C.G. Newhall and R.S. Punongbayan (eds), Fire and Mud: Eruptions and Lahars of Mount Pinatubo, Philippines. Seattle and London: University of Washington Press, pp.415–433, https://tinyurl.com/gerlach1996
2 Research by the Deep Carbon Observatory programme suggests that volcanic activity releases between 280 and 360 million tonnes CO2 to the atmosphere and oceans every year. This includes active volcanic vents, release through soils, faults and fractures in volcanic regions, volcanic lakes and from the mid-ocean ridge system. They estimate that there are about 400 volcanoes active today. Active eruptions only cause around 2 million tonnes CO2 per year: Deep Carbon Observatory (2019), ‘Scientists quantify global volcanic CO2 venting; estimate total carbon on Earth’. EurekAlert, 1 October, https://tinyurl.com/deep-carbon-obs .
This comes close to the estimate of 300 million tonnes CO2 by the British Geological Survey that I cited in the last edition of this book and is higher than the estimate of 130–230 million tonnes CO2 by the US Geological Survey estimates of just 200 million tonnes: Hards, V. (2005), ‘Volcanic contributions to the global carbon cycle’. British Geological Survey Occasional Publication No. 10 https://nora.nerc.ac.uk/id/eprint/11487/(this link has been updated for the online version of the notes and references); US Geological Survey (2016), ‘Understanding volcanic hazards can save lives’, https://tinyurl.com/usgs2016
3 The sulfur oxide, ash and other particles released by the eruption of Mount Pinatubo is thought to have led to a net cooling of 0.5°C: Scientific American (2009), ‘Are volcanoes or humans harder on the atmosphere?’, 11 February, https://tinyurl.com/sci-amer-volcanoes
4 In their 2019 report, FIFA estimate that the footprint of the 2010 World Cup was 41,400 tonnes CO2e, but excludes the emissions from venues (including stadium construction and energy use in venues) and transport of fans. A 2009 report that did include these came to 2,753,000 tonnes instead, so I went for their figure for the 2010 World Cup. In their estimates for the 2014 and 2018 World Cups, FIFA included these important aspects, as well as merchandise production. If you’ve read the book from the start, you will have gathered already that this list is just the easy bits, and you could happily double the footprint if you were a bit more inclusive. It’s best not to get too bothered on this occasion: Department of Environmental Affairs and Tourism (Republic of South Africa) and the Norwegian Governemnt (NORAD) (2009), ‘Feasibility study for a carbon neutral 2010 FIFA World Cup in South Africa’, https://tinyurl.com/fifa-2010; FIFA (2019), ‘Carbon management and climate protection at FIFA’, https://tinyurl.com/fifa-2019
5 Statistia (2020), ‘Average and total attendance at FIFA football World Cup games 1930–2018’, https://tinyurl.com/statista-fifa, based on Sport.de (2018), ‘WM-Zuschauer: Russland fällt gegenüber Brasilien ab’, 15 July, https://tinyurl.com/sport-fifa
6 FIFA estimates that 3.57 billion people watched at least 1 minute remotely, including live, delayed or repeated screenings and highlights. This includes 3.262 billion TV viewers and 309.7 million viewers online or in public viewings who watched at least 1 minute. In total, it comes to 4.7 viewer-hours: FIFA, ‘Global broadcast and audience summary’, https://tinyurl.com/fifa-audience
7 Willis, R., Berners-Lee, M., Watson, R., and Elm, M. (2020), ‘The case against new coal mines in the UK’. Green Alliance, January, https://bit.ly/37fJTFU
8 Digiconomist estimates that, in 2019, Bitcoin’s electricity demand was 73.1 TWh, which comes in at 46 million tonnes of CO2e, assuming a global electricity mix with a carbon intensity of 0.63 million tonnes CO2e per TWh: Digiconomist (2020), ‘Bitcoin energy consumption index’, https://tinyurl.com/digiconomist-bitcoin.
Bitcoin had a market capitalisation of 68 per cent in January 2020 (https://coinmarketcap.com/charts/), so if we assume that other cryptocurrencies have the same carbon footprint per dollar value, the carbon footprint of all cryptocurrencies would be around 68 million tonnes CO2e.
