Offsetting unabated agricultural emissions with CO2 removal to achieve ambitious climate targets

to eradicate poverty. 2018. Available: https://www.ipcc.ch/site/assets/uploads/sites/2/2019/06/SR15_ Full_Report_High_Res.pdf 2. Shoemaker JK, Schrag DP, Molina MJ, Ramanathan V. What Role for Short-Lived Climate Pollutants in Mitigation Policy? Science. 2013; 342: 1323–1324. https://doi.org/10.1126/science.1240162 PMID: 24337280 3. IPCC. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Geneva, Switzerland: Inter- governmental Panel for Climate Change; 2014 p. 151. Available: https://www.ipcc.ch/report/ar5/syr/ 4. Mbow, C., C., Rosenzweig, L.G., Barioni LG. Chapter 5: Food Security—Special Report on Climate Change and Land. 2019. Available: https://www.ipcc.ch/srccl/chapter/chapter-5/ 5. Rosenzweig C, Mbow C, Barioni LG, Benton TG, Herrero M, Krishnapillai M, et al. Climate change responses benefit from a global food system approach. Nat Food. 2020; 1: 94–97. https://doi.org/10. 1038/s43016-020-0031-z 6. Gernaat DEHJ, Calvin K, Lucas PL, Luderer G, Otto SAC, Rao S, et al. Understanding the contribution of non-carbon dioxide gases in deep mitigation scenarios. Glob Environ Change. 2015; 33: 142–153. https://doi.org/10.1016/j.gloenvcha.2015.04.010 7. Popp A, Calvin K, Fujimori S, Havlik P, Humpeno¨ der F, Stehfest E, et al. Land-use futures in the shared socio-economic pathways. Glob Environ Change. 2017; 42: 331–345. https://doi.org/10.1016/j. gloenvcha.2016.10.002

8. Rogelj J, Forster PM, Kriegler E, Smith CJ, Se´ fe´ rian R. Estimating and tracking the remaining carbon budget for stringent climate targets. Nature. 2019; 571: 335–342. https://doi.org/10.1038/s41586-019- 1368-z PMID: 31316194 9. Karakurt I, Aydin G, Aydiner K. Sources and mitigation of methane emissions by sectors: A critical review. Renew Energy. 2012; 39: 40–48. https://doi.org/10.1016/j.renene.2011.09.006 10. Gerber PJ, Steinfeld H, Henderson B, Mottet A, Opio C, Dijkman J, et al. Tackling climate change through livestock: a global assessment of emissions and mitigation opportunities. Rome: Food and Agriculture Organization of the United Nations; 2013. 11. Wollenberg E, Richards M, Smith P, Havlı´k P, Obersteiner M, Tubiello FN, et al. Reducing emissions from agriculture to meet the 2˚C target. Glob Change Biol. 2016; 22: 3859–3864. https://doi.org/10. 1111/gcb.13340 PMID: 27185416 12. Tubiello FN, Salvatore M, Condor Golec RD, Ferrara A, Rossi S, Biancalani R, et al. Agriculture, forestry and other land use emissions by sources and removals by sinks. Food and Agriculture Organization of the United Nations; 2014. 13. Montzka SA, Dlugokencky EJ, Butler JH. Non-CO2 greenhouse gases and climate change. Nature. 2011; 476: 43–50. https://doi.org/10.1038/nature10322 PMID: 21814274 14. Bajzˇelj B, Richards KS, Allwood JM, Smith P, Dennis JS, Curmi E, et al. Importance of food-demand management for climate mitigation. Nat Clim Change. 2014; 4: 924–929. https://doi.org/10.1038/ nclimate2353

