Projected Changes in Climate Extremes Using CMIP6 Simulations Over SREX Regions

Mansour Almazroui,Muhammad Adnan Abid,Sajjad Saeed,Shahzad Kamil,Irfan Ur Rashid,Muhammad Ismail,M Nazrul Islam,Muhammad Azhar Ehsan,Imran Nadeem,Enda O’Brien,Fahad Saeed

doi:10.1007/s41748-021-00250-5

Abstract

This paper presents projected changes in extreme temperature and precipitation events by using Coupled Model Intercomparison Project phase 6 (CMIP6) data for mid-century (2036–2065) and end-century (2070–2099) periods with respect to the reference period (1985–2014). Four indices namely, Annual maximum of maximum temperature (TXx), Extreme heat wave days frequency (HWFI), Annual maximum consecutive 5-day precipitation (RX5day), and Consecutive Dry Days (CDD) were investigated under four socioeconomic scenarios (SSP1-2.6; SSP2-4.5; SSP3-7.0; SSP5-8.5) over the entire globe and its 26 Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate ChangeAdaptation (SREX) regions. The projections show an increase in intensity and frequency of hot temperature and precipitation extremes over land. The intensity of the hottest days (as measured by TXx) is projected to increase more in extratropical regions than in the tropics, while the frequency of extremely hot days (as measured by HWFI) is projected to increase more in the tropics. Drought frequency (as measured by CDD) is projected to increase more over Brazil, the Mediterranean, South Africa, and Australia. Meanwhile, the Asian monsoon regions (i.e., South Asia, East Asia, and Southeast Asia) become more prone to extreme flash flooding events later in the twenty-first century as shown by the higher RX5day index projections. The projected changes in extremes reveal large spatial variability within each SREX region. The spatial variability of the studied extreme events increases with increasing greenhouse gas concentration (GHG) and is higher at the end of the twenty-first century. The projected change in the extremes and the pattern of their spatial variability is minimum under the low-emission scenario SSP1-2.6. Our results indicate that an increased concentration of GHG leads to substantial increases in the extremes and their intensities. Hence, limiting CO2 emissions could substantially limit the risks associated with increases in extreme events in the twenty-first century.

Highlights

Over the last 50 years (1970–2019), precipitation related extremes have resulted in many casualties, and caused enormous socioeconomic damage
The present study aims to evaluate the projected changes in multiple temperature and precipitation extreme indices based on an model ensemble (MME) from 21 Global Climate Models (GCMs) that participated in Phase 6 of Coupled Model Intercomparison Project (CMIP) over 26 sub-regions, including the entire global landmass over the SREX regions
Note that the Coupled Model Intercomparison Project phase 6 (CMIP6) multimodel extreme TXx index is closer to the observations than is the CMIP5 index over most of the globe (Chen et al 2020; Kim et al 2020)

Summary

Introduction

Over the last 50 years (1970–2019), precipitation related extremes have resulted in many casualties, and caused enormous socioeconomic damage. In the last 20 years, the globe has experienced many extreme events including heatwaves (e.g., Europe 2003; Russia 2010), floods (e.g., USA 2011; India 2015), fires (e.g., Australia 2019, 2020), flash flooding in the Arabian deserts (e.g., Saudi Arabia 2009, 2011), and coastal flooding (e.g., Venice 2019, Mumbai 2021, Karachi 2020), which caused catastrophic situations in these regions (e.g., Almazroui et al 2016,2018; Philips 2020; Zhang et al 2020; Herring et al 2019) Are these events a prelude to what is in store in a warmer world, where more intense and more frequent extremes occur as part of the changing climate? As climate extremes impact on human and natural systems in different parts of the globe, in recent times, one of the most important tasks is to understand how climate extremes might behave in future periods under different emission scenarios, both globally and for the SREX regions, using CMIP6 multi-model datasets

Data and Methodology

21 UKESM1-0-LL UK

Projected Changes in Temperature Indices

Projected Changes in Precipitation Indices

Summary and Conclusions

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