9 This is out of 55.6 billion tonnes CO2e GHG emissions, including land use change, in 2018: Olivier, J.G.J, and Peters, J.A.H.W. (2019),’Trends in global CO2 and total greenhouse gas emissions: summary of the 2019 report’, 4 December, PBL Netherlands Environmental Assessment Agency, The Hague, https://bit.ly/2W8wuLJ (see The world’s emissions, p.179).
10 According to the International Energy Agency (IEA), global electricity demand was more than 23,000 TWh in 2018: IEA (2019), ‘Global energy & CO2 status report 2019’, https://tinyurl.com/global-electricity.
My figure of 0.32 per cent for Bitcoin’s share of global electricity is very close to Digiconomist’s estimate of 0.33 per cent: Digiconomist (2020), ‘Bitcoin energy consumption index’, https://tinyurl.com/digiconomist-bitcoin
11 Krause and Tolaymat calculated that the amount of electricity required to mine a single coin increased from 1074 kWh in January 2016, to 4577 kWh in January 2017, and 23,157 kWh in January 2018: Krause, M.J., and Tolaymat, T. (2018), ‘Quantification of energy and carbon costs for mining cryptocurrencies’. Nature Sustainability, 1(11), 711–718, https://tinyurl.com/krause2018. Applying a global electricity mix carbon intensity of 0.63kg CO2e per kWh, that is 677kg CO2e, 2,884kg CO2e and 14,559kg CO2e per coin in 2016, 2017 and 2018, respectively.
12 Bendiksen, C., and Gibbons, S. (2019), ‘The Bitcoin mining network —trends, average creation cost, electricity consumption & sources’, CoinShares Research, https://www.academia.edu/85064964/The_Bitcoin_Mining_Network_Trends_Average_Creation_Costs_Electricity_Consumption_and_Sources_June_2019_?f_ri=36059 (this link has been updated for the online version of the notes and references). This report estimates that 73 per cent of Bitcoin mining is powered by renewable energy. It also claims that 65 per cent of global mining happens in China, and 54 per cent in the Chinese province Sichuan. However, China has a higher carbon intensity of electricity than other developed country and, even though Sichuan has hydropower facilities, the energy that can be derived from hydropower is highly seasonal, so that alternative energy sources such as coal are required: de Vries, A. (2019), ‘Renewable energy will not solve Bitcoin’s sustainability problem’. Joule, 3(4), 893–898, https://tinyurl.com/deVries2019
13 Mora et al. argue that, if Bitcoin is taken up similarly to other popular technologies, it could emit almost 23.7 billion tonnes of CO2e between 2017 and 2030, and 1.2 billion tonnes in 2030 alone: Mora, C., Rollins, R.L., Taladay, K., Kantar, M.B., Chock, M.K., et al. (2018), ‘Bitcoin emissions alone could push global warming above 2°C’. Nature Climate Change, 8(11), 931–933, https://tinyurl.com/bitcoin-predictions. However, their methodology and assumptions have been questioned by Masanet et al.: Masanet, E., Shehabi, A., Lei, N., Vranken, H., Koomey, J., and Malmodin, J. (2019), ‘Implausible projections overestimate near-term Bitcoin CO2 emissions’. Nature Climate Change, 9(9), 653–654, https://tinyurl.com/masanet2019
14 Estimates of data centres’ phase electricity use vary between 200 and 300 TWh. At the lower end, the International Energy Agency (2017) estimates that data centres worldwide use 200 TWh in 2020. At the higher end, Andrae (2019) estimates 299 TWh – that would be 126–188 million tonnes CO2e, based on a global average electricity of 0.63 million tonnes CO2e per TWh. There are also higher estimates out there, such as Belkhir and Elmeligi’s (2018) 495 million tonnes in 2020, but Belkhir himself admits that this figure was somewhat overestimated. These figures are based on older data: IEA (2017), ‘Digitalisation and energy’, https://tinyurl.com/iea2017; Andrae, A.S. (2019), ‘Comparison of several simplistic high-level approaches for estimating the global energy and electricity use of ICT networks and data centers’. International Journal, 5, 51, https://www.researchgate.net/profile/Anders_Andrae/publication/336284632_Comparison_of_Several_Simplistic_High-Level_Approaches_for_Estimating_the_Global_Energy_and_Electricity_Use_of_ICT_Networks_and_Data_Centers/links/5d99962592851c2f70eed9a2/Compariso (this link has been updated for the online version of the notes and references); Belkhir, L., and Elmeligi, A. (2018), ‘Assessing ICT global emissions footprint: trends to 2040 & recommendations’. Journal of Cleaner Production, 177, 448–463, https://tinyurl.com/belkhir2018.