15. Leahy S, Clark H, Reisinger A. Challenges and Prospects for Agricultural Greenhouse Gas Mitigation Pathways Consistent With the Paris Agreement. Front Sustain Food Syst. 2020; 4. https://doi.org/10. 3389/fsufs.2020.00097 PMID: 33073178 16. Bennetzen EH, Smith P, Porter JR. Decoupling of greenhouse gas emissions from global agricultural production: 1970–2050. Glob Change Biol. 2016; 22: 763–781. https://doi.org/10.1111/gcb.13120 PMID: 26451699 17. Frank S, Havlı´k P, Stehfest E, Meijl H van, Witzke P, Pe´ rez-Domı´nguez I, et al. Agricultural non-CO 2 emission reduction potential in the context of the 1.5˚C target. Nat Clim Change. 2019; 9: 66–72. https:// doi.org/10.1038/s41558-018-0358-8 18. FAO. The future of food and agriculture—Alternative pathways to 2050. Rome, Italy: Food and Agricul- ture Organization of the United Nations; 2018. Available: http://www.fao.org/3/CA1553EN/ca1553en. pdf 19. Huppmann D, Rogelj J, Kriegler E, Krey V, Riahi K. A new scenario resource for integrated 1.5˚C research. Nat Clim Change. 2018; 8: 1027–1030. https://doi.org/10.1038/s41558-018-0317-4 20. Springmann M, Godfray HCJ, Rayner M, Scarborough P. Analysis and valuation of the health and cli- mate change cobenefits of dietary change. Proc Natl Acad Sci. 2016; 113: 4146–4151. https://doi.org/ 10.1073/pnas.1523119113 PMID: 27001851 21. Stehfest E, Bouwman L, van Vuuren DP, den Elzen MGJ, Eickhout B, Kabat P. Climate benefits of changing diet. Clim Change. 2009; 95: 83–102. https://doi.org/10.1007/s10584-008-9534-6 PLOS ONE Offsetting future agricultural emissions with CO2 removal

PLOS ONE | https://doi.org/10.1371/journal.pone.0247887 March 17, 2021 15 / 19

22. Herrero M, Henderson B, Havlı´k P, Thornton PK, Conant RT, Smith P, et al. Greenhouse gas mitigation potentials in the livestock sector. Nat Clim Change. 2016; 6: 452–461. https://doi.org/10.1038/ nclimate2925 23. Frank S, Beach R, Havlı´k P, Valin H, Herrero M, Mosnier A, et al. Structural change as a key component for agricultural non-CO 2 mitigation efforts. Nat Commun. 2018; 9: 1–8. https://doi.org/10.1038/s41467- 017-02088-w PMID: 29317637 24. Pradhan P, Reusser DE, Kropp JP. Embodied Greenhouse Gas Emissions in Diets. PLOS ONE. 2013; 8: e62228. https://doi.org/10.1371/journal.pone.0062228 PMID: 23700408 25. Monteiro CA, Pfeiler TM, Patterson MD, Milburn MA. The Carnism Inventory: Measuring the ideology of eating animals. Appetite. 2017; 113: 51–62. https://doi.org/10.1016/j.appet.2017.02.011 PMID: 28189749 26. Hartmann C, Siegrist M. Our daily meat: Justification, moral evaluation and willingness to substitute. Food Qual Prefer. 2020; 80: 103799. https://doi.org/10.1016/j.foodqual.2019.103799 27. Hartmann C, Siegrist M. Consumer perception and behaviour regarding sustainable protein consump- tion: A systematic review. Trends Food Sci Technol. 2017; 61: 11–25. https://doi.org/10.1016/j.tifs. 2016.12.006 28. Wirsenius S, Hedenus F, Mohlin K. Greenhouse gas taxes on animal food products: rationale, tax scheme and climate mitigation effects. Clim Change. 2011; 108: 159–184. https://doi.org/10.1007/ s10584-010-9971-x 29. Fesenfeld LP, Wicki M, Sun Y, Bernauer T. Policy packaging can make food system transformation fea-

