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Ocean temperatures might have risen even higher during the last century if it weren't for volcanoes that spewed ashes and aerosols into the upper atmosphere, researchers have found. The eruptions also offset a large percentage of sea level rise caused by human activity. Using 12 new state-of-the-art climate models, the researchers found that ocean warming and sea level rise in the 20th century were substantially reduced by the 1883 eruption of the Krakatoa volcano in Indonesia. Volcanic aerosols blocked sunlight and caused the ocean surface to cool. "That cooling penetrated into deeper layers of the ocean, where it remained for...

China has darkened over the past half-century. Where has all the sunshine gone? The usual suspect, at least to a climatologist, would be cloud cover. But in the most comprehensive study to date of overcast versus cloud-free days in China, a team led by the Department of Energy's Pacific Northwest National Laboratory, reporting in the current advance online issue of Geophysical Research Letters, has found that cloud cover has been decreasing for the past 50 years. Eliminating clouds from the dimming equation now leaves little doubt that human activity, in the form of a nine-fold increase in fossil fuel emissions...

Close window Published online: 21 December 2005; | doi:10.1038/news0051219-11 Aerosols cool more than expectedResearchers measure smog's effect on counteracting global warming.Quirin Schiermeier Hot times: cities would be even warmer if not covered by a blanket of smog. © Punchstock Cleaning the air could accelerate global warming, according to a new study. The particles in the soot and haze from industrial and domestic fires, called aerosols, cause respiratory diseases and other health problems for people in polluted areas, including many Asian cities. But aerosols also dim the sky over land and sea, and so cool the planet. By scattering and...

China's rapid economic growth and industrialization is posing a major challenge to the environment with air pollution likely to rise five-fold in 15 years, officials warned Monday. "In the future 15 years, the population of China will reach 1.46 billion and the GDP will double, the pollution load will increase by four to five times according to the present resource consumption rate and pollution control level," said Zhang Lijun, vice minister of China's environmental agency SEPA. Zhang was speaking at an air pollution conference organized by the State Environmental Protection Administration (SEPA), the US Environmental Protection Agency, the environmental directorate...

A researcher has discovered unexpectedly large amounts of dandruff and other flaking skin, fur, pollen and similar materials in air pollutants known as aerosols. Aerosols, tiny particles in the air, are widely studied because they are an important factor in regulating climate, variously absorbing heat to warm the air and reflecting sunlight to cool it. They are also important in forming rain and snow. But the amount of cellular material — bacteria, plant fragments, spores, fungi and so forth — had been thought to be only a small proportion compared with mineral dusts, clay and sea salt. Now, Ruprecht Jaenicke...

A gaping hole in the ozone layer over Antarctica appears to have shrunk by about 20 percent from last year's record-breaking size, New Zealand scientists said on Friday. The National Institute of Water & Atmospheric Research (NIWA) said its measurements backed up NASA satellite data showing the hole peaked at about 9 million sq miles compared with 11 million sq miles in 2003. The ozone layer sits about 9-19 miles above the earth, filtering harmful ultraviolet rays that can cause skin cancer. Industrial chemicals containing chlorine and bromine used in refrigerators and aerosols have been blamed for thinning the layer...

WASHINGTON - Scientists call it "global dimming," little-known trend that may be making the world darker than it used to be. Thanks to thicker clouds and growing air pollution, much of the Earth's surface is receiving about 15 percent less sunlight than it did 50 years ago, according to Michael Roderick, a climate researcher at Australian National University in Canberra. "Global dimming means that the transmission of sunlight through the atmosphere is decreasing," Roderick said. "Just look out the window when you fly into New York or to California - it's dimmer," said Beate Liepert, a climatologist at the Lamont-Doherty...