Climate Extremes and Their Implications for Impact and Risk Assessment https://doi.org/10.1016/B978-0-12-814895-2.00001-X 1 Copyright © 2020 Elsevier Inc. All rights reserved. CHAPTER 1 Climate extremes and their implications for impact and risk assessment: A short introduction Jana Sillmann a , Sebastian Sippel b,c a Center for International Climate Research Oslo (CICERO), Oslo, Norway b Norwegian Institute of Bioeconomy Research, Ås, Norway c ETH Zürich, Zürich, Switzerland 1 Introduction Present and future climate extremes imply adverse impacts, and therefore often pose severe societal challenges across a range of sectors, including, for instance, agriculture, terrestrial and marine ecosystems, health, infrastruc- ture, and might even exacerbate or trigger human conflict (IPCC, 2012). About 90% of all disasters are caused by weather-related hazards, such as floods, storms, extreme temperatures, and droughts (UNISDR, 2015). A combination of these hazards, either sequentially such as a tropical cyclone followed by a heatwave (Lin, 2019), or a concurrent compounding of haz- ardous factors such as heat and drought (e.g., Mazdiyasni and AghaKouchak, 2015), can be even more disastrous than a single hazard. Moreover, not only the interdependence between hazards but also interactions between hazards, ecosystem or societal responses, and vulnerabilities can amplify the risk (IPCC, 2012). Extreme event impacts are increasingly recognized, methodologies to ad- dress such impacts and the degree of our understanding and prediction capa- bilities, however, vary widely among different sectors and disciplines. Moreover, traditional climate extreme indices and large-scale multimodel intercompari- sons that are used for future projections of extreme events and associated im- pacts often fall short in capturing the full complexity of impact systems. While at present most scientific studies are studying individual sectors only, an improved exchange between sectors around methodologies in terms of impact and risk assessment will yield a better understanding of mechanisms and processes driving impacts and systemic risk.