sible. Nat Food. 2020; 1: 173–182. https://doi.org/10.1038/s43016-020-0047-4 30. Frank S, Havlı´k P, Soussana J-F, Levesque A, Valin H, Wollenberg E, et al. Reducing greenhouse gas emissions in agriculture without compromising food security? Environ Res Lett. 2017; 12: 105004. https://doi.org/10.1088/1748-9326/aa8c83 31. Fujimori S, Hasegawa T, Rogelj J, Su X, Havlik P, Krey V, et al. Inclusive climate change mitigation and food security policy under 1.5\hspace0.167em˚C climate goal. Environ Res Lett. 2018; 13: 074033. https://doi.org/10.1088/1748-9326/aad0f7 32. Bertram C, Luderer G, Popp A, Minx JC, Lamb WF, Stevanović M, et al. Targeted policies can compen- sate most of the increased sustainability risks in 1.5˚C mitigation scenarios. Environ Res Lett. 2018; 13: 064038. https://doi.org/10.1088/1748-9326/aac3ec 33. Rogelj J, Shindell D, Jiang K, Fifita S, Forster P, Ginzburg V, et al. Mitigation Pathways Compatible with 1.5˚C in the Context of Sustainable Development. Geneva, Switzerland: Intergovernmental Panel for Climate Change; 2018 p. 82. 34. Rogelj J, Reisinger A, McCollum DL, Knutti R, Riahi K, Meinshausen M. Mitigation choices impact car- bon budget size compatible with low temperature goals. Environ Res Lett. 2015; 10: 075003. https://doi. org/10.1088/1748-9326/10/7/075003 35. Allen MR, Fuglestvedt JS, Shine KP, Reisinger A, Pierrehumbert RT, Forster PM. New use of global warming potentials to compare cumulative and short-lived climate pollutants. Nat Clim Change. 2016; 6: 773–776. https://doi.org/10.1038/nclimate2998

36. Fuss S, Lamb WF, Callaghan MW, Hilaire J, Creutzig F, Amann T, et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ Res Lett. 2018; 13: 063002. https://doi.org/10.1088/1748- 9326/aabf9f 37. Parker A, Geden O. No fudging on geoengineering. Nat Geosci. 2016; 9: 859–860. https://doi.org/10. 1038/ngeo2851 38. Anderson K, Peters G. The trouble with negative emissions. Science. 2016; 354: 182–183. https://doi. org/10.1126/science.aah4567 PMID: 27738161 39. Nemet GF, Callaghan MW, Creutzig F, Fuss S, Hartmann J, Hilaire J, et al. Negative emissions—Part 3: Innovation and upscaling. Environ Res Lett. 2018; 13: 063003. https://doi.org/10.1088/1748-9326/ aabff4 40. Low S, Scha¨fer S. Is bio-energy carbon capture and storage (BECCS) feasible? The contested authority of integrated assessment modeling. Energy Res Soc Sci. 2020; 60: 101326. https://doi.org/10.1016/j. erss.2019.101326 41. Low S, Honegger M. A Precautionary Assessment of Systemic Projections and Promises From Sunlight Reflection and Carbon Removal Modeling. Risk Anal. 2020;n/a. https://doi.org/10.1111/risa.13565 PMID: 32722874 42. Reynolds JL. The politics and governance of negative emissions technologies. Glob Sustain. 2018; 1. https://doi.org/10.1017/sus.2018.13 PLOS ONE Offsetting future agricultural emissions with CO2 removal PLOS ONE | https://doi.org/10.1371/journal.pone.0247887 March 17, 2021 16 / 19

