Observationally constrained projection of the reduced intensification of extreme climate events in Central Asia from 0.5\xa0\xb0C less global warming

Dongdong Peng,Tianjun Zhou,Lixia Zhang,Wenxia Zhang,Xiaolong Chen

doi:10.1007/s00382-019-05014-6

Abstract

Arid Central Asia is highly vulnerable to extreme climate events. Information on potential future changes in extreme climate events in Central Asia is limited. In this study, the performances of models from the Coupled Model Intercomparison Project phase 5 (CMIP5) in simulating climatological extremes in Central Asia are first evaluated, and a bias correction method is employed to constrain future projections. The responses of extreme climate events over Central Asia to future warming and, in particular, the impact of 1.5 and 2 °C global warming scenarios are then assessed based on the observationally constrained projections. During the twenty-first century, coldest night (TNn), coldest day (TXn), warmest night (TNx), warmest day (TXx), 1-day maximum precipitation (RX1 day), 5-day maximum precipitation (RX5 day), and precipitation intensity (SDII) in Central Asia would robustly increase at best estimated rates of 1.93 °C, 1.71 °C, 1.18 °C, 1.25 °C, 6.30%, 5.71%, and 4.99% per degree of global warming, respectively, under Representative Concentration Pathway (RCP) 8.5. Compared with the 2 °C warming scenario, limiting global warming to 1.5 °C could reduce the intensification (relative to 1986–2005) of TNn, TNx, TXn, TXx, RX1 day, RX5 day, and SDII by 33%, 24%, 32%, 29%, 39%, 42%, and 53% from the best estimates under RCP8.5, respectively. The avoided intensification of TNn, TNx, TXn and TXx (RX1 day and SDII) would be larger (smaller) under RCP4.5. This suggests that a low warming target is necessary for avoiding the dangerous risk of extremes in this arid region.

Highlights

Human-induced global warming has a great impact on society at both global and regional scales (IPCC 2013)
The spatial distributions of these indices can be well captured by the Coupled Model Intercomparison Project phase 5 (CMIP5) multimodel ensemble mean (MME) (Fig. 1b, e, h, and k)
The meridional distribution and the locations of these two centers of observed consecutive dry days (CDD) are well captured by the CMIP5 MME (Fig. 2b)

Summary

Introduction

Human-induced global warming has a great impact on society at both global and regional scales (IPCC 2013). Central Asia is an arid region with annual precipitation less than 300 mm and is characterized by a fragile ecological environment with sparse vegetation and vast barrenness (Huang et al 2016; Hu et al 2017). Understanding and projecting the potential changes in climate extremes over Central Asia are of great importance to both policymaking and climate change adaption activities. Central Asia has witnessed significant warming during the past half-century at a rate of approximately 0.30 °C decade−1, which is much faster than the global land average rate (0.19 °C decade−1) (Hu et al 2014; IPCC 2013). Associated with significant warming, precipitation in the eastern part of Central Asia has increased significantly in the

Objectives

Results

Conclusion