The most recent data come from Malmodin and Masanet et al., who estimated that data centres consumed 205 TWh in 2018, equal to 129 million tonnes CO2e assuming global average electricity: Masanet, E., Shehabi, A., Lei, N., Smith, S., and Koomey, J. (2020), ‘Recalibrating global data center energy-use estimates’. Science, 367(6481), 984–986.
In 2020, Jens Malmodin estimated data centres use 230 TWh in 2020, equal to 145 million tonnes CO2e based on global average electricity (personal communication; this is an update to an earlier study from 2018): Malmodin, J., and Lundén, D. (2018), ‘The energy and carbon footprint of the global ICT and E&M sectors 2010–2015’. Sustainability, 10(9), 3027, https://tinyurl.com/Malmodin2018
These figures include electricity used to run and cool the servers and any backup power supplies and operational overheads, but not emissions embodied in the servers and the building. For 2015, Malmodin and Lundén estimated embodied emissions of data centres at 9 million tonnes CO2e. Malmodin’s figure includes electricity used to run and cool the servers and any backup power supplies and operational overheads.
However, they don’t include the emissions embodied in the servers and the building, although they probably only add a small share relative to the use phase emissions. One estimate for embodied emissions in data centres was 9 million tonnes CO2e in 2015 relative to (Malmodin and Lundén, 2018; https://tinyurl.com/Malmodin2018), or 15 million tonnes CO2e when adjusted for truncation error. That’s 10 per cent of total data centre emissions. If that ratio is applied to 2020, I get to an embodied footprint of 16 million tonnes CO2e. Together with the use phase footprint, that’s 161 million tonnes CO2e. This is a very rough estimate.
I assume a global average electricity of 0.63 million tonnes CO2e per TWh here. Some data centre providers buy or generate their own renewable energy, but we don’t know the exact share of renewables. Most of the world’s data centres are located in the US and the second most in the Asia-Pacific region (by number of servers and workload), according to the IEA: IEA (2017), ‘Digitalisation and energy’, https://tinyurl.com/iea2017.
Both areas have higher electricity carbon intensity than the world average. Greenpeace points out that 73 per cent of China’s data centres are powered by coal (https://tinyurl.com/greenpeace2019), that their energy consumption is expected to go up, and that areas where data centres concentrate have one of the lowest shares of renewable energy (https://www.greenpeace.org/static/planet4-international-stateless/2017/01/35f0ac1a-clickclean2016-hires.pdf, this link has been updated for the online version of the notes and references).
15 According to the International Energy Agency, the global electricity demand was more than 23,000 TWh in 2018: IEA (2019), ‘Global energy & CO2 status report 2019’, https://tinyurl.com/global-electricity.
The 1 per cent of global electricity is also backed up by Masanet et al.: Masanet, E., Shehabi, A., Lei, N., Smith, S., and Koomey, J. (2020), ‘Recalibrating global data center energy-use estimates’. Science, 367(6481), 984–986, https://tinyurl.com/masanet2020.
Global GHG emissions were 55.6 billion tonnes CO2e GHG emissions, including land use change, in 2018: Olivier, J.G.J, and Peters, J.A.H.W. (2019),’Trends in global CO2 and total greenhouse gas emissions: summary of the 2019 report’, 4 December, PBL Netherlands Environmental Assessment Agency, The Hague, https://bit.ly/2W8wuLJ
16 It is uncertain what exactly will happen with data centres’ footprint in the future. The demand for more data centre service capacity is continuing to increase. At the same time, efficiency improvements in processor technology are slowing down and Moore’s law is coming to an end: Waldrop, M.M. (2016), ‘The chips are down for Moore’s law’. Nature News, 530(7589), 144, https://tinyurl.com/waldrop2016. Whether efficiency gains, such as those following Moores Law, automatically reduce world emissions as many assume or end up stimulating higher emissions is an important and controversial point.
