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Nature. 2019 Jul 1. doi: 10.1038/s41586-019-1364-3. [Epub ahead of print]

Committed emissions from existing energy infrastructure jeopardize 1.5 °C climate target.

Author information

1
Department of Earth System Science, University of California, Irvine, CA, USA. dtong3@uci.edu.
2
Ministry of Education, Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China. dtong3@uci.edu.
3
Ministry of Education, Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China. qiangzhang@tsinghua.edu.cn.
4
Ministry of Education, Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China.
5
Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA.
6
CoalSwarm, San Francisco, CA, USA.
7
Department of Earth System Science, University of California, Irvine, CA, USA.
8
Department of Earth System Science, University of California, Irvine, CA, USA. sjdavis@uci.edu.
9
Ministry of Education, Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China. sjdavis@uci.edu.

Abstract

Net anthropogenic carbon dioxide (CO2) emissions must approach zero by mid-century (2050) to stabilize global mean temperature at the levels targeted by international efforts1-5. Yet continued expansion of fossil-fuel energy infrastructure implies already 'committed' future CO2 emissions6-13. Here we use detailed datasets of current fossil-fuel-burning energy infrastructure in 2018 to estimate regional and sectoral patterns of 'committed' CO2 emissions, the sensitivity of such emissions to assumed operating lifetimes and schedules, and the economic value of associated infrastructure. We estimate that, if operated as historically, existing infrastructure will emit about 658 gigatonnes (Gt) of CO2 (ranging from 226 to 1,479 Gt CO2 depending on assumed lifetimes and utilization rates). More than half of these emissions are projected to come from the electricity sector, and infrastructure in China, the USA and the EU28 countries represent approximately 41 per cent, 9 per cent and 7 per cent of the total, respectively. If built, proposed power plants (planned, permitted or under construction) would emit approximately an additional 188 (range 37-427) Gt CO2. Committed emissions from existing and proposed energy infrastructure (about 846 Gt CO2) thus represent more than the entire remaining carbon budget if mean warming is to be limited to 1.5 °C with a probability of 50-66 per cent (420-580 Gt CO2)5, and perhaps two-thirds of the remaining carbon budget if mean warming is to be limited to below 2 °C (1,170-1,500 Gt CO2)5. The remaining carbon budget estimates are varied and nuanced14,15, depending on the climate target and the availability of large-scale negative emissions16. Nevertheless, our emission estimates suggest that little or no additional CO2-emitting infrastructure can be commissioned, and that infrastructure retirements that are earlier than historical ones (or retrofits with carbon capture and storage technology) may be necessary, in order to meet the Paris Agreement climate goals17. On the basis of the asset value per ton of committed emissions, we estimate that the most cost-effective premature infrastructure retirements will be in the electricity and industry sectors, if non-emitting alternative technologies are available and affordable4,18.

PMID:
31261374
DOI:
10.1038/s41586-019-1364-3

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