A new study says that air pollution or aerosols and greenhouse gases have similar effects on rainfall, though they have different properties.
Human activities have led to an increase in the level of greenhouse gases and pollutants in the atmosphere. Both of these have very different properties from each other. While greenhouses gases easily mix and are distributed evenly across the globe, aerosols vary greatly in local concentration and tend to be found near emission sources such as industrial centers in Asia and North America.
However, in a new study researchers were surprised to find that despite these different characteristics, air pollution or aerosols and greenhouse gases have similar effects on rainfall. According to the researchers of the study, this new discovery makes it hard to tell greenhouse gases apart from aerosols.
Aerosols affect climate by changing the behavior of clouds within days and minutes. It also affects climate in a longer process, which takes years and is mediated by interactions with the ocean and atmosphere.
"Although much of the aerosol research has focused on microphysical processes, over the ocean the climate response to aerosols appears to be insensitive to details of the micro-processes in clouds," lead-author Shang-Ping Xie, a professor of climate science and first Roger Revelle Chair in Environmental Science at Scripps, said in a press release. "The climate changes induced by greenhouse gases and by aerosols share a common set of ocean-atmospheric feedback structures, explaining the spatial resemblance between the two types of response."
"Innovative model experiments are now needed," says coauthor Baoqiang Xiang, postdoctoral fellow at the IPRC. "We want to probe the ocean-atmosphere interaction mechanisms that mediate these rainfall patterns and to determine what forms the foundation. This will allow us to develop more reliable regional climate projections."
