societal changes such as increase in human population have led to a steep rise in the costs of flood damages in the us . A study conducted by Roger Pielke Jr and Mary Downton of the National Centre for Atmospheric Research ( ncar ), Colorado, usa , states that even without an increase in precipitation (rainfall) total flood damage in the us will continue to rise in the future. us annual flood losses (adjusted for inflation) rose from us $1 billion in the 1940s to us $5 billion in the 1990s. "Climate plays an important role but it is not the sole determinant in the growth of damaging floods in the us in recent decades,' the authors have concluded.

Pielke and Downton along with their colleagues studied the relationship between increasing precipitation, population, national wealth and damages caused due to floods. They discovered that population growth alone accounted for 43 per cent of the rise in flood damages from 1932 to 1997. Increased precipitation levels showed a very minor effect as most of the remaining 57 per cent was due to the burgeoning national wealth.

Climate experts claim that there has been a rise in precipitation in some areas of the country over the past century. The Intergovernmental Panel on Climate Change ( ipcc ) has reported that warmer climate could lead to more torrents. "The findings of our study are consistent with the conclusions of the ipcc ,' says Pielke. But the debate over the science of global warming need not stand in the way of effective actions to better address climate impacts, the authors noted. "We can manage spiralling flood costs without waiting for precise answers from climate change research. In this sense the debate over global warming misses the mark,' he added.