17 This is an example for Jevons paradox (see p173), where efficiency improvements lead to increased resource use because of rebound effects, and which is explored in: Berners-Lee, M. and Clark, D. (2013), The Burning Question: We Can’t Burn Half the World’s Oil, Coal and Gas. So How Do We Quit? London: Profile Books.
There is also this report by the UK Energy Research Council: Sorrell, S. (2007), ‘The rebound effect: an assessment of the evidence for economy-wide energy savings from improved energy efficiency’. UK Energy Research Centre, https://tinyurl.com/sorrell2007
18 The two top figures are provisional data for 2019 for territorial CO2 and greenhouse gas emissions from the UK’s Office for National Statistics: ONS (2020), ‘Provisional UK greenhouse gas emissions national statistics’, https://tinyurl.com/ons-uk-emissions. The third figure is based on my own modelling, using my input–output model.
19 The data are based on: Ritchie, H., and Roser, M. (2019), ‘CO2 and greenhouse gas emissions: consumption-based (trade-adjusted) CO2 emissions’. Our World in Data, https://tinyurl.com/emissions-by-country
20 Based on data from: Ritchie, H., and Roser, M. (2019), ‘CO2 and greenhouse gas emissions: production vs consumption-based CO2 emissions per capita’. Our World in Data, https://tinyurl.com/emissions-per-capita
21 Tim Jackson’s classic book Prosperity Without Growth, updated in 2017 (Abingdon: Routledge), is a rigorous and accessible articulation of this uncomfortable reality. You can read the original 2009 article for free here: https://tinyurl.com/prosp-without-growth.
I also recommend Kate Raworth’s book Doughnut Economics: Seven Ways to Think Like a 21st-Century Economist, published in 2017 (London: Business Books/Penguin), and her TED-talk ‘A healthy economy should be designed to thrive, not grow’, https://tinyurl.com/raworth-tedtalk
22 Based on consumption-based emissions from Our World In Data, divided by total GDP of each country provided by the World Bank: https://tinyurl.com/world-bank-gdp
Billions of tonnes
1 The data used here were calculated from the Global Fire Emissions Database: www.globalfiredata.org/
2 Paddison, L. (2019) ‘2019 was the year the world burned’, Huffington Post, 27 December, https://tinyurl.com/paddison2019.
3 Nature (2020), ‘Playing with fire could turn the Amazon into a carbon source’, Nature, 10 January, https://go.nature.com/34EAAPe: Brando, P.M., Soares-Filho, B., Rodrigues, L., Assunção, A., Morton, D., Tuchschneider, D., et al. (2020), ‘The gathering firestorm in southern Amazonia’. Science Advances, 6(2), eaay1632, https://tinyurl.com/brando2020
4 In the end (with a lot of help from colleagues) I found that the three most credible studies roughly converged on the same ballpark figure, once they had been adjusted to take account of the different things they excluded and included.
Malmodin and Lundén estimated the carbon footprint of the ICT industry (including data centres, networks and user devices like computers, smartphones and traditional phones) at 730 million tonnes CO2e and an additional 420 million tonnes CO2e for TVs, TV networks and other consumer electronics (such as cameras, projectors, non-smart speakers, portable media players like iPods and game consoles), coming to a total of 1150 million tonnes CO2e. In conversation, Jens Malmodin provided me with his most recent estimates for 2020: 690 million tonnes CO2e in 2020 and a further 400 million tonnes CO2e for TVs, TV networks and other consumer electronics, coming to a total of 1.1 billion CO2e: Malmodin, J., and Lundén, D. (2018), ‘The energy and carbon footprint of the global ICT and E&M sectors 2010–2015’. Sustainability, 10(9), 3027, https://tinyurl.com/Malmodin2018.
Andrae also arrives at 1.1 billion tonnes CO2e for the ICT industry including TV: Andrae, A.S. (2019), ‘Comparison of several simplistic high-level approaches for estimating the global energy and electricity use of ICT networks and data centers’. International Journal, 5, 51, https://www.researchgate.net/profile/Anders_Andrae/publication/336284632_Comparison_of_Several_Simplistic_High-Level_Approaches_for_Estimating_the_Global_Energy_and_Electricity_Use_of_ICT_Networks_and_Data_Centers/links/5d99962592851c2f70eed9a2/Compariso (this link has been updated for the online version of the notes and references).
