A worldwide review of global rainfall data led by the University of Adelaide has found that the intensity of the most extreme rainfall events is increasing across the globe as temperatures rise.
In the most comprehensive review of changes to extreme rainfall ever undertaken, researchers evaluated the association between extreme rainfall and atmospheric temperatures at more than 8000 weather gauging stations around the world.
Lead author Dr Seth Westra said, "The results are that rainfall extremes are increasing on average globally. They show that there is a 7% increase in extreme rainfall intensity for every degree increase in global atmospheric temperature.
"Assuming an increase in global average temperature by 3 to 5 degrees Celsius by the end of the 21st century, this could mean very substantial increases in rainfall intensity as a result of climate change."
- From The University of Adelaide media centre. Read the full media release here (28)
This work is being published in the Journal of Climate and can be seen online, here, but is not open access.
A related blog entry by Seth Westra in The HydroFiles begins here:
Changes to the temporal distribution of Australian rainfall
January 20, 2013
"The question of how rainfall intensity will change with global warming is an important one, and confidence is building within the scientific community that rainfall extremes will on average become more intense and/or more frequent as global temperatures increase. While this may be true on average, however, what is perhaps less well appreciated is that there are different types of weather systems that produce rainfall, and that these might change in different ways and sometimes even in opposing directions as the climate warms. This substantially complicates efforts to provide robust projections of likely changes to rainfall extremes at any specific location, and therefore hampers efforts to adapt to future flood risk.
At the largest scale, global atmospheric circulation patterns such as the Hadley cell, which are responsible for transporting huge volumes of moisture over large distances, play the leading role in determining the global distribution of rainfall. An increasing number of scientists are finding that these circulation patterns are changing (34), with the consequence that the distribution of global precipitation might also change. This means that while on balance the total global volume of rainfall is expected to increase with climate change, changing circulation patterns will cause certain regions, and particularly the arid and semi-arid zones which are already relatively dry, to become drier still."
Read the full blog post >
Photo Credit: Dr. RawheaD via Compfight cc