Science and Medicine

Our findings have significant policy implications for sustainable development and water resources, especially for those developing regions susceptible to extreme events such as drought and flood.

Increases in air pollution and other particulate matter in the atmosphere can strongly affect cloud development in ways that reduce precipitation in dry regions or seasons, while increasing rain, snowfall and the intensity of severe storms in wet regions or seasons, says a new study by a University of Maryland-led team of researchers.

The research provides the first clear evidence of how aerosols—soot, dust and other small particles in the atmosphere—can affect weather and climate; and the findings have important implications for the availability, management and use of water resources in regions across the United States and around the world, say the researchers and other scientists.

“Using a 10-year dataset of extensive atmosphere measurements from the U.S. Southern Great Plains research facility in Oklahoma [run by the Department of Energy’s Atmospheric Radiation Measurement program]—we have uncovered, for the first time, the long-term, net impact of aerosols on cloud height and thickness, and the resultant changes in precipitation frequency and intensity,” said Zhanqing Li, a professor of atmospheric and oceanic science at Maryland and lead author of the study.

Read more: Rising Air Pollution Worsens Drought, Flooding, New Study Finds

Scientists at NOAA’s Earth System Research Laboratory prepare the AGGI each year from atmospheric data collected through an international cooperative air sampling network of more than 100 sites around the world.

NOAA’s updated Annual Greenhouse Gas Index, which measures the direct climate influence of many greenhouse gases such as carbon dioxide and methane, shows a continued steady upward trend that began with the Industrial Revolution of the 1880s.

Started in 2004, the AGGI reached 1.29 in 2010. That means the combined heating effect of long-lived greenhouse gases added to the atmosphere by human activities has increased by 29 percent since 1990, the “index” year used as a baseline for comparison. This is slightly higher than the 2009 AGGI, which was 1.27, when the combined heating effect of those additional greenhouse gases was 27 percent higher than in 1990.

“The increasing amounts of long-lived greenhouse gases in our atmosphere indicate that climate change is an issue society will be dealing with for a long time,” said Jim Butler, director of the Global Monitoring Division of NOAA’s Earth System Research Laboratory in Boulder, Colo. “Climate warming has the potential to affect most aspects of society, including water supplies, agriculture, ecosystems and economies. NOAA will continue to monitor these gases into the future to further understand the impacts on our planet.”

Read more: Greenhouse Gas Index Continues to Climb