Belkhir and Elmeligi’s estimates are a bit higher, at between 1.1 and 1.3 billion tonnes CO2e for ICT without TVs: Belkhir, L., and Elmeligi, A. (2018), ‘Assessing ICT global emissions footprint: Trends to 2040 & recommendations’. Journal of Cleaner Production, 177, 448–463, https://tinyurl.com/belkhir2018.
All these estimates include use phase and embodied emissions, but their methodologies incur truncation error (the omission by life cycle analyses of large numbers of small supply chain pathways that are collectively very significant). When this is adjusted for, Malmodin’s (2018) estimate of the ICT’s footprint rises to 870 million tonnes CO2e for data centres, networks and user devices, and 460 million tonnes CO2e for TVs, TV equipment like set-top boxes, TV networks and other consumer electronics, or a total of 1.3 billion tonnes CO2e. Andrae’s (2019) estimate rises to 1.4 billion tonnes CO2e, and Belkhir and Elmeligi’s (2018) estimates rise to 1.5–1.8 billion tonnes CO2e, or 1.9–2.2 billion tonnes CO2e if Malmodin’s figure for TVs, TV networks and consumer electronics is included in their estimate.
I will go with Malmodin’s estimate plus cryptocurrencies (see Cryptocurrencies, p.164), coming to a total of 1.4 billion tonnes CO2e. These estimates include some, but not most, embedded ICT in ‘smart’ devices, including the ‘Internet of things’.
5 Malmodin and Lundén (2018) estimate that 44 per cent of user devices’ footprint in 2015 came from embodied emissions; Belkhir and Elmeligi (2018) estimate between 62 per cent and 64 per cent in 2020. This is particularly pronounced for smartphones, where 85–95 per cent of the footprint is from embodied emissions: Belkhir, L. (2018), ‘How smartphone are heating up the planet’. The Conversation, 25 March, https://tinyurl.com/belkhir-smartphones.
An exception to this rule is set-top boxes and routers, because mostly people leave them on 24/7. My own analysis suggests that the majority of computers’ (p.129), smartphones’ (p.116) and TVs’ (p.43) footprint is embodied.
6 William Stanley Jevons (1865), The Coal Question. Jevons pointed out that more efficiency would make coal more attractive and would increase demand rather than reduce it. I have written about this in There Is No Planet B (2019), which is in many ways a companion to Bananas, and before that, with Duncan Clark, even more extensively, in The Burning Question (2013).
7 The atomic bomb dropped on Hiroshima in 1945 had an explosive energy of 15 kilotonnes of TNT equivalent: Atomic Heritage Foundation (2014), ‘Little Boy and Fat Man’, https://tinyurl.com/hiroshima-bomb
8 Based on a conversion factor of $1 = £0.81 at the time of writing. I’m using estimates of total spend and multiplying these by the carbon intensity per £1 spend of the UK’s defence sector of 0.235 kg CO2e per £1 based on my input–output model, but I multiply it by 1.5 for the US and 2.3 for the world because their economy is that much more carbon intensive in terms of CO2 per $ GDP (see p.167 for the UK’s and US’s carbon intensity per $). For the world, this is based on 35.7 million tonnes CO2 in 2016 according to Our World In Data (https://tinyurl.com/annual-co2) and 76 trillion $ GDP based on the World Bank (https://tinyurl.com/world-bank-gdp).
