New Findings on Global Warming

LIMITING METHANE, SOOT COULD CURB GLOBAL WARMING

(ENS)- A recent study suggests that reducing methane emissions and soot could significantly curb global warming. The Goddard Institute for Space Studies, a division of the National Aeronautics and Space Administration (NASA) says technologies are within reach to reduce methane in ways that are cheaper and faster than reducing carbon dioxide. Global warming is caused by carbon dioxide (CO₂) emitted by the combustion of coal, oil and gas, and by other greenhouse gases including chlorofluorocarbons (CFCs), methane, tropospheric ozone and black carbon soot particles. Methane is a naturally occurring gas, a product of a variety of biological processes. But the unnatural concentration of the gas from human-induced factors is the problem. Methane can enter the atmosphere as a byproduct of the decomposition of garbage, such as from landfills, rice cultivation, industrial production and cattle herds. Meanwhile, a recent study published in the journal Nature indicates that soot may be the second biggest contributor to global warming, behind CO₂. �Soot, or black carbon, may be responsible for 15 to 30 percent of global warming, yet it�s not even considered in any of the discussions about controlling climate change,� says Stanford Professor Mark Jacobson, an assistant professor of civil and environmental engineering and author of the study. Some 90 percent of soot comes from the consumption of fossil fuels, particularly diesel fuel, coal, jet fuel, natural gas and kerosene, as well as the burning of wood and other biomass when land is cleared,� said Jacobson.

BIOMASS BURNING �CANNOT GO ON�

(ENS) �Pollution may be seriously weakening the Earth�s water cycle, reducing rainfall and threatening fresh water supplies, says a recent study by researchers at the Scripps Institution of Oceanography. The scientists suggest that tiny particles of soot and other pollutants are having a far greater effect on the planet�s hydrological cycle than previously realized. Tiny aerosols, primarily made up of black carbon, can lead to a weaker hydrological cycle, which affects fresh water availability and quality on which human life depends, the authors argue. The study is based on results obtained during the International Indian Ocean Experiment (INDOEX), and appeared in the journal Science. �Through INDOEX we found that aerosols are cutting down sunlight going into the ocean,� said one lead scientist. �The energy for the hydrological cycle comes from sunlight. As sunlight heats the ocean, water escapes into the atmosphere and falls out as rain. So as aerosols cut down sunlight by large amounts, they may be spinning down the hydrological cycle of the planet.� Another scientist noted that aerosol particulates may be suppressing rain over polluted regions. Within clouds, aerosols can limit the size of cloud droplets, stifling the development of the larger droplets required for raindrops. If pollutants cut back on rain and snowfall, it could directly affect the replenishment of the world�s major stores of freshwater, including lakes, groundwater supplies, glaciers and high elevation snow pack. If humans continue to draw down these stores at a faster rate than they are replenished, access to fresh water could become the most crucial problem facing civilization.