Abstract:
Investigating the impact of high temperature and drought on extreme vegetation productivity losses is crucial for a better understanding ecosystem extremes, facilitating better adaptation to climate change and mitigating their impacts on agricultural production and socio-economic systems. Based on five sets of Gross Primary Productivity (GPP) datasets, we study the contribution of high temperature and drought to extreme GPP losses in China from 1982 to 2016, from the perspective of climatology and long-term trends. In terms of climatology, the extreme GPP losses area-averaged in China is -15.7 gC m-2 yr-1. The frequency and contributions of high temperature and drought are comparable, with drought, high temperature, and combined high-temperature and drought events contributing 45%, 41%, and 23%, respectively, to the total GPP losses. As for the long-term trends from 1982 to 2016, more than 55% of areas in China has experienced an increase in extreme GPP losses, with a regional mean of -2.46 gC m-2 35 yr-1. The increasing frequency of high-temperature, drought, and combined high-temperature and drought events all contribute to this trend significantly, with drought frequency making the largest contribution (-2.47 gC m-2 35yr-1), leading to an increasing trend in over half (61%) of the regions in China. From the perspective of regional distribution, the northern and central China experienced the most significant and pronounced increases in extreme GPP loss from 1982 to 2016. These areas are the hotspots affected by high-temperature and drought. This study quantifies the contribution of the variation in the frequency of high-temperature and drought events in China over the past few decades to extreme GPP loss. It identified the hotspots of terrestrial ecosystems in China where are greatly affected by increasing frequency of high-temperature and drought, thus providing scientific support for a better adaptation and migration to climate change, and sustainable socioeconomic development.