Med countries to get hotter days by the end of ...
Jun 21, 2007 by Michael Redbourn
Research carried out by Noah Diffenbaugh and colleagues at Purdue University, U.S. indicates that countries around the Mediterranean will experience up to five times as many dangerously hot summer days by the end of the century as they do now if greenhouse gas emissions continue their unrelenting escalation.
The model calculated not just an overall increase in temperature but also an increase in the number of extremely hot days.
Noah Diffenbaugh and his colleagues used a climate model for the Mediterranean region which was so precise that they were able to resolve regional changes in temperature for every 20 square kilometres and they concluded that France will undergo the greatest increase in extreme summer temperatures and in some French regions, summer days will be 8°C hotter than they were between 1961 and 1989.
They forecast that the entire thin strip of coast along the Mediterranean which includes the coastlines of Spain, Egypt and Libya will see the largest increase in the number of dangerously hot days, possibly up to 40 more days per year.
The researchers compared two different but possible futures with their model.
In the first, rapid population growth and very few "green" policy measures would mean that greenhouse gas emissions would continue to rise exponentially during the 21st century. The second one assumed that the global population did not rise as fast and that governments and societies adopted more environmentally friendly lifestyles like using greener fuels.
The results from the first harsher scenario showed that the number of dangerously hot days could increase by between 200% and 500% by the end of the century if greenhouse gas emissions continued their exponential rise and as a result the temperatures currently experienced during the hottest two weeks of the summer would become those that will occur during the coldest two weeks of the summer.
Diffenbaugh said, "One might expect that an average warming of four degrees would equate to each day warming by 4 degrees but in fact the hottest days warm quite a bit more. We find that decreases in greenhouse gas emissions greatly reduce the impact but we see negative effects even with reduced emissions”.
He said that “what makes the Mediterranean region so sensitive to climate change is a surface moisture feedback which means that as temperatures rise the landmass not only gets hotter, it gets drier too and this means there is less evaporative cooling”.
Although the results from the second scenario suggested that reducing emissions levels could cut the increase in temperatures by half the researchers said that governments should brace themselves for summer heat waves similar to those that struck Europe in 2003 as they could become commonplace even if climate friendly policies are adopted.
The 2003 heat wave is thought to have been responsible for the deaths of 35,000 people across Europe with nearly15,000 of those occurring in France.