In a Capitol Hill briefing on the recently released State of the Climate in 2010 report, Tom Karl, Director of NOAA’s National Climatic Data Center, rebutted the skeptic argument that global warming has stopped. During the question and answer period, Karl noted that long-term predictions of climate change indicate that areas around the US-Canadian border will receive more precipitation, while areas around the US-Mexican border will become drier than they have been in the past. We are seeing weather/climate patterns in the US that are consistent with that.
Post by Katherine O’Konski and Jamal Knight
In a July 11 briefing (PowerPoint slides, 8.9 MB) in the U.S. Capitol Building, Tom Karl, Director of NOAA’s National Climatic Data Center and Chairman of the U.S. Global Change Research Program interagency committee, outlined the State of the Climate in 2010 report and discussed the new temperature ‘normals’ for 1981-2010.
The goal of the SOTC report is to “document the weather and climate events of the most recent calendar year and put them into accurate historical perspective, with a particular focus on unusual or anomalous events.” NOAA’s press release notes that the peer-reviewed report was issued in coordination with the American Meteorological Society, and was compiled by 368 authors from 45 countries.
The report describes trends in 41 global-scale climate indicators. As Mr. Karl explained during the question and answer session, these key indicators are defined and discussed in a 2003 document on the Global Climate Observing System issued by the World meteorological Organization. In order to maintain a broader description of the climate system, the State of the Climate report attempts to add new indicators each year. This year, four are new. The new indicators include atmospheric surface water temperature, levels of greenhouse gases including perfluorocarbons, ocean salinity, and groundwater levels. Stratospheric temperature, snow cover, levels of greenhouse gases, air temperature, and ocean salinity are a few of the other indicators used to monitor the behavior of the physical climate system.
These indicators on a global scale constitute an “unmistakable signal that there is warming from the top of the atmosphere to the bottom of the oceans,” Karl concluded. 2010 was tied for the warmest year on record with 2005, while Greenland’s ice sheet lost the most mass in the last ten years. Changes to the Arctic’s climate are “occurring faster than in most of the rest of the world,” he said. The September Arctic sea ice extent was the third smallest of the past 30 years.
The report explains that extreme variability in weather patterns seen in 2010 can be attributed in part to “the transition from a warm El Niño climate pattern at the beginning of the year, to a strong version of its cool sister pattern, La Niña.” This resulted in a very slow cyclone season in the Pacific, and flooding inAustraliabeginning December 2010. In addition, the Arctic Oscillation, which most often confines colder air temperatures to northern latitudes, switched to a high-undulating negative phase. This resulted in profound warmth in parts of northern North America, Greenland, and Asia, while simultaneously bringing record cold to the US and Western Europe during winter 2009-10 and 2010-11. Interestingly, the Southern Hemisphere Annular Mode, a phenomenon related to the storm track circling the southern hemisphere, resulted in record maximum ice volumes in the Antarctic.
During the question and answer period, Mr. Karl was given the chance to explain that long-term predictions of climate change indicate that areas around the US-Canadian border will receive more precipitation, while areas around the US-Mexican border will become drier than they have been in the past.
He was also given a chance to address the skeptic argument that the climate has not significantly warmed since 1998. This argument arises because UK data shows 1998, a strong El Niño year, to have the highest global average surface temperature on record, with US data showing 2005 and 2010 tied for highest temperatures. While some have argued from these data points that global warming has stopped during the past decade, Karl said that the longer-term trend of rising temperatures, along with data from multiple climate indicators, refute that argument.