While the U.S. Clean Air Act, passed in 1970, helped to dramatically reduce pollution, scientists have discovered it has also contributed to more extreme weather, which was previously suppressed by chemicals in the air that reflected some of the sun's rays into space.
What's happening?
A recent study published in Nature Communications found that the passage of the Clean Air Act was a double-edged sword. While it helped stave off some of the heavy rain and flooding caused, in part, by our warming planet, it acted much like a dam holding back a river.
As levels of some types of air pollution have gradually dropped over the last 50 years, devastating hurricanes, flash floods, and rainfall totals have increased significantly, as Grist reported in an article about the recent research.
The researchers said that without aerosol pollution — a slew of chemicals released mainly from the burning of dirty fuels — masking the effects of the changing climate, the extreme flood events that are becoming more frequent may have begun much earlier.
Scientists predict that as pollution levels continue to drop over the next decade, the effects of heat-trapping gases in the atmosphere will become more pronounced, unleashing more flooding and damaging storms.
"This somewhat rapid intensification of rainfall extremes is the new normal, at least for the next five years," Mark Risser, a Lawrence Berkeley National Lab research scientist and one of the paper's lead authors, told Grist.
Why is the drop in aerosol pollution concerning?
Aerosols help reduce the frequency of extreme rain and flood events, and they have also masked about 50% of the warming that would have been caused by heat-trapping gases, per NASA. Without the protective effect of aerosol air pollution, the world will become much wetter and warmer.
Per Grist, the authors of the paper published in Nature Communications said the southeastern U.S. bears the brunt of heavier rainfall and flooding events, some of which have been billion-dollar disasters.
Since the Environmental Protection Agency recently set stronger standards for toxic soot pollution, the authors worry that Americans in the southeast and other regions will endure even worse flooding and hurricanes over the next several decades — even as the standards also help people avoid health risks associated with the pollution, as Grist noted.
"We're looking at a situation where over the next 30 years, you could either keep masking, or you could reveal 50 percent more warming," Geeta Persad, a University of Texas at Austin Earth sciences assistant professor and an aerosols expert, told Grist.
What's being done to mitigate the risk of extreme weather?
While we may not be able to control the weather, we can at least take steps to reduce its impact on our communities. From improving forecasting equipment to better predict storms to designing flood-resilient towns popping up across the U.S., scientists and city planners are making efforts to help people adapt to the changing climate.
If you live in a flood-prone area, consider installing a rain garden to help soak up some of the water. Turning your garden into a backyard paradise can also save you tons of cash on lawn maintenance.
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