Abstract
Temperature targets of the Paris Agreement limit global net cumulative emissions to very tight carbon budgets. The possibility to overshoot the budget and offset near-term excess emissions by net-negative emissions is considered economically attractive as it eases near-term mitigation pressure. While potential side effects of carbon removal deployment are discussed extensively, the additional climate risks and the impacts and damages have attracted less attention. We link six models for an integrative analysis of the climatic, environmental and socio-economic consequences of temporarily overshooting a carbon budget consistent with the 1.5 ◦C temperature target along the cause-effect chain from emissions and carbon removals to climate risks and impact. global climatic indicators such as CO2-concentration and mean temperature closely follow the carbon
budget overshoot with mid-century peaks of 50 ppmv and 0.35 ◦C, respectively. Our findings
highlight that investigating overshoot scenarios requires temporally and spatially differentiated
analysis of climate, environmental and socioeconomic systems. We find persistent and spatially
heterogeneous differences in the distribution of carbon across various pools, ocean heat content,
sea-level rise as well as economic damages. Moreover, we find that key impacts, including
degradation of marine ecosystem, heat wave exposure and economic damages, are more severe in
equatorial areas than in higher latitudes, although absolute temperature changes being stronger in
higher latitudes. The detrimental effects of a 1.5 ◦C warming and the additional effects due to
overshoots are strongest in non-OECD countries (Organization for Economic Cooperation and
Development). Constraining the overshoot inflates CO2 prices, thus shifting carbon removal
towards early afforestation while reducing the total cumulative deployment only slightly, while
mitigation costs increase sharply in developing countries. Thus, scenarios with carbon budget
overshoots can reverse global mean temperature increase but imply more persistent and
geographically heterogeneous impacts. Overall, the decision about overshooting implies more
severe trade-offs between mitigation and impacts in developing countries.
budget overshoot with mid-century peaks of 50 ppmv and 0.35 ◦C, respectively. Our findings
highlight that investigating overshoot scenarios requires temporally and spatially differentiated
analysis of climate, environmental and socioeconomic systems. We find persistent and spatially
heterogeneous differences in the distribution of carbon across various pools, ocean heat content,
sea-level rise as well as economic damages. Moreover, we find that key impacts, including
degradation of marine ecosystem, heat wave exposure and economic damages, are more severe in
equatorial areas than in higher latitudes, although absolute temperature changes being stronger in
higher latitudes. The detrimental effects of a 1.5 ◦C warming and the additional effects due to
overshoots are strongest in non-OECD countries (Organization for Economic Cooperation and
Development). Constraining the overshoot inflates CO2 prices, thus shifting carbon removal
towards early afforestation while reducing the total cumulative deployment only slightly, while
mitigation costs increase sharply in developing countries. Thus, scenarios with carbon budget
overshoots can reverse global mean temperature increase but imply more persistent and
geographically heterogeneous impacts. Overall, the decision about overshooting implies more
severe trade-offs between mitigation and impacts in developing countries.
| Original language | English |
|---|---|
| Article number | 054015 |
| Journal | Environmental Research Letters |
| Volume | 18 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 1 May 2023 |
Bibliographical note
Funding Information:Development of PISM is supported by NSF Grant Nos. PLR-1603799 and PLR-1644277 and NASA Grant No. NNX17AG65G J Garbe, R Winkelmann and M Zeitz were supported by the Leibniz Association (project ‘DominoES’) as well as by the Deutsche Forschungsgemeinschaft (DFG) through Grant No. WI4556/3-1. D P Keller, Dr Jessica Strefler and N Bauer received funding from the German Research Foundation’s Priority Program SPP 1689 ‘Climate Engineering’ (CDR-MIA project KE 2149/2-1). This work was supported by the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 821124 (NAVIGATE). The authors gratefully acknowledge the European Regional Development Fund (ERDF), the German Federal Ministry of Education and Research and the Land Brandenburg for supporting this project by providing resources on the high-performance computer system at the Potsdam Institute for Climate Impact Research.
Publisher Copyright:
© 2023 The Author(s). Published by IOP Publishing Ltd
Copyright:
Copyright 2023 Elsevier B.V., All rights reserved.