Climate Risk Management (Jan 2022)
Changes in global heat waves and its socioeconomic exposure in a warmer future
Abstract
Heat waves are continuous high temperature processes, which are defined as the daily maximum temperature exceeding the absolute-relative combined high temperature thresholds for more than three consecutive days in this study. Because of its unprecedented casualties, devastating compound disasters and irreversible deterioration trends, heat waves have attracted worldwide concern, while its global changes and socioeconomic impacts still need further study. Using three historical reanalysis data and multi scenario CMIP6 modeled data, Global Heat Wave Toolbox (GHWT) was developed to generate heat wave matrix from 1971 to 2100. The long-term changing characteristics of global heat waves were also analyzed. Next, population and GDP projections are employed to estimate future socioeconomic exposure and risks. The results show that except for high latitudes (latitude greater than 60°), high elevations and some coastal areas, heat waves have visited about 45% (±3%) of the global land area (excluding Antarctica). North Africa, North Australia, South Asia, and the Arabian Peninsula are detected as high heat wave area, where experience more than three heat waves with total duration over 15 days annually. Additionally, the average growth rate of global heat waves under SSP2 4.5 and SSP5 8.5 may be 2–3 times and 3–5 times of that under SSP1 2.6, respectively. Under SSP2 4.5, there may be about 7.32 billion people exposed to heat waves in 2100, accounting for 82.65% of the global population. Economic exposure may reach $433.37 trillion in 2100, accounting for 82.23% of the total global economy in that year. India could have the highest population and economic exposure, follow by populous countries, such as Pakistan and Bangladesh, and major economies, such as China and the United States. Under SSP1 2.6, the increase in heat waves may slow down significantly. Moreover, North Africa, Australia, and Brazil are identified as rapid heat wave growth area. Our study highlights the heat wave of future growth and its socioeconomic impacts, as well as the necessity for climate mitigation and adaptation measures.
