Attributing Country-Level Warming to Individual Major Emitters

Abstract:

Historic and future human influence on the climate system is most commonly assessed by quantifying the impact of total global anthropogenic greenhouse gas emissions. Here, we move beyond assessing total anthropogenic influence towards directly attributing country-level warming to emissions of individual major emitters. For this purpose, we combine output from a global mean temperature emulator (MAGICC, Meinshausen et al., 2011) with a spatially-resolved local temperature emulator (MESMER, Beusch et al., 2020) to obtain large ensembles of several thousand CMIP5-consistent temperature field time series. These emulated Earth system model ensembles approximate large multi-model initial-condition ensembles for given emission scenarios at a negligible computational cost and thus allow to efficiently investigate regional climate change under various emission scenarios. Here, we focus on the role of the five largest historic emitters – China, United States of America, European Union, India, and Russia – for past and near-term future climate change, accounting for pledged emission reductions under the Paris Agreement (1991 – 2030). We quantify the contribution of the top five emitters to country-level climate change both in terms of mean warming and temperature extremes. The top five emitters are shown to have a considerable impact on country-level climate change with different “hotspot” regions emerging, particularly in the northern high latitudes for mean warming and in tropical Africa for the extremes. We additionally provide a complementary climate liability perspective by computing self-inflicted, country-level warming in a counterfactual exercise in which the whole globe follows per capita emissions of selected countries. Our results highlight the importance of individual major emitters in driving regional climate change and the resulting self- and remotely inflicted harm.

Beusch, L., Gudmundsson, L., and Seneviratne, S. I. (ESD, 2020): https://doi.org/10.5194/esd-11-139-2020

Meinshausen, M., Raper, S. C. B., and Wigley, T. M. L. (ACP, 2011): https://doi.org/10.5194/acp-11-1417-2011