From the University of Washington:
Women living in areas with higher levels of air pollution have a greater risk of developing cardiovascular disease and subsequently dying from cardiovascular causes, according to a University of Washington study appearing in the Feb. 1 issue of The New England Journal of Medicine. The study is one of the largest of its kind, involving more than 65,000 Women's Health Initiative Observational Study participants, age 50 to 79, living in 36 cities across the United States.
UW researchers studied women who did not initially have cardiovascular disease, following them for up to nine years to see who went on to have a heart attack, stroke, or coronary bypass surgery, or died from cardiovascular causes. They linked this health information with the average outdoor air pollution levels near each woman's home, and found that higher pollution levels posed a significant hazard – much higher than previously thought – for development of cardiovascular disease.
The researchers studied levels of fine particulate matter, which are tiny airborne particles of soot or dust, and can come from a variety of sources, like vehicle exhaust, coal-fired power plants, industrial sources, and wood-burning fireplaces. These particles are less than 2.5 microns in diameter -- about 30 to 40 of them would equal the diameter of a human hair. Particulate matter levels are monitored and regulated by the U.S. Environmental Protection Agency (EPA). They're typically invisible to the human eye once they're in the atmosphere, though they may be visible in dense clouds as they come out of a tailpipe, smokestack or chimney, and are responsible for urban haze.
"These soot particles, which are typically created by fossil-fuel combustion in vehicles and power plants, can contain a complex mix of chemicals," explained Dr. Joel Kaufman, professor of environmental & occupational health sciences, epidemiology, and medicine at the UW, and leader of the study. "The tiny particles – and the pollutant gases that travel along with them – cause harmful effects once they are breathed in."
Fine particulate matter is measured in micrograms (or millionths of a gram) per cubic meter; cities in the study had average levels of fine particulate matter ranging from about 4 to nearly 20 micrograms per cubic meter. The researchers found that each 10-unit increase in fine particulate matter level was linked to a 76 percent increase in the risk of death from cardiovascular disease, after taking into account known risk factors such as blood pressure, cholesterol, and smoking. Higher long-term average levels of fine particulate matter also led to a higher overall risk of cardiovascular disease events, including stroke and heart attack.
They also found that local differences in particulate matter levels within a city, as well as exposure differences between cities, translate to a higher or lower risk of cardiovascular disease and related death.
"Our findings show that both what city a woman lived in, and where she lived in that city, affected her exposure level and her disease risk," said Kristin Miller, first author of the study and a doctoral student in epidemiology at the UW.
Previous studies have found apparent links between airborne particulate matter and cardiovascular disease, but this study was the first to look specifically at new cases of cardiovascular disease in previously healthy subjects and local air pollution levels within metropolitan areas. Researchers used data from the multi-site Women's Health Initiative Observational Study, which is funded by the National Heart Lung and Blood Institute of the National Institutes of Health (NIH), and coordinated through a center based at the Fred Hutchinson Cancer Research Center in Seattle. The EPA and the National Institute of Environmental Health Sciences provided funding for the study of the effects of air pollution.
Scientists don't understand exactly how fine particulate matter may be leading to cardiovascular disease, but some believe that the soot particles are accelerating atherosclerosis, or hardening of the arteries, which is the major precursor of heart disease.
"This could be a cellular and biochemical process that starts in the lung and then proceeds from there into the cardiovascular system," Kaufman explained. "Or it could be that these very small particles actually enter the blood stream through vessels in the lung, and then begin affecting blood vessels throughout the body."
Kaufman is leading a major new EPA-funded study to uncover these mechanisms – an air-pollution study based on the NIH's Multi-Ethnic Study of Atherosclerosis, or MESA. The MESA Air Pollution Study tackles two key areas for understanding this problem, Kaufman said: investigating the mechanisms through which particulate matter leads to cardiovascular disease, and identifying the sources of pollution that cause the problem. "Preventing these effects requires reducing the pollution at the source," Kaufman said.
The implications of this connection could be very significant.
"More than one out of three deaths in the United States are due to cardiovascular disease – it's the leading cause of death," Miller said. "If the annual average concentration of fine particulate air pollution can be reduced, it would potentially translate on a national scale to the prevention or delay of thousands and thousands of heart attacks, strokes, and bypass surgeries, not to mention fewer early deaths."
An editorial from researchers at the Harvard School of Public Health and Brigham and Women's Hospital will accompany the study in the Feb. 1 issue of the journal. In that editorial, the authors suggest public health interventions to address this problem, as well as a tightening of the EPA standards regulating fine particulate matter pollution.
In addition to Kaufman and Miller, the study included researchers from the UW School of Medicine and the School of Public Health and Community Medicine, the Fred Hutchinson Cancer Research Center, and Harborview Medical Center, all in Seattle.
