Drylands climate response to transient and stabilized 2 °C and 1.5 °C global warming targets

Abstract

Drylands are one of the most sensitive areas to climate change. Many previous studies assessed the impact of 1.5 °C and 2 °C warming targets using transient warming scenarios by representative concentration pathways of CMIP5. Here we compared the climate changes over global drylands in transient and stabilized 1.5 °C and 2 °C warmer worlds using Community Earth System Model simulations. The projections indicate a warming of 2.3 °C (1.6 °C) over drylands could occur in a stabilized 2 °C (1.5 °C) warmer world by the end of this century. The warming in drier regions is higher and the hyper-arid areas would experience warming of 2.4 °C (1.8 °C). Comparing the 2 °C to 1.5 °C warming targets, the additional 0.5 °C warming will lead to ~ 1.0 °C warming in drylands of Eurasia and North America. Responding to the 2 °C warming, the increased precipitation (21.8–42.6 mm/year) is not enough to offset the increased PET (88.3–101.7 mm/year) over drylands, resulting in the drylands expansion, and the additional 0.5 °C global warming will aggravate the drought in drylands in southern North America and North Africa. Compared to the stabilized 2 °C warming target, controlling the global warming to within 1.5 °C will reduce the warming in drylands by 0.7 °C, and reduce the drylands expansion relative to 1961–1990 by ~ 44%. Compared to the stabilized warming scenarios, the temperature response and drylands area coverage increase are higher in the transient warming scenarios, but the difference of temperature caused by additional 0.5 °C global warming and the precipitation increase in drylands are lower.