Heatwave Trends and the Population Exposure Over China in the 21st Century as Well as Under 1.5 °C and 2.0 °C Global Warmer Future Scenarios

Abstract

Heatwaves exert negative socio-economic impacts and particularly have serious effects on public health. Based on the multi-model ensemble (MME) results of 10 downscaled high-resolution Fifth Phase of the Coupled Model Intercomparison Project (CMIP5) model output from NASA Earth Exchange Global Daily Downscaled Projections (NASA-GDDP), the intensity (largest lasting time), frequency and total duration of heatwaves over China as well as population exposure in the 21st century and at 1.5 °C and 2.0 °C above pre-industrial levels are investigated by using the three indices, the Heat Wave Duration Index (HWDI), annual total frequency of heatwaves (N_HW) and annual total days of heatwaves (T_HW) under RCP4.5 and RCP8.5. The MME results illustrate that heatwaves are projected to become more frequent (0.40/decade and 1.26/decade for N_HW), longer-lasting (3.78 days/decade and 14.59 days/decade for T_HW) as well as more extreme (1.07 days/decade and 2.90 days/decade for HWDI under RCP4.5 and RCP8.5 respectively) over China. High latitude and high altitude regions, e.g., the Tibetan Plateau and northern China, are projected to experience a larger increase of intensity, frequency and the total time of heatwaves compared with southern China (except Central China). The total population affected by heatwaves is projected to increase significantly and will reach 1.18 billion in later part of the 21st century, and there will be more and more people expected to suffer long heatwave time (T_HW) in the 21st century. Compared with a 2.0 °C global warming climate, holding the global warming below 1.5 °C can avoid 26.9% and 29.1% of the increase of HWDI, 34.7% and 39.64% for N_TW and 35.3%–40.10% of T_HW under RCP4.5 and RCP8.5 respectively. The half-degree less of warming will not only decrease the population exposure by 53–83 million but also avoid the threat caused by longer heatwave exposure under the two scenarios. Based on the comprehensive assessment of heatwave under the two RCP scenarios, this work would help to enhance the understanding of climate change and consequent risk in China and thus could provide useful information for making climate adaptation policies.

Future Risks of Unprecedented Compound Heat Waves Over Three Vast Urban Agglomerations in China

“…Given the perceived seriousness of the impact of record-breaking heat waves on human society and natural ecosystems, it is especially important to project the future probability of occurrence of historically unprecedented heat waves. In China, increasing efforts have been devoted to the projections of future changes in different aspects of heat waves, for example, frequency, duration, and intensity (Guo et al, 2017;Sun et al, 2018;Wang et al, 2015Wang et al, , 2019, as well as to the associated population exposure (Huang et al, 2018;Li et al, 2019). However, few studies have focused on the future occurrences of severe heat waves with magnitude greater than historical record-breaking heat events witnessed by densely populated urban areas, primarily because of the lack of appropriate high-resolution observations and climate model projections.…”

Assessing spatiotemporal variation of heat waves during 1961–2016 across mainland China

“…It is widely known that extreme temperature events bring multi-scale, multi-dimensional, and multi-layer threats to socioeconomic development, and recently HWs are occurring frequently across the world (Dosio et al, 2018;Li et al, 2019). A long enough duration of HWs may lead to soil dryness with negative effects on crop growth, have great impacts on livestock and people's health, and bring crises etc.…”

A Stepwise-Clustered Simulation Approach for Projecting Future Heat Wave Over Guangdong Province

“…Daily gridded data from the four GCMs, i.e., Centre National de Recherches Météorologique CNRM-CM5 Model 5 (i.e., CNRM-CM5), Commonwealth Scientific and Industrial Research Organisation Mark 3.6.0 (i.e., CSIRO-Mk3.6.0), Institut Pierre Simon Laplace Model CM5A-MR (i.e., IPSL-CM5A-MR), and Model for Interdisciplinary Research on Climate Version Five (i.e., MIROC5) were downloaded from the CMIP5 dataset to analyze the future variations of heat waves in Guangdong (Li et al, 2019;Xu and Wang, 2019;Ren et al, 2021b). The four GCMs cover the historical and future simulations data under different emission scenarios.…”

“…Previously, there have been some studies investigating the projection of future heat waves in China (Zhou B. T. et al, 2014;Li et al, 2019;Guo et al, 2020). Based on the outputs of 24 GCMs from the coupled model intercomparison projected phase 5 (CMIP5) models under two RCPs, projected changes of temperature extremes in China have been analyzed by Zhou B. T. et al (2014).…”

“…Based on 12 GCMs, Guo et al (2017) projected future heat waves in China and showed that the frequency and intensity of heat waves would have a more dramatic increase under more emission-intense scenarios. Li et al (2019) projected the properties of the future heat waves over China on the basis of the multi-model ensemble of 10 CMIP5 models and illustrated that heat waves are likely to become more frequent (0.40 and 1.26 per decade) and more extreme (1.07 and 2.90 days per decade) under RCP4.5 and RCP8.5, respectively. In brief, the projected variations in heat waves are becoming more obvious.…”