43. Honegger M, Reiner D. The political economy of negative emissions technologies: consequences for international policy design. Clim Policy. 2018; 18: 306–321. https://doi.org/10.1080/14693062.2017. 1413322 44. Lomax G, Workman M, Lenton T, Shah N. Reframing the policy approach to greenhouse gas removal technologies. Energy Policy. 2015; 78: 125–136. https://doi.org/10.1016/j.enpol.2014.10.002 45. Meadowcroft J. Exploring negative territory Carbon dioxide removal and climate policy initiatives. Clim Change. 2013; 118: 137–149. https://doi.org/10.1007/s10584-012-0684-1 46. Pearse R, Bo¨hm S. Ten reasons why carbon markets will not bring about radical emissions reduction. Carbon Manag. 2014; 5: 325–337. https://doi.org/10.1080/17583004.2014.990679 47. Common metrics | UNFCCC. [cited 25 Nov 2020]. Available: https://unfccc.int/process-and-meetings/ transparency-and-reporting/methods-for-climate-change-transparency/common-metrics 48. Smith SJ, Wigley ML. Global Warming Potentials: 1. Climatic Implications of Emissions Reductions. Clim Change. 2000; 44: 445–457. https://doi.org/10.1023/A:1005584914078 49. Fuglestvedt JS, Berntsen TK, Godal O, Sausen R, Shine KP, Skodvin T. Metrics of Climate Change: Assessing Radiative Forcing and Emission Indices. Clim Change. 2003; 58: 267–331. https://doi.org/ 10.1023/A:1023905326842 50. Shine KP. The global warming potential—the need for an interdisciplinary retrial. Clim Change. 2009; 96: 467–472. https://doi.org/10.1007/s10584-009-9647-6

51. Pierrehumbert R t. Short-Lived Climate Pollution. Annu Rev Earth Planet Sci. 2014; 42: 341–379. https://doi.org/10.1146/annurev-earth-060313-054843 52. Denison S, Forster PM, Smith CJ. Guidance on emissions metrics for nationally determined contribu- tions under the Paris Agreement. Environ Res Lett. 2019; 14: 124002. https://doi.org/10.1088/1748- 9326/ab4df4 53. The Kyoto Protocol: CO2 CH4 and climate implications—Wigley—1998—Geophysical Research Let- ters—Wiley Online Library. [cited 5 Dec 2020]. Available: https://agupubs.onlinelibrary.wiley.com/doi/ abs/10.1029/98GL01855 54. Shine KP, Fuglestvedt JS, Hailemariam K, Stuber N. Alternatives to the Global Warming Potential for Comparing Climate Impacts of Emissions of Greenhouse Gases. Clim Change. 2005; 68: 281–302. https://doi.org/10.1007/s10584-005-1146-9 55. Allen MR, Shine KP, Fuglestvedt JS, Millar RJ, Cain M, Frame DJ, et al. A solution to the misrepresenta- tions of CO 2 -equivalent emissions of short-lived climate pollutants under ambitious mitigation. Npj Clim Atmospheric Sci. 2018; 1: 1–8. https://doi.org/10.1038/s41612-018-0026-8 56. Huntingford C, Lowe JA, Howarth N, Bowerman NHA, Gohar LK, Otto A, et al. The implications of car- bon dioxide and methane exchange for the heavy mitigation RCP2.6 scenario under two metrics. Envi- ron Sci Policy. 2015; 51: 77–87. https://doi.org/10.1016/j.envsci.2015.03.013 57. Lauder AR, Enting IG, Carter JO, Clisby N, Cowie AL, Henry BK, et al. Offsetting methane emissions—

An alternative to emission equivalence metrics. Int J Greenh Gas Control. 2013; 12: 419–429. https:// doi.org/10.1016/j.ijggc.2012.11.028 58. Edjabou LD, Smed S. The effect of using consumption taxes on foods to promote climate friendly diets– The case of Denmark. Food Policy. 2013; 39: 84–96. https://doi.org/10.1016/j.foodpol.2012.12.004 59. van Vuuren DP, Stehfest E, den Elzen MGJ, Kram T, van Vliet J, Deetman S, et al. RCP2.6: exploring the possibility to keep global mean temperature increase below 2˚C. Clim Change. 2011; 109: 95. https://doi.org/10.1007/s10584-011-0152-3 60. Riahi K, van Vuuren DP, Kriegler E, Edmonds J, O’Neill BC, Fujimori S, et al. The Shared Socioeco- nomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview. Glob Environ Change. 2017; 42: 153–168. https://doi.org/10.1016/j.gloenvcha.2016.05.009 61. van Vuuren DP, Stehfest E, Gernaat DEHJ, Doelman JC, van den Berg M, Harmsen M, et al. Energy, land-use and greenhouse gas emissions trajectories under a green growth paradigm. Glob Environ Change. 2017; 42: 237–250. https://doi.org/10.1016/j.gloenvcha.2016.05.008 62. Gidden MJ, Riahi K, Smith SJ, Fujimori S, Luderer G, Kriegler E, et al. Global emissions pathways under different socioeconomic scenarios for use in CMIP6: a dataset of harmonized emissions trajecto- ries through the end of the century. Geosci Model Dev. 2019; 12: 1443–1475. https://doi.org/10.5194/ gmd-12-1443-2019 63. Rogelj J, Popp A, Calvin KV, Luderer G, Emmerling J, Gernaat D, et al. Scenarios towards limiting