NOTE: To determine the average annual concentration of fine particulate matter for a particular city or county, visit the EPA's Air Trends Web site and look for "PM 2.5 Wtd AM" in the tables provided. The most recent data available from the EPA is from 2005. http://www.epa.gov/airtrends/factbook.html
Wednesday, January 31, 2007
Monday, January 29, 2007
Glaciers melting at unprecedented speed
Published: January 29 2007
Mountain glaciers around the world are melting at an unprecedented rate, according to new scientific data that will reinforce pressure on governments to take stronger action on global warming.
The World Glacier Monitoring Service in Zurich, Switzerland, said preliminary estimates for 2005 based on monitoring of 30 “reference” glaciers showed an average loss of 0.6 metres in ice thickness.
The 2005 figures match the average annual loss rate since 2000, which is one-and-a-half times the average annual ice loss in the 1990s and three times the loss rate of the 1980s, the WGMS said.
Mountain glaciers around the world are melting at an unprecedented rate, according to new scientific data that will reinforce pressure on governments to take stronger action on global warming.
The World Glacier Monitoring Service in Zurich, Switzerland, said preliminary estimates for 2005 based on monitoring of 30 “reference” glaciers showed an average loss of 0.6 metres in ice thickness.
The 2005 figures match the average annual loss rate since 2000, which is one-and-a-half times the average annual ice loss in the 1990s and three times the loss rate of the 1980s, the WGMS said.
Experts fear upcoming global warming report may understate problem
WASHINGTON (AP) -- Later this week in Paris, climate scientists will issue a dire forecast for the planet that warns of slowly rising sea levels and higher temperatures.
But that may be the sugarcoated version.
Early and changeable drafts of their upcoming authoritative report on climate change foresee smaller sea level rises than were projected in 2001 in the last report. Many top U.S. scientists reject these rosier numbers.
Those calculations don't include the recent, and dramatic, melt-off of big ice sheets in two crucial locations:
They "don't take into account the gorillas -- Greenland and Antarctica," said Ohio State University earth sciences professor Lonnie Thompson, a polar ice specialist. "I think there are unpleasant surprises as we move into the 21st century."
Michael MacCracken, who until 2001 coordinated the official U.S. government reviews of the international climate report on global warming, has fired off a letter of protest over the omission.
The melting ice sheets in Greenland and Antarctica are a fairly recent development that has taken scientists by surprise. They don't know how to predict its effects in their computer models. But many fear it will mean the world's coastlines are swamped much earlier than most predict.
Others believe the ice melt is temporary and won't play such a dramatic role.
That debate may be the central one as scientists and bureaucrats from around the world gather in Paris to finish the first of four major global warming reports by the Intergovernmental Panel on Climate Change. The panel was created by the United Nations in 1988.
After four days of secret word-by-word editing, the final report will be issued Friday.
The early versions of the report predict that by 2100 the sea level will rise anywhere between 5 and 23 inches. That's far lower than the 20 to 55 inches forecast by 2100 in a study published in the peer-review journal Science this month. Other climate experts, including NASA's James Hansen, predict sea level rise that can be measured by feet more than inches.
The report is also expected to include some kind of proviso that says things could be much worse if ice sheets continue to melt.
The prediction being considered this week by the IPCC is "obviously not the full story because ice sheet decay is something we cannot model right now, but we know it's happening," said Stefan Rahmstorf, a climate panel lead author from Germany who made the larger prediction of up to 55 inches of sea level rise. "A document like that tends to underestimate the risk," he said.
"This will dominate their discussion because there's so much contentiousness about it," said Bob Corell, chairman of the Arctic Climate Impact Assessment, a multinational research effort. "If the IPCC comes out with significantly less than one meter (about 39 inches of sea level rise), there will be people in the science community saying we don't think that's a fair reflection of what we know."
In the past, the climate change panel didn't figure there would be large melt of ice in west Antarctica and Greenland this century and didn't factor it into the predictions. Those forecasts were based only on the sea level rise from melting glaciers (which are different from ice sheets) and the physical expansion of water as it warms.
But in 2002, Antarctica's 1,255-square-mile Larsen B ice shelf broke off and disappeared in just 35 days. And recent NASA data shows that Greenland is losing 53 cubic miles of ice each year -- twice the rate it was losing in 1996.
Even so, there are questions about how permanent the melting in Greenland and especially Antarctica are, said panel lead author Kevin Trenberth, chief of climate analysis at the National Center for Atmospheric Research in Colorado.
While he said the melting ice sheets "raise a warning flag," Trenberth said he wonders if "some of this might just be temporary."
