Growing aridity poses threats to global land surface

Abstract

Global warming has impacted water cycle, but not exist a global study of the changes at global scale of the impacts on water available for plants. Here, cloud-optimized monthly aggregated climate reanalysis from the European Centre for Medium-Range Weather Forecasts dataset indicates that from 1960 to 2023, 27.9% of the global land surface became significantly more arid, while 20.5% became significantly less arid. This indicates a shift towards drier climates, with humid, semi-humid, and semi-arid areas decreasing by 8.51, 1.45, and 0.53 million-km², respectively, and arid and hyper-arid areas increasing by 6.34 and 4.18 million-km², respectively. This total increase of 9.99 million km² in arid areas represents 5.9% of the global land surface, excluding Greenland and Antarctica. Accelerated aridification has occurred in already dry regions, such as South-west North-America, North-Brazil, the European-Basin, North-Africa, the Middle-East, the Sahel, and central-Asia, with central-Africa as a new hotspot. The main driver is the disproportionate increase in potential evapotranspiration relative to rainfall, attributed to rising atmospheric temperatures, which also reduces the land’s carbon sink capacity, potentially exacerbating climate warming. From 1960 to 2023, 27.9% of the global land surface became more arid, while 20.5% became less arid, resulting in a 5.9% increase in arid regions, linked to reduction of land’s carbon sink capacity and climate warming, according to analysis of the ERA5-land monthly aggregated climate reanalysis dataset.