global mean temperature increase below 1.5˚C. Nat Clim Change. 2018; 8: 325–332. https://doi.org/10. 1038/s41558-018-0091-3 64. Millar RJ, Nicholls ZR, Friedlingstein P, Allen MR. A modified impulse-response representation of the global near-surface air temperature and atmospheric concentration response to carbon dioxide emis- sions. Atmospheric Chem Phys. 2017; 17: 7213–7228. https://doi.org/10.5194/acp-17-7213-2017 PLOS ONE Offsetting future agricultural emissions with CO2 removal PLOS ONE | https://doi.org/10.1371/journal.pone.0247887 March 17, 2021 17 / 19

65. Smith CJ, Forster PM, Allen M, Leach N, Millar RJ, Passerello GA, et al. FAIR v1.1: A simple emis- sions-based impulse response and carbon cycle model. Climate and Earth System Modeling; 2017 Dec. https://doi.org/10.5194/gmd-2017-266 66. Forster D, Huppmann D, Kriegler E, Mundaca L, Smith C, Rogelj J, et al. Mitigation Pathways Compati- ble with 1.5˚C in the Context of Sustainable Development Supplementary Material. Global warming of 15˚C An IPCC Special Report on the impacts of global warming of 15˚C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. 2018. Avail- able: https://www.ipcc.ch/site/assets/uploads/sites/2/2018/12/2SM_V19_for_web.pdf 67. Thompson DWJ, Barnes EA, Deser C, Foust WE, Phillips AS. Quantifying the Role of Internal Climate Variability in Future Climate Trends. J Clim. 2015; 28: 6443–6456. https://doi.org/10.1175/JCLI-D-14- 00830.1 68. Opio C, Gerber P, Mottet A, Falcucci A, Tempio G, MacLeod M, et al. Greenhouse gas emissions from ruminant supply chains–a global life cycle assessment. Food and Agriculture Organization of the United Nations; 2013. Available: https://pure.sruc.ac.uk/en/publications/greenhouse-gas-emissions-from- ruminant-supply-chains-a-global-lif 69. Brodt S, Kendall A, Mohammadi Y, Arslan A, Yuan J, Lee I-S, et al. Life cycle greenhouse gas emis- sions in California rice production. Field Crops Res. 2014; 169: 89–98. https://doi.org/10.1016/j.fcr.

