Human and natural resource exposure to extreme drought at 1.0 °C–4.0 °C warming levels

Abstract

Extreme drought occurs on every continent, negatively impacting natural systems and the built environment. Realized and anticipated future warming affects global hydrology, influencing the severity and frequency of both extreme precipitation events and precipitation deficits. Understanding future drought conditions is essential for risk aware water management strategies and to protect food security for a growing human population, while safeguarding natural capital critical to limiting further warming. Here we quantify socioeconomic and ecological exposure to extreme drought. We focus on global, regional, and national scales at increasing levels of climate warming, from today’s 1.0 °C world to 4.0 °C of warming. Drought is quantified using the self-calibrated Palmer drought severity index calculated from globally mosaiced regional climate simulation (REMO2015). Exposure to extreme drought increases monotonically with warming level. For every 0.5 °C warming increase up to 3.0 °C, an additional 619 million people live in areas with 25% likelihood of annual extreme drought, in addition to the 1.7 billion people (25% of 2020 global population) exposed in today’s 1.0 °C world. Spatially, global drying is amplified in the tropics, where drought frequency increases at twice the global rate. Per 0.5 °C increase in warming, extreme drought annual likelihoods increase 1.5 times greater in forested than non-forested areas, jeopardizing climate regulation associated with forested biomes. Cropland exposure to 50% likelihood of annual extreme drought in two of the highest producing countries, China and Brazil, increases 4× and 13× between 1.0 °C and 2.0 °C, spanning a third of national cropland by 3.0 °C. At 1.5 °C (4.0 °C), 16% (39%) of global hydroelectric generating capacity will be exposed to at least a 50% likelihood of annual extreme drought, up from 5% in today’s 1.0 °C world. Given the near-term likelihood of surpassing 1.5 °C, high resolution drought exposure assessments must inform risk aware development and resilience efforts.

Evaluation of CMIP6 Models and Multi-Model Ensemble for Extreme Precipitation over Arid Central Asia

“…The frequency, intensity and duration of extreme climate events (e.g., extreme precipitation, drought, hurricanes, etc.) triggered by global warming have significantly increased, with significant impacts on society and ecosystems [3][4][5][6]. Therefore, it is an important reference value and of practical significance to evaluate the simulation ability of extreme precipitation for the scientific projection of future climate change and the formulation of disaster prevention and mitigation policies.…”

Will the world experience more fractal droughts?

“…In order to create more resilient and adaptive societies in the face of anthropogenic climate change, there is a vital need to understand the impact that climate change might have upon global precipitation patterns. In particular, the intensification of drought events could lead to irreversible damage, especially in view of the sharp increases in global mean surface temperature (Runde et al, 2022). The capacity of the hydroelectric sector to generate electricity would be jeopardized due to the greater likelihood of extreme annual droughts, which would partially hinder decarbonization processes (Runde et al, 2022).…”

“…In particular, the intensification of drought events could lead to irreversible damage, especially in view of the sharp increases in global mean surface temperature (Runde et al, 2022). The capacity of the hydroelectric sector to generate electricity would be jeopardized due to the greater likelihood of extreme annual droughts, which would partially hinder decarbonization processes (Runde et al, 2022). The agricultural sector would be severely compromised as farmland felt the pressure of hydric stress (Rattis et al, 2021), and adaptations in management practices were needed to avoid severe yield losses (Franke et al, 2021).…”

“…Droughts and food insecurity are closely related (Kogan et al, 2019). As a result, the economic development of societies depending upon this sector would suffer a major setback, impoverishing the population and potentially leading to a major exodus from the region affected (Zaveri et al, 2021;Runde et al, 2022). It should be noted that not only countries economically dependent on agriculture would suffer heavy economic losses due to more frequent droughts, but also nations with more advanced economies, such as Europe (Naumann et al, 2021).…”

“…It should be noted that not only countries economically dependent on agriculture would suffer heavy economic losses due to more frequent droughts, but also nations with more advanced economies, such as Europe (Naumann et al, 2021). Tropical forests, the planet's major carbon sinks, would also become sever ely degraded, with greater risk of forest fires; this would hinder the capacity of woodlands to act as carbon sinks (Allen et al, 2010;Runde et al, 2022). Recent studies have found evidence of a possible drought-deforestation feedback in the Amazon rainforest; this, together with the loss of resilience, the longer dry seasons and more frequent droughts, may well have pushed the Amazon towards an irreversible tipping point (Staal et al, 2020;Boulton et al, 2022).…”