Disasters such as floods, storms, heatwaves and droughts can have enormous implications for health, the environment and economic development. In this article, we address the question how climate change might have influenced the impact of weather-related disasters.
This relation is not straightforward, since disaster burden is not influenced by weather and climate events alone. Other drivers are growth in population and wealth, and changes in vulnerability. We normalized disaster impacts, analyzed trends in these data and compared them with trends in extreme weather and climate events and vulnerability. We followed a 3 by 4 by 3 set-up: three disaster burden categories, four regions and three extreme weather event categories. The trends in normalized disaster impacts show large differences between regions and weather event categories.
Despite these variations, our overall conclusion is that the increasing exposure of people and economic assets has been the major cause of increasing trends in disaster impacts. This holds for long-term trends in economic losses and the number of people affected. We found similar, though more qualitative, results for the number of people killed. However, a role for climate change cannot be excluded. Furthermore, we found that trends in historic vulnerability tend to be stable over time, despite adaptation measures taken by countries.
Based on these findings, we derived disaster impact projections for the coming decades. We argue that projections beyond 2030 are too uncertain, not only due to unknown changes in vulnerability, but also due to increasing non-stationarities in normalization relations.