Warnsignal Klima: GESUNDHEITSRISIKEN – GEFAHREN FÜR PFLANZEN, TIERE & MENSCHEN
Kap.1 Der Klimawandel und die bioklimatischen Wirkungskomplexe
Christoph Schär & Erich M. Fischer, Institute for Atmospheric and Climate Science, ETH, Zurich, Switzerland
Summary: Climate change and heat waves – The extreme European summer 2003 has demonstrated how dramatically heat waves can affect even today’s modern civilization. Temperature observations from the past 100 years demonstrate that the frequency, intensity and duration of summer heat waves have strongly increased. Climate change scenarios using global and regional climate models suggest that this increase will accelerate in the future. Detailed analysis of the scenario simulations also shows that summer heat waves are closely tied to the water cycle. Warm European summers are usually dry and often preceded by spring precipitation deficits. In addition to a mere shift towards warmer temperatures, scenario simulations exhibit a complex behavior that includes a pronounced increases in interannual and daily variability, as well as increases in precipitation intensity that occur despite pronounced decreases in summer mean precipitation. It is likely that climate change will most strongly be felt during the summer season, as the projected summer climate is distinct from past experience.