Extreme hydro-meteorological events and their impacts.From the global down to the regional scale

Abstract

Despite the progress in technology, the risk of weather-related disasters has not been eradicated and never will be. On the global scale, disasters are becoming both more frequent and more destructive, annually causing material losses worth tens of billions of Euros, as well as several thousand fatalities. Furthermore, catastrophic weather events have been the subject of a rapid upward trend, with the value of material damage increasing by an order of magnitude over the last four decades, in inflation-adjusted monetary units. There is now an increasing body of evidence of ongoing planetary climate change (global warming), which has brought about considerable changes where extreme hydro-meteorological events are concerned, and is likely to lead to even more marked changes in the future. Typically, changes in extremes are more pronounced and exert more impact than changes in mean values. Among the extremes on the rise are the number of hot days and tropical nights; the duration and intensity of heatwaves; precipitation intensity (and resulting floods, landslides and mudflows); the frequency, length and severity of droughts; glacier and snow melt; tropical cyclone intensity and sea level and storm surges. In turn, a ubiquitous decrease in cold extremes (number of cool days and nights, and frost days) is projected. Increases in climate extremes associated with climate change are likely to cause physical damage and population displacement, as well as having adverse effects on food production and the availability and quality of fresh water. A discussion of hydro-meteorological extremes and their impacts is therefore provided here in relation to a range of scales, and with the context for adaptation and mitigation also being alluded to.