University of Alabama at Huntsville professor John Christy said Greenland didn't melt much within the past thousand years when it was warmer than now. Christy, a reviewer of the panel work, is a prominent so-called skeptic. He acknowledges that global warming is real and man-made, but he believes it is not as worrisome as advertised.
Those scientists who say sea level will rise even more are battling a consensus-building structure that routinely issues scientifically cautious global warming reports, scientists say.
The IPCC reports have to be unanimous, approved by 154 governments -- including the United States and oil-rich countries such as Saudi Arabia -- and already published peer-reviewed research done before mid-2006.
Rahmstorf, a physics and oceanography professor at Potsdam University in Germany, says, "In a way, it is one of the strengths of the IPCC to be very conservative and cautious and not overstate any climate change risk."
But that may be the sugarcoated version.
Early and changeable drafts of their upcoming authoritative report on climate change foresee smaller sea level rises than were projected in 2001 in the last report. Many top U.S. scientists reject these rosier numbers.
Those calculations don't include the recent, and dramatic, melt-off of big ice sheets in two crucial locations:
They "don't take into account the gorillas -- Greenland and Antarctica," said Ohio State University earth sciences professor Lonnie Thompson, a polar ice specialist. "I think there are unpleasant surprises as we move into the 21st century."
Michael MacCracken, who until 2001 coordinated the official U.S. government reviews of the international climate report on global warming, has fired off a letter of protest over the omission.
The melting ice sheets in Greenland and Antarctica are a fairly recent development that has taken scientists by surprise. They don't know how to predict its effects in their computer models. But many fear it will mean the world's coastlines are swamped much earlier than most predict.
Others believe the ice melt is temporary and won't play such a dramatic role.
That debate may be the central one as scientists and bureaucrats from around the world gather in Paris to finish the first of four major global warming reports by the Intergovernmental Panel on Climate Change. The panel was created by the United Nations in 1988.
After four days of secret word-by-word editing, the final report will be issued Friday.
The early versions of the report predict that by 2100 the sea level will rise anywhere between 5 and 23 inches. That's far lower than the 20 to 55 inches forecast by 2100 in a study published in the peer-review journal Science this month. Other climate experts, including NASA's James Hansen, predict sea level rise that can be measured by feet more than inches.
The report is also expected to include some kind of proviso that says things could be much worse if ice sheets continue to melt.
The prediction being considered this week by the IPCC is "obviously not the full story because ice sheet decay is something we cannot model right now, but we know it's happening," said Stefan Rahmstorf, a climate panel lead author from Germany who made the larger prediction of up to 55 inches of sea level rise. "A document like that tends to underestimate the risk," he said.
"This will dominate their discussion because there's so much contentiousness about it," said Bob Corell, chairman of the Arctic Climate Impact Assessment, a multinational research effort. "If the IPCC comes out with significantly less than one meter (about 39 inches of sea level rise), there will be people in the science community saying we don't think that's a fair reflection of what we know."
In the past, the climate change panel didn't figure there would be large melt of ice in west Antarctica and Greenland this century and didn't factor it into the predictions. Those forecasts were based only on the sea level rise from melting glaciers (which are different from ice sheets) and the physical expansion of water as it warms.
But in 2002, Antarctica's 1,255-square-mile Larsen B ice shelf broke off and disappeared in just 35 days. And recent NASA data shows that Greenland is losing 53 cubic miles of ice each year -- twice the rate it was losing in 1996.
Even so, there are questions about how permanent the melting in Greenland and especially Antarctica are, said panel lead author Kevin Trenberth, chief of climate analysis at the National Center for Atmospheric Research in Colorado.
While he said the melting ice sheets "raise a warning flag," Trenberth said he wonders if "some of this might just be temporary."
University of Alabama at Huntsville professor John Christy said Greenland didn't melt much within the past thousand years when it was warmer than now. Christy, a reviewer of the panel work, is a prominent so-called skeptic. He acknowledges that global warming is real and man-made, but he believes it is not as worrisome as advertised.
Those scientists who say sea level will rise even more are battling a consensus-building structure that routinely issues scientifically cautious global warming reports, scientists say.
The IPCC reports have to be unanimous, approved by 154 governments -- including the United States and oil-rich countries such as Saudi Arabia -- and already published peer-reviewed research done before mid-2006.
Rahmstorf, a physics and oceanography professor at Potsdam University in Germany, says, "In a way, it is one of the strengths of the IPCC to be very conservative and cautious and not overstate any climate change risk."
Wednesday, January 10, 2007
Federal government: 2006 hottest year on record
We've been feeling the heat, and now the federal government confirms it:
2006 was the hottest year on record:
http://www.noaanews.noaa.gov/stories2007/s2772.htm
2006 was the hottest year on record:
http://www.noaanews.noaa.gov/stories2007/s2772.htm
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