According to a newly-published NOAA-led study in Geophysical Research Letters, as the globe warms from rising atmospheric concentrations of greenhouse gases, more moisture in a warmer atmosphere will make the most extreme precipitation events even more intense.
The study, conducted by a team of researchers from the North Carolina State University’s Cooperative Institute for Climate and Satellites-North Carolina (CICS-NC) along with NOAA’s National Climatic Data Center (NCDC) and some other agencies report that the extra moisture due to a warmer atmosphere dominates all other factors and leads to notable increases in the most intense precipitation rates.
Besides this, forecasts also show that over the next hundred years, areas that receive lots of precipitation right now are only going to get wetter, and dry areas will go drier for longer periods without seeing a drop. The study also shows a 20% to 30% increase is expected in the maximum precipitation possible over large portions of the Northern Hemisphere by the end of the 21st century, if greenhouse gases continue to rise at a high emissions rate.
Specifically, the new study found that although the 14 climate models differ when it comes to the amount of rainfall in individual locations such as cities, over larger areas, they all point to the same average picture. That is, for every single degree Celsius or Fahrenheit that the global average temperature climbs, heavy rainfall will increase in wet areas by 3.9 percent, while dry areas will experience a 2.6 percent increase in time periods without any rainfall.
The study looked at three factors that go into the maximum precipitation value possible in any given location: moisture in the atmosphere, upward motion of air in the atmosphere, and horizontal winds. The team examined climate model data to understand how a continued course of high greenhouse gas emissions would influence the potential maximum precipitation.
"We looked at rainfall of different types and saw that the extreme heavy rain and the prolonged droughts could both increase drastically," explains William Lau, NASA's deputy director of atmospheric studies and the lead author of the study.
“Our next challenge is to translate this research into local and regional new design values that can be used for identifying risks and mitigating potential disasters. Findings of this study, and others like it, could lead to new information for engineers and developers that will save lives and major infrastructure investments,” said Thomas R. Karl, L.H.D., director of NOAA’s NCDC in Asheville, N.C., and co-author on the paper.
Mahesh Palawat, Head of the weather forecasting team at Skymet Weather says, “One indirect reason for heavy, torrential rain could also be the increased number of high intensity storms and cyclones like Nilam and Sandy which are also a result of the globe warming gradually.” “These studies are therefore not enough, a lot needs to be done to help people in protecting the global environment and staying weather wise.”