2014.09.007 70. USDA. USDA ERS—Meat Price Spreads. 2020 [cited 2 Jun 2020]. Available: https://www.ers.usda. gov/data-products/meat-price-spreads/ 71. U.S. Bureau of Labor Statistics. Average Retail Food and Energy Prices, U.S. and Midwest Region: Mid–Atlantic Information Office: U.S. Bureau of Labor Statistics. 2020 [cited 17 Jun 2020]. Available: https://www.bls.gov/regions/mid-atlantic/data/AverageRetailFoodAndEnergyPrices_USandMidwest_ Table.htm 72. World Bank. Commodity Markets. In: World Bank [Internet]. 2020 [cited 2 Dec 2020]. Available: https:// www.worldbank.org/en/research/commodity-markets 73. Export Action Global. Dairy Systems Around The World. 2018 [cited 2 Dec 2020]. Available: https:// www.exportactionglobal.com/wp-content/uploads/2018/04/Dairy-Systems-Around-The-World_Export- Action-Global_April-2018.pdf 74. Schewe J, Heinke J, Gerten D, Haddeland I, Arnell NW, Clark DB, et al. Multimodel assessment of water scarcity under climate change. Proc Natl Acad Sci. 2014; 111: 3245–3250. https://doi.org/10. 1073/pnas.1222460110 PMID: 24344289 75. Fuglestvedt JS, Berntsen TK, Godal O, Skodvin T. Climate implications of GWP-based reductions in greenhouse gas emissions. Geophys Res Lett. 2000; 27: 409–412. https://doi.org/10.1029/ 1999GL010939 76. Reisinger A, Clark H. How much do direct livestock emissions actually contribute to global warming? Glob Change Biol. 2018; 24: 1749–1761. https://doi.org/10.1111/gcb.13975 PMID: 29105912 77. Cain M, Lynch J, Allen MR, Fuglestvedt JS, Frame DJ, Macey AH. Improved calculation of warming-

equivalent emissions for short-lived climate pollutants. Npj Clim Atmospheric Sci. 2019; 2: 1–7. https:// doi.org/10.1038/s41612-019-0086-4 PMID: 31656858 78. Lynch J, Cain M, Pierrehumbert R, Allen M. Demonstrating GWP\ast: a means of reporting warming- equivalent emissions that captures the contrasting impacts of short- and long-lived climate pollutants. Environ Res Lett. 2020; 15: 044023. https://doi.org/10.1088/1748-9326/ab6d7e PMID: 32395177 79. Harrison RM, Hester RE. Geoengineering of the Climate System. Royal Society of Chemistry; 2014. 80. Kubo M, Purevdorj M. THE FUTURE OF RICE PRODUCTION AND CONSUMPTION. In: Journal of Food Distribution Research [Internet]. 2004 [cited 14 Jul 2020] pp. 128–142. https://doi.org/10.22004/ ag.econ.27145 81. Banerjee AV, Duflo E. The Economic Lives of the Poor. J Econ Perspect. 2007; 21: 141–168. https:// doi.org/10.1257/jep.21.1.141 PMID: 19212450 82. Iqbal MZ. The Effects of a Large Rice Price Increase on Household Welfare and Poverty in Rural Ban- gladesh. Econ Bull. 2019; 39: 295–309. 83. Oswald Y, Owen A, Steinberger JK. Large inequality in international and intranational energy footprints between income groups and across consumption categories. Nat Energy. 2020; 5: 231–239. https://doi. org/10.1038/s41560-020-0579-8 84. Dennig F, Budolfson MB, Fleurbaey M, Siebert A, Socolow RH. Inequality, climate impacts on the future poor, and carbon prices. Proc Natl Acad Sci. 2015; 112: 15827–15832. https://doi.org/10.1073/pnas. 1513967112 PMID: 26644560 PLOS ONE Offsetting future agricultural emissions with CO2 removal

PLOS ONE | https://doi.org/10.1371/journal.pone.0247887 March 17, 2021 18 / 19

85. Markkanen S, Anger-Kraavi A. Social impacts of climate change mitigation policies and their implica- tions for inequality. Clim Policy. 2019; 19: 827–844. https://doi.org/10.1080/14693062.2019.1596873 86. Smith P, Davis SJ, Creutzig F, Fuss S, Minx J, Gabrielle B, et al. Biophysical and economic limits to negative CO2 emissions. Nat Clim Change. 2016; 6: 42–50. https://doi.org/10.1038/nclimate2870 PLOS ONE Offsetting future agricultural emissions with CO2 removal PLOS ONE | https://doi.org/10.1371/journal.pone.0247887 March 17, 2021 19 / 19