9 Neta Crawford, co-director of the The Cost of War Project by the Watson Institute at Brown University, estimates US spending on the Iraq War at $1922 billion: Crawford, N.C. (2020), ‘The Iraq war has cost the US nearly $2 trillion’. Defense One, 4 February, https://tinyurl.com/crawford-2020
10 The Stockholm International Peace Research Institute estimates that the US spent $730 billion in 2019 on defence, while the world total spend on defence was $1910 billion. The UK spend is estimated at $49 billion:Tian, N., Kuimova, A., Da Silva, D.L., Wezeman, P.D., and Wezeman, S.T. (2020), ‘Trends in world military expenditure, 2019’. Stockholm International Peace Research Institute, https://tinyurl.com/tian2020
11 The Cost of War Project by the Watson Institute at Brown University has estimated the US military’s footprint for the fiscal years 2001–2018 and concluded that the US Department of Defense is ‘the world’s largest institutional user of petroleum and correspondingly, the single largest institutional producer of greenhouse gases (GHG) in the world’: Crawford, N. (2019), ‘Pentagon fuel use, climate change, and the costs of war’. Watson Institute for International & Public Affairs, Brown University,https://tinyurl.com/crawford-2019
12 There is a worrying trend in the Syrian War for attacks to focus on hospitals. This does not only increase suffering and defy international humanitarian law, but it means that the destroyed facilities need to be rebuilt, which comes at a carbon cost:
Koteiche, R. (2019), ‘Destroying hospitals to win the war’. Physicians for Human Rights, 21 May, https://tinyurl.com/koteiche2019
13 Stuart Parkinson from Scientists for Global Responsibility estimates that the global military footprint might be 5 per cent of global emissions and another 1 per cent for war impacts in 2018. Of the 55.6 billion tonnes CO2e emitted in 2018, that’s 3.3 billion tonnes: Parkinson, S. (2019), ‘The carbon bootprint of the military’, 29 June, https://tinyurl.com/parkinson-2019
14 Jacobson, M.Z. (2009), ‘Review of solutions to global warming, air pollution, and energy security’. Energy & Environmental Science, 2(2), 148–173, https://tinyurl.com/jacobson2009
15 This article in Nature summarises several recent studies on this topic: Witze, A. (2020), ‘How a small nuclear war would transform the entire planet’. Nature, 579(7800), 485-487, https://tinyurl.com/witze2020.
The figure for a regional nuclear war comes from: Toon, O.B., Bardeen, C.G., Robock, A., Xia, L., Kristensen, H., McKinzie, M., et al. (2019), ‘Rapidly expanding nuclear arsenals in Pakistan and India portend regional and global catastrophe’. Science Advances, 5(10), eaay5478, https://tinyurl.com/toon2019.
A regional conflict could cause 16–36 million tonnes of black carbon to be released and lead to a cooling of the climate by 2°C to 5°C globally. There would also be 50 to 125 million deaths.
The estimate for a nuclear war between Russia and the US comes from: Robock, A., Oman, L., and Stenchikov, G.L. (2007), ‘Nuclear winter revisited with a modern climate model and current nuclear arsenals: still catastrophic consequences’. Journal of Geophysical Research: Atmospheres, 112(D13), https://tinyurl.com/robock2007. A US–Russia nuclear war could release 150 million tonnes of black carbon and lead to a 10°C drop in global temperatures.
16 Klare, M.T. (2020), ‘How rising temperatures increase the likelihood of nuclear war’. The Nation, 13 January, https://tinyurl.com/klare2020. The effect of climate change on agriculture, competition for the polar waters and the frequency of natural disasters could fuel international conflicts and increase the risk of a nuclear war.
17 Watson, J.E., Evans, T., Venter, O., Williams, B., Tulloch, A., Stewart, C., et al. (2018), ‘The exceptional value of intact forest ecosystems’. Nature Ecology & Evolution, 2(4), 599–610, https://tinyurl.com/watson2018-forests
18 UN REDD Programme (2019), ‘Forest facts’, www.un-redd.org/forest-facts (since the release of the book this source is no longer available online. An additional source quoting the same figure is available here: https://www.fao.org/newsroom/detail/REDD-North-South-Agreement-for-New-Emissions-Reduction-Mechanism/en).
