Countries most exposed to individual and concurrent extremes and near-permanent extreme conditions at different global warming levels
<p>It is now certain that human-induced climate change is increasing the incidence of extreme temperature, precipitation and drought events globally. A critical aspect of these extremes is their potential concurrency that can result in substantial impacts on society and environmental systems....
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2023-04-01
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Series: | Earth System Dynamics |
Online Access: | https://esd.copernicus.org/articles/14/485/2023/esd-14-485-2023.pdf |
Summary: | <p>It is now certain that human-induced climate change is
increasing the incidence of extreme temperature, precipitation and drought
events globally. A critical aspect of these extremes is their potential
concurrency that can result in substantial impacts on society and
environmental systems. Therefore, quantifying concurrent extremes in current
and projected climate is necessary to take measures and adapt to future
challenges associated with such conditions. Here we investigate changes in
individual and concurrent extremes in multi-model simulations of the sixth
phase of the Coupled Model Intercomparison Project (CMIP6) for different
global warming levels (GWLs). We focus on the individual and simultaneous
occurrence of the extreme events, encompassing heatwaves, droughts, maximum
1 d precipitation (Rx1day), and extreme wind (wind), as well as the compound
events heatwave–drought and Rx1day–wind in the pre-industrial period
(1850–1900; reference period), for approximately present conditions
(<span class="inline-formula">+1</span> <span class="inline-formula"><sup>∘</sup></span>C of global warming), and at three higher global warming
levels (GWLs of <span class="inline-formula">+</span>1.5, <span class="inline-formula">+</span>2 and <span class="inline-formula">+</span>3 <span class="inline-formula"><sup>∘</sup></span>C). We focus our analysis on 139 countries and three climatic macro-regions:
northern mid- and high-latitude countries (MHC), subtropical countries
(STC), and tropical countries (TRC). We find that, on a global scale, most
individual extremes become more frequent and affect more land area for
higher GWLs. Changes in frequency of individual heatwaves, droughts, Rx1day and extreme wind with higher GWLs cause shifts in timing and disproportionate
increases in frequency of concurrent events across different months and
different regions. As a result, concurrent occurrences of the investigated
extremes become 2.0 to 9.6 times more frequent at <span class="inline-formula">+</span>3 <span class="inline-formula"><sup>∘</sup></span>C of
global warming compared to the pre-industrial period. At <span class="inline-formula">+</span>3 <span class="inline-formula"><sup>∘</sup></span>C
the most dramatic increase is identified for concurrent heatwave–drought
events, with a 9.6-times increase for MHC, an 8.4-times increase for STC
and a 6.8-times increase for TRC compared to the pre-industrial period. By
contrast, Rx1day–wind events increased the most in TRC (5.3 times), followed
by STC (2.3 times) and MHC (2.0 times) at <span class="inline-formula">+</span>3 <span class="inline-formula"><sup>∘</sup></span>C with respect to
the pre-industrial period. Based on the 2015 population, these frequency
changes imply an increase in the number of concurrent heatwave–drought
(Rx1day–wind) events per capita for 82 % (41 %) of countries. Our
results also suggest that there are almost no time periods (on average 0
or only 1 month per year) without heatwaves, droughts, Rx1day and extreme
wind for 21 countries at <span class="inline-formula">+</span>1.5 <span class="inline-formula"><sup>∘</sup></span>C of global warming, 37 countries
at <span class="inline-formula">+</span>2 <span class="inline-formula"><sup>∘</sup></span>C and 85 countries at <span class="inline-formula">+</span>3 <span class="inline-formula"><sup>∘</sup></span>C, compared to 2
countries at <span class="inline-formula">+1</span> <span class="inline-formula"><sup>∘</sup></span>C of global warming. This shows that a large
number of countries will shift to near-permanent extreme conditions even at
global warming levels consistent with the limits of the Paris Agreement.
Given the projected disproportionate frequency increases and decreasing
non-event months across GWLs, our results strongly emphasize the risks of
uncurbed greenhouse gas emissions.</p> |
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ISSN: | 2190-4979 2190-4987 |