November 11, 2010

Leaking underground CO2 storage could contaminate drinking water

Leaks from carbon dioxide injected deep underground to help fight climate change could bubble up into drinking water aquifers near the surface, driving up levels of contaminants in the water tenfold or more in some places, according to a study by Duke University scientists.
Based on a year-long analysis of core samples from four drinking water aquifers, "We found the potential for contamination is real, but there are ways to avoid or reduce the risk," says Robert B. Jackson, Nicholas Professor of Global Environmental Change and professor of biology at Duke.
"Geologic criteria that we identified in the study can help identify locations around the country that should be monitored or avoided," he says. "By no means would all sites be susceptible to problems of water quality."

November 10, 2010

Extreme global warming in the ancient past

Variations in atmosphere carbon dioxide around 40 million years ago were tightly coupled to changes in global temperature, according to new findings published in the journal Science. The study was led by scientists at Utrecht University, working with colleagues at the NIOZ Royal Netherlands Institute for Sea Research and the University of Southampton.
"Understanding the relationship between the Earth's climate and atmospheric carbon dioxide in the geological past can provide insight into the extent of future global warming expected to result from carbon dioxide emission caused by the activities of humans," said Dr Steven Bohaty of the University of Southampton's School of Ocean and Earth Science (SOES) based at the National Oceanography Centre in Southampton.
It has been known for some time that the long-term warmth of the Eocene (~56 to 34 million years ago) was associated with relatively high atmospheric carbon dioxide levels. However, scientists were previously unable to demonstrate tight-coupling between variations in atmospheric carbon dioxide and shorter-term changes in global climate.

November 7, 2010

Volcanic eruptions affect rainfall over Asian monsoon region

Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air.
Some suspect that extended "volcanic winters" from gigantic eruptions helped kill off dinosaurs and Neanderthals.
In the summer following Indonesia's 1815 Tambora eruption, frost wrecked crops as far away as New England, and the 1991 blowout of the Philippines' Mount Pinatubo lowered average global temperatures by 0.7 degrees F--enough to mask the effects of greenhouse gases for a year or so.
Now, in research funded by the National Science Foundation (NSF)'s Division of Atmospheric and Geospace Sciences, scientists have discovered that eruptions also affect rainfall over the Asian monsoon region, where seasonal storms water crops for nearly half of Earth's population.
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