19 Curtis, P. G., Slay, C. M., Harris, N. L., Tyukavina, A., and Hansen, M.C. (2018), ‘Classifying drivers of global forest loss’. Science, 361(6407), 1108–1111, https://tinyurl.com/curtis-2018
20 Woodland Carbon Code (2018), ‘Woodland carbon calculation spreadsheet’, https://tinyurl.com/woodland-carbon
21 Gov.uk Guidance (2019), ‘Woodland carbon guarantee’, https://tinyurl.com/woodland-guarantee
22 Bond, T.C., Doherty, S.J., Fahey, D.W., Forster, P.M., Berntsen, T., DeAngelo, B.J., et al. (2013), ‘Bounding the role of black carbon in the climate system: a scientific assessment’. Journal of Geophysical Research: Atmospheres, 118(11), 5380–5552, https://tinyurl.com/bond-2013
23 Bond, T.C., Doherty, S.J., Fahey, D.W., Forster, P.M., Berntsen, T., DeAngelo, B.J., et al. (2013), ‘Bounding the role of black carbon in the climate system: a scientific assessment’. Journal of Geophysical Research: Atmospheres, 118(11), 5380–5552, https://tinyurl.com/bond-2013
24 Timonen, H., Karjalainen, P., Aalto, P., Saarikoski, S., Mylläri, F., Karvosenoja, N., et al. (2019), ‘Adaptation of black carbon footprint concept would accelerate mitigation of global warming’. Environmental Science & Technology, 53, 12153–12155, https://tinyurl.com/timonen2019
25 Timonen, H., Karjalainen, P., Aalto, P., Saarikoski, S., Mylläri, F., Karvosenoja, N., et al. (2019), ‘Adaptation of black carbon footprint concept would accelerate mitigation of global warming’. Environmental Science & Technology, 53, 12153–12155, https://tinyurl.com/timonen2019
26 Lund, M.T., Samset, B.H., Skeie, R.B., Watson-Parris, D., Katich, J.M., et al. (2018), ‘Short black carbon lifetime inferred from a global set of aircraft observations’. npj Climate and Atmospheric Science, 1(1), 1–8, https://tinyurl.com/lund-2018
27 Bond, T.C., Doherty, S.J., Fahey, D.W., Forster, P.M., Berntsen, T., DeAngelo, B.J., et al. (2013), ‘Bounding the role of black carbon in the climate system: a scientific assessment’. Journal of Geophysical Research: Atmospheres, 118(11), 5380–5552, https://tinyurl.com/bond-2013.
There are other estimates of the mass of black carbon released every year and its global warming potential, such as by the Climate and Clean Air Coalition (https://tinyurl.com/ccacoalition), who estimate emissions at 6.6 million tonnes in 2015 and cite a global warming potential of 460–1500 but on average they also arrive at 6.5 billion tonnes CO2e, not too far off the estimate of 8.8 billion.
28 Data for 2018 from Olivier and Peters and the Global Carbon Project, Global Carbon Project. I’ve used a mark-up factor of 1.9 for high-altitude emissions, as suggested by BEIS, and approximated aviation emissions at 2 per cent of CO2 without that: Olivier, J.G.J, and Peters, J.A.H.W. (2019),’Trends in global CO2 and total greenhouse gas emissions: summary of the 2019 report’, 4 December, PBL Netherlands Environmental Assessment Agency, The Hague, https://bit.ly/2W8wuLJ; Global Carbon Project (2019), https://essd.copernicus.org/articles/11/1783/2019/ (this link has been updated for the online version of the notes and references, for more recent data see also https://www.globalcarbonproject.org/).
29 The UN’s Emissions Gap Report 2019 concluded that ‘There is no sign of GHG emissions peaking in the next few years; every year of postponed peaking means that deeper and faster cuts will be required’: UN Environment Programme (2019), ‘Emissions gap report 2019’. UNEP, https://tinyurl.com/emission-gap
30 Nobody knows exactly how much fuel there is in the ground, so these numbers are estimates. The proven reserves come from BP’s Statistical Review of World Energy 2019, https://tinyurl.com/bp-review2019.
The figures for unconventional fuels like tar sands come from: Centre for Sustainable Systems (2019), ‘Unconventional fossil fuels factsheet’. University of Michigan, https://tinyurl.com/unconv-fossil.
Up-to-date data on recoverable resources was hard to come by, so I have fallen back on an old source: IEA (2012), ‘World energy outlook 2012’, https://tinyurl.com/iea-2012.
This is the same source that Duncan Clark and I used in The Burning Question (Profile Books, 2013), which covers the abundance of fossil fuel in a lot more detail.
