On July 19, 2022, a temperature of 40.2 degrees Celsius was measured in the UK village Coningsby, which turned out to be the highest temperature ever recorded in the country. According to the California Office of Environmental Health Hazard Assessment, the frequency of extreme heat events across California have increased by more than 1.76 degrees Fahrenheit since 1950, leading to multiple wildfires in recent years. In 2022, Hungary experienced the driest seven months since 1901, causing ten of Hungary’s 12 water management directorates to be on water shortage alert.
Extreme heat and drought events are all extreme weather events. According to the US Environmental Protection Agency, past studies have indicated that extreme weather events are likely to increase both in their frequency and intensity as a result of human-induced climate change. Learning about the statistics, we might ask, “How bad could these extreme high temperatures and droughts become in the future?”
According to an Oxford study published in Nature Sustainability in January 2023, the compound consequences of extreme heat and drought events is predicted to affect more than 90% of the world’s population. Using simulations from a large-scale climate-hydrology model, the study projected the frequency of combined droughts with extreme heat waves to experience a tenfold increase globally under the highest emissions scenario. Moreover, through a combination of satellite observations and field measurements and analyses, a negative relationship between temperature and terrestrial water storage was found that was potentially a consequence of their common underlying atmospheric conditions such as energy demand or water vapour deficits. This negative correlation further supports the idea that extreme heat events are likely to occur with droughts.
The study also predicted how individuals might be impacted by combined drought-heatwave events. Ecologically, these combined extreme weather events are projected to considerably affect the productivity of the terrestrial biosphere acting as a means to capture carbon dioxide. After severe droughts and heatwaves, there is usually a decrease in plant growth and recovery, reducing plants’ carbon sequestration capacity.
Combined drought-heatwave events are also predicted to have profound effects on society and people’s well-being. A projected increase in plant mortality and decrease in crop yield will pose challenges to the agricultural industry. Extreme weather might decrease electric grid reliability, negatively affecting many natural and manmade systems and infrastructures. The reduced availability of terrestrial water storage may also lead to changes in global water and energy budgets. Moreover, the study states that based on information from future climate scenario models, over 90% of GDP in most global land areas will be affected by the increasing occurrence of severe heat and drought events by the end of this century, with rural and poor areas experiencing more severe effects.
“The work has wide-reaching implications across the broad fields of sustainability, including climate science, hydrology, ecology, water resources, and risk assessment,” Dr. Jiabo Yin, the corresponding author of the study, stated.
Another main author of the study Professor Louise Slater linked this study to the UN Sustainable Development Goals (SDGs). “Understanding compounding hazards in a warming Earth is essential for the implementation of the SDGs, in particular SDG13 that aims to combat climate change and its impacts,” she said.
