Climate change hotspots in the CMIP5 global climate model ensemble

Filippo Giorgi,Noah S Diffenbaugh

doi:10.1007/s10584-012-0570-x

Abstract

We use a statistical metric of multi-dimensional climate change to quantify the emergence of global climate change hotspots in the CMIP5 climate model ensemble. Our hotspot metric extends previous work through the inclusion of extreme seasonal temperature and precipitation, which exert critical influence on climate change impacts. The results identify areas of the Amazon, the Sahel and tropical West Africa, Indonesia, and the Tibetan Plateau as persistent regional climate change hotspots throughout the 21st century of the RCP8.5 and RCP4.5 forcing pathways. In addition, areas of southern Africa, the Mediterranean, the Arctic, and Central America/western North America also emerge as prominent regional climate change hotspots in response to intermediate and high levels of forcing. Comparisons of different periods of the two forcing pathways suggest that the pattern of aggregate change is fairly robust to the level of global warming below approximately 2 °C of global warming (relative to the late-20th-century baseline), but not at the higher levels of global warming that occur in the late-21st-century period of the RCP8.5 pathway, with areas of southern Africa, the Mediterranean, and the Arctic exhibiting particular intensification of relative aggregate climate change in response to high levels of forcing. Although specific impacts will clearly be shaped by the interaction of climate change with human and biological vulnerabilities, our identification of climate change hotspots can help to inform mitigation and adaptation decisions by quantifying the rate, magnitude and causes of the aggregate climate response in different parts of the world.Electronic supplementary materialThe online version of this article (doi:10.1007/s10584-012-0570-x) contains supplementary material, which is available to authorized users.

Highlights

It is established that human activities have been the primary cause of observed global warming (IPCC 2007), and that the climate system is already committed toF
Comparisons of different periods of the two forcing pathways suggest that the pattern of aggregate change is fairly robust to the level of global warming below approximately 2 °C of global warming, but not at the higher levels of global warming that occur in the late-21st-century period of the RCP8.5 pathway (Fig. 1)
The pattern of greatest relative aggregate change occurring over tropical regions is seen during the 2046–2065 period of RCP8.5, when median global warming is larger than in the 2080–2099 period of RCP4.5 (Rogelj et al 2012))

Summary

Introduction

It is established that human activities have been the primary cause of observed global warming (IPCC 2007), and that the climate system is already committed toF. Given the availability of a new generation of global climate model simulations that comprise the CMIP5 ensemble (Taylor et al 2012), we quantify the transient emergence of global hotspot patterns using a statistical metric of aggregate multi-dimensional climate change. This metric extends the statistical approach of Diffenbaugh et al (2008) to include measures of extreme seasonal temperature and precipitation, which are important for climate change impacts

Methods

Results

Conclusion