Chapter 3 - Changes in climate extremes in observations and climate model simulations. From the past to the future

Abstract

Extreme climate events such as heat waves, heavy precipitation or drought can have devastating impacts on ecosystems and societies. This chapter reviews the available data for studies of, and knowledge about, global changes in a range of different climate extremes including hot and cold temperature extremes, wet and dry precipitation extremes, and high wind speeds. Observations and climate model simulations of the past century agree in showing increases in the intensity and frequency of hot extremes and decreases in the intensity and frequency of cold extremes in most regions globally. Heavy precipitation extremes have been increasing in more regions than they were decreasing, whereas meteorological drought changes depend on the region, season, and the drought indices and datasets used. Climate model projections indicate that these past tendencies are expected to continue and would even accelerate into the future in case of unabated increases in atmospheric greenhouse gas concentrations. This summary suggests that more severe impacts from hot temperature and heavy precipitation extremes can be expected in the future if no suitable adaptation and mitigation measures are taken, while stress from cold extremes is expected to become less relevant.