Wednesday, May 3, 2006; Posted: 10:08 a.m. EDT (14:08 GMT)
WASHINGTON (AP) -- A nagging difference in temperature readings that had raised questions about global warming has been resolved, a panel of scientists reported Tuesday.
"This significant discrepancy no longer exists because errors in the satellite and radiosonde data have been identified and corrected," researchers said in the first of 21 assessment reports planned by the U.S. Climate Change Science Program.
The findings show clear evidence of human influences on climate due to changes in greenhouse gases, aerosols and stratospheric ozone.
There has been increasing concern about global climate change being caused by human activity, in particular the release of gases such as carbon dioxide into the atmosphere by automobiles and industrial activity.
But while temperature readings at the surface showed this increase, readings in the atmosphere taken by satellites and radiosondes -- instruments carried by weather balloons -- had shown little or no warming.
There are still some questions about the rate of atmospheric warming in the tropics, but overall the issue has been settled, said Thomas R. Karl, director of the National Climatic Data Center.
The White House Council on Environmental Quality issued a statement saying that the climate change program was established to reduce scientific uncertainties and "we welcome today's report because it represents success in doing so with respect to temperature trends."
Findings of the report include:
- Since the 1950s, all data show the Earth's surface and the low and middle atmosphere have warmed, while the upper stratosphere has cooled. Those changes were expected from computer models of the effects of greenhouse warming.
- Radiosonde readings for the midtroposphere -- the nearest portion of the atmosphere -- show it warming slightly faster than the surface, also an expected finding.
- The most recent satellite data also show tropospheric warming, though there is some disagreement among data sets. This may be caused by uncertainties in the observations, flaws in climate models or a combination. The researchers think it is a problem with the data collection.
- The observed patterns of change over the past 50 years cannot be explained by natural processes alone.
The report came a day after the government reported that greenhouse gases widely blamed for raising the planet's temperature are still building in the atmosphere.
The National Oceanic and Atmospheric Administration said Monday there was a continuing increase in carbon dioxide and nitrous oxide in the air last year, although methane leveled off. Overall, NOAA said, its annual greenhouse gas index "shows a continuing, steady rise in the amount of heat-trapping gases in the atmosphere."
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NOAA: Greenhouse gases continue to rise
Monday, May 1, 2006; Posted: 4:09 p.m. EDT (20:09 GMT)
WASHINGTON (AP) -- The greenhouse gases widely blamed for raising the planet's temperature are still building up in the atmosphere.
The National Oceanic and Atmospheric Administration said Monday there was a continuing increase in carbon dioxide and nitrous oxide in the air last year, though methane leveled off.
The agency said and there was a decline in two chlorofluorocarbons, gases blamed for the ozone hole over the Antarctic.
Overall, NOAA said, its annual greenhouse gas index "shows a continuing, steady rise in the amount of heat-trapping gases in the atmosphere."
The index was set at a base value of 1.0 in 1990. For 2005 it was 1.215, the agency said.
Greenhouse gases, produced by industry, automobiles and other engines, tend to trap heat from the sun at the planet's surface, reducing the amount of heat radiated back out into space.
The result has been a gradual increase of temperatures over recent decades, raising concerns that human activities will result in a damaging climate change.
Most of the increase is attributed to carbon dioxide, which the agency said accounts for 62 percent of radiative warming by greenhouse gases.
Carbon dioxide increased from an average of 376.8 parts per million in 2004 to 378.9 ppm in 2005. The preindustrial CO2 level is estimated to have been about 278 ppm.
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Kinda pathetic it took this long, I hope it's not too late.