Washington: A new study has showed that a significant build-up in greenhouse gases in atmosphere can change worldwide precipitation patterns, a widely discussed technological approach to reduce future global warming may also interfere with rainfall and snowfall.
The international study, led by scientists at the National Center for Atmospheric Research (NCAR), finds that global warming caused by a massive increase in greenhouse gases will spur a nearly 7 percent average increase in precipitation compared to preindustrial conditions.
But trying to resolve the problem through "geoengineering" could result in monsoonal rains in North America, East Asia, and other regions dropping by 5-7 percent compared to preindustrial conditions. Globally, average precipitation could decrease by about 4.5 percent.
Lead author NCAR scientist Simone Tilmes, said that geoengineering the planet doesn`t cure the problem and even if one of these techniques could keep global temperatures approximately balanced, precipitation would not return to preindustrial conditions.
Co-author NCAR scientist John Fasullo said that if you don`t like warming, you can reduce the amount of sunlight reaching the surface and cool the climate.
He said that but if that is done, large reductions in rainfall are unavoidable.
The research team turned to 12 of the world`s leading climate models to simulate global precipitation patterns if the atmospheric level of carbon dioxide, a leading greenhouse gas, reached four times the level of the preindustrial era. They then simulated the effect of reduced incoming solar radiation on the global precipitation patterns.
The scientists chose the artificial scenario of a quadrupling of carbon dioxide levels, which is on the high side of projections for the end of this century, in order to clearly draw out the potential impacts of geoengineering.
In line with other research, they found that an increase in carbon dioxide levels would significantly increase global average precipitation, although there would likely be significant regional variations and even prolonged droughts in some areas.
The study has been published online in the Journal of Geophysical Research: Atmospheres.
