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Global warming worsening as greenhouse gas grows

WASHINGTON -- The world's climate is not only continuing to warm, it's adding heat-trapping greenhouse gases even faster than in the past, researchers said Tuesday.

Indeed, the global temperature has been warmer than the 20th century average every month for more than 25 years, they said at a teleconference.

''The indicators show unequivocally that the world continues to warm,'' Thomas R. Karl, director of the National Climatic Data Center, said in releasing the annual State of the Climate report for 2010.

''There is a clear and unmistakable signal from the top of the atmosphere to the depths of the oceans,'' added Peter Thorne of the Cooperative Institute for Climate and Satellites, North Carolina State University.

Carbon dioxide increased by 2.60 parts per million in the atmosphere in 2010, which is more than the average annual increase seen from 1980-2010, Karl added. Carbon dioxide is the major greenhouse gas accumulating in the air that atmospheric scientists blame for warming the climate.

The warmer conditions are consistent with events such as heat waves and extreme rainfall, Karl said at a teleconference. However, it is more difficult to make a direct connection with things like tornado outbreaks, he said.

''Any single weather event is driven by a number of factors, from local conditions to global climate patterns and trends. Climate change is one of these,'' he said. ''It is very likely that large-scale changes in climate, such as increased moisture in the atmosphere and warming temperatures, have influenced -- and will continue to influence -- many different types of extreme events, such as heavy rainfall, flooding, heat waves and droughts.

The report, being published by the American Meteorological Society, lists 2010 as tied with 2005 for the warmest year on record, according to studies by the National Oceanic and Atmospheric Administration and NASA. A separate analysis, done in Britain, lists 2010 as second warmest.