Earth & Environment
The supercontinent of the future, pollutants from laundry detergent and more in this week’s news
By Science News
Clouds intensify soot’s Arctic heating
Reining in soot production could dramatically slow Arctic warming, Mark Jacobson of Stanford University reported August 31 in Denver at the American Chemical Society’s national meeting. Soot’s presence in water droplets heats clouds much more than it does the black carbon particles between cloud droplets, new computer analyses show — which Jacobson says “helps to explain the burning off of clouds in polluted regions.” Once clouds disappear, more sunlight reaches the surface to melt sea ice and warm Arctic waters. But curbing all soot that now wafts into the Arctic could within 15 years eliminate 15 to 20 percent of the total warming contribution to the region, which could reduce the net temperature rise by 50 percent, his computer projections indicate. —Janet Raloff
Bedrock can help the climate
Researchers from the University of California, Davis offer data that could overturn the conventional wisdom about where new nitrogen in land-based ecosystems comes from. It’s supposed to come from the atmosphere. But forests and local soils underlain with nitrogen-rich sedimentary rock contain 50 percent more nitrogen, a fertilizer, than do those atop nitrogen-poor rock, the scientists report in the Sept. 1 Nature. These researchers fingerprinted the bonus nitrogen to the weathering of bedrock below. Forests and soils over nitrogen-releasing rock also contained substantially more carbon than in nitrogen-poor areas, the scientists found, demonstrating that bedrock can dramatically boost the carbon-sequestering climate benefits of some forests. —Janet Raloff