Projected increases in magnitude and socioeconomic exposure of global droughts in 1.5 and 2 °C warmer climates
<p>The Paris Agreement sets a long-term temperature goal to hold global warming to well below 2.0 <span class="inline-formula"><sup>∘</sup></span>C and strives to limit it to 1.5 <span class="inline-formula"><sup>∘&l...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-01-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/24/451/2020/hess-24-451-2020.pdf |
| Summary: | <p>The Paris Agreement sets a long-term temperature goal to hold global warming to well below 2.0 <span class="inline-formula"><sup>∘</sup></span>C and strives to limit it to 1.5 <span class="inline-formula"><sup>∘</sup></span>C above preindustrial levels. Droughts with either intense
severity or a long persistence could both lead to substantial impacts such
as infrastructure failure and ecosystem vulnerability, and they are
projected to occur more frequently and trigger intensified socioeconomic
consequences with global warming. However, existing assessments targeting
global droughts under 1.5 and 2.0 <span class="inline-formula"><sup>∘</sup></span>C warming levels usually neglect the multifaceted nature of droughts and might underestimate
potential risks. This study, within a bivariate framework, quantifies the
change in global drought conditions and corresponding socioeconomic
exposures for additional 1.5 and 2.0 <span class="inline-formula"><sup>∘</sup></span>C warming trajectories. The drought characteristics are identified using the Standardized Precipitation Evapotranspiration Index (SPEI) combined with the run theory, with the climate scenarios projected by 13 Coupled Model Inter-comparison Project Phase 5 (CMIP5) global climate models (GCMs) under three representative concentration pathways (RCP 2.6, RCP4.5 and RCP8.5). The copula functions and the most likely realization are incorporated to model the joint distribution of drought severity and duration, and changes in the bivariate return period with global warming are evaluated. Finally, the drought exposures of populations and regional gross domestic product (GDP) under different shared socioeconomic pathways (SSPs) are investigated globally. The results show that within the bivariate framework, the historical 50-year droughts may double across 58 % of global landmasses in a 1.5 <span class="inline-formula"><sup>∘</sup></span>C warmer world, while when the warming climbs up to 2.0 <span class="inline-formula"><sup>∘</sup></span>C, an additional 9 % of world landmasses would be exposed to such catastrophic drought deteriorations. More than 75 (73) countries' populations (GDP) will be completely affected by increasing drought risks under the 1.5 <span class="inline-formula"><sup>∘</sup></span>C warming, while an extra 0.5 <span class="inline-formula"><sup>∘</sup></span>C warming will further lead to an additional 17 countries suffering from a nearly unbearable situation. Our results demonstrate that limiting global warming to 1.5 <span class="inline-formula"><sup>∘</sup></span>C, compared with 2 <span class="inline-formula"><sup>∘</sup></span>C warming, can perceptibly mitigate the drought impacts over major regions of the world.</p> |
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| ISSN: | 1027-5606 1607-7938 |