Brookhaven Scientists Sample the Skies

To get the big picture on air pollution and climate, scientists have to think big — and small. Last summer, scientists from Brookhaven and other Department of Energy labs crisscrossed the skies above Western Pennsylvania to track the tiniest particles of air pollution.
— By Karen McNulty Walsh

Down-to-earth climate scientists agree that the level of atmospheric carbon dioxide (CO2), the best known “greenhouse gas,” is on the rise. But how much a given rise in CO2 will raise our planet’s temperature is still the subject of intense research — and heated debate.

Gulfstream G-1 research aircraft.

One complicating factor is a lack of understanding of the influence of atmospheric aerosols, tiny particles released into the air from industrial processes like fossil-fuel combustion at the same time as CO2. Aerosol particles scatter and absorb light and modify the properties of clouds, making them brighter and thus able to reflect more sunlight before it reaches Earth’s surface. Aerosols could therefore be masking some or even much of the influence of the greenhouse gases — to the point where we might be seeing only the “tip” of the greenhouse effect “iceberg.” But no one knows just how much global warming is “hiding beneath the surface.”

To make more accurate estimates of the magnitude of warming we may face in the future, scientists need more information about the role of aerosols.

As part of the effort to gather that information, scientists from the three Department of Energy national laboratories — Argonne (ANL), Brookhaven (BNL), and Pacific Northwest (PNNL) — took to the skies above Western Pennsylvania for a month of air-sampling flights in the summer of 2004 to track the levels of aerosol pollutants.
The research was part of the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) experiment, an effort by many separate institutions and government agencies like the National Atmospheric and Oceanographic Administration (NOAA), the National Aeronautics and Space Administration (NASA), the University of New Hampshire, and others in Canada and Europe, to conduct a joint regional air quality and climate study of unprecedented scope.