1 Bastin, J.F., Finegold, Y., Garcia, C., Mollicone, D., Rezende, M., Routh, D., et al. (2019), ‘The global tree restoration potential’. Science, 365(6448), 76–79, https://tinyurl.com/bastin2019
2 Veldman, J.W., Aleman, J.C., Alvarado, S.T., Anderson, T.M., Archibald, S., Bond, W.J., et al. (2019), ‘Comment on “The global tree restoration potential”’. Science, 366(6463), eaay7976, https://tinyurl.com/veldman2019
3 Oreska, M.P., McGlathery, K.J., Aoki, L.R., Berger, A.C., Berg, P., and Mullins, L. (2020), ‘The greenhouse gas offset potential from seagrass restoration’. Scientific Reports, 10(1), 1–15, https://tinyurl.com/oreska2020
4 This is an estimate based on data from Duarte et al. (2013), which estimates that current global carbon storage for marine vegetation is 19.65 billion tonnes (3.45, 9.9 and 6.3 billion tonnes of carbon storage for salt marshes, mangroves and seagrasses respectively) and roughly 35 per cent losses in marine vegetation since the Second World War (25 per cent for salt marshes, 40 per cent for mangroves and 30 per cent for seagrasses), which adds up to around 10 billion tonnes of carbon lost, or 37 billion tonnes CO2e: Duarte, C.M., Losada, I.J., Hendriks, I.E., Mazarrasa, I., and Marbà, N. (2013), ‘The role of coastal plant communities for climate change mitigation and adaptation’. Nature Climate Change, 3(11), 961–968, https://tinyurl.com/duarte2013
5 Sanderman, J., Hengl, T., and Fiske, G. J. (2017), ‘Soil carbon debt of 12,000 years of human land use’. Proceedings of the National Academy of Sciences, 114(36), 9575–9580, https://tinyurl.com/sanderman2017
6 Amundson, R., and Biardeau, L. (2018), ‘Opinion: soil carbon sequestration is an elusive climate mitigation tool’. Proceedings of the National Academy of Sciences, 115(46), 11652–11656, https://tinyurl.com/amundson2018
7 Brownsport, P., Carter, S., Cook, J., Cunningham, C., Gaunt, J., Hammond, J., et al. (2010), ‘An assessment of the benefits and issues associated with the application of biochar to soil’. Defra, https://pure.manchester.ac.uk/ws/portalfiles/portal/32910433/FULL_TEXT.PDF (this link has been updated for the online version of the notes and references).
8 Paustian, K., Lehmann, J., Ogle, S., Reay, D., Robertson, G.P., and Smith, P. (2016), ‘Climate-smart soils’. Nature, 532(7597), 49–57, https://tinyurl.com/paustian2016
9 Psarras, P., Krutka, H., Fajardy, M., Zhang, Z., Liguori, S., Dowell, N.M., and Wilcox, J. (2017), ‘Slicing the pie: how big could carbon dioxide removal be?’ Wiley Interdisciplinary Reviews: Energy and Environment, 6(5), e253, https://tinyurl.com/psarras2017
10 Moosdorf, N., Renforth, P., and Hartmann, J. (2014), ‘Carbon dioxide efficiency of terrestrial enhanced weathering’. Environmental Science & Technology, 48(9), 4809–4816, https://tinyurl.com/moosdorf2014, doi:10.1088/1748-9326/aaa9c4; Strefler, J., Amann, T., Bauer, N., Kriegler, E., and Hartmann, J. (2018), ‘Potential and costs of carbon dioxide removal by enhanced weathering of rocks’. Environmental Research Letters, 13(3), 034010, https://tinyurl.com/strefler2018
11 Strefler, J., Amann, T., Bauer, N., Kriegler, E., and Hartmann, J. (2018), ‘Potential and costs of carbon dioxide removal by enhanced weathering of rocks’. Environmental Research Letters, 13(3), 034010, https://tinyurl.com/strefler2018. Thanks also to Chris Goodall and his excellent weekly Carbon Commentary newsletter for this (an excellent source of low-carbon technology updates with free subscription), www.carboncommentary.com/
12 Psarras, P., Krutka, H., Fajardy, M., Zhang, Z., Liguori, S., Dowell, N.M., and Wilcox, J. (2017), ‘Slicing the pie: how big could carbon dioxide removal be?’ Wiley Interdisciplinary Reviews: Energy and Environment, 6(5), e253, https://tinyurl.com/psarras2017