Nice, France. Cities along Mediterranean coastlines could especially suffer from heatwaves in the future. (Credit: iStockphoto)
Heatwaves could especially pose an increased health risk this century in Southern European river valleys and along the Mediterranean coast, a study by two scientists from ETH Zurich has revealed.
During the scorching summer of 2003, thermometers soared to over 40°C in the first two weeks of August; estimates on excess mortality amount to about 40,000 heat-related deaths across Europe; the heatwave caused water shortage and bottlenecks in power supply; the high water temperatures caused fish to die; and Swiss Re estimated the damage caused by reduced crop yields at 13 billion euros.
Key factors: Temperature and atmospheric humidity
The scientists see two reasons as to why the geographic distribution of the future affected areas is consistent in all models: firstly, due to the low altitude these regions experience particularly high temperatures; secondly, the comparatively high absolute humidity amplifies the health impacts during heatwaves. Although the models predict that the increasing aridity of Southern Europe reduces the relative atmospheric humidity somewhat, a certain level of humidity naturally remains precisely in the especially hard-hit regions along the coasts. Then there is also the fact that the diurnal temperature range, the difference between day and night-time temperatures, remains constant, which means the day and night-time temperatures are increasing in parallel; in other regions of Europe, the nights would warm up somewhat less.
Highly populated areas particularly at risk
It's concerning, says Fischer, that most of these high-risk areas are densely populated, with major cities like Milan, Athens or Naples being affected. Cities are warming up more intensely during the day and cooling off less effectively at night than the open land. However, this so-called "heat island effect" and the cities' air pollution wasn't even accounted for in this study -- which means the situation on the ground could get even worse. That said, the two researchers stress that it is possible to adapt to the new conditions up to a certain point by establishing a corresponding infrastructure and certain rules of conduct.
References
Fischer, E.M., C. Schär, 2010: Consistent geographical patterns of changes in high-impact European heatwaves, Nature Geoscience, doi:10.1038/NGEO866.
During the scorching summer of 2003, thermometers soared to over 40°C in the first two weeks of August; estimates on excess mortality amount to about 40,000 heat-related deaths across Europe; the heatwave caused water shortage and bottlenecks in power supply; the high water temperatures caused fish to die; and Swiss Re estimated the damage caused by reduced crop yields at 13 billion euros.
Key factors: Temperature and atmospheric humidity
The scientists see two reasons as to why the geographic distribution of the future affected areas is consistent in all models: firstly, due to the low altitude these regions experience particularly high temperatures; secondly, the comparatively high absolute humidity amplifies the health impacts during heatwaves. Although the models predict that the increasing aridity of Southern Europe reduces the relative atmospheric humidity somewhat, a certain level of humidity naturally remains precisely in the especially hard-hit regions along the coasts. Then there is also the fact that the diurnal temperature range, the difference between day and night-time temperatures, remains constant, which means the day and night-time temperatures are increasing in parallel; in other regions of Europe, the nights would warm up somewhat less.
Highly populated areas particularly at risk
It's concerning, says Fischer, that most of these high-risk areas are densely populated, with major cities like Milan, Athens or Naples being affected. Cities are warming up more intensely during the day and cooling off less effectively at night than the open land. However, this so-called "heat island effect" and the cities' air pollution wasn't even accounted for in this study -- which means the situation on the ground could get even worse. That said, the two researchers stress that it is possible to adapt to the new conditions up to a certain point by establishing a corresponding infrastructure and certain rules of conduct.
References
Fischer, E.M., C. Schär, 2010: Consistent geographical patterns of changes in high-impact European heatwaves, Nature Geoscience, doi:10.1038/NGEO866.
Source: http://www.sciencedaily.com/
