What happened to global cooling?
Climate change deniers have in recent years claimed that there has been a global cooling trend over the past decade, providing evidence that climate is influenced by natural cycles and not by increases of carbon dioxide and other greenhouse gases due to human activities. However, the annual summary just released by NASA shows that, averaged over the whole globe, 2009 was tied as the second warmest year in 130 years of global instrumental temperature records (2005 was the warmest). Furthermore, the recently
concluded decade was the fourth in a row that was decidedly warmer than the preceding
decade. This is all explained by NASA scientists, along with the reasons for the recent cold weather in the U.S., in "If it's that warm, how come it's so damned cold?". This is trend is clearly not caused by solar activity, which is the lowest it has been in over a century.
Faced with these results, deniers are now attacking the integrity of the data. In anticipation of the release of the 2009 findings by NASA and NOAA, a San Diego TV meteorologist is alleging that scientists from these two U.S. agencies improperly manipulated temperature monitoring data. The NOAA National Climate Data Center provides a straightforward description of how the data from long term temperature monitoring are adjusted for measurements changes and the urban heat island effect and to extend
estimates to regions poorly covered by stations in order to compute the global average. There is nothing nefarious here, just rigorous analysis of the data available.
But the most reliable indicator that Earth is continuing to warm comes from the oceans, which store much more heat than the atmosphere. The total heat content of the oceans has been more or less steadily rising since 1970 and over the past nine years through both cooler years and warmer years. This is causing the volume of the oceans to expand. The volume is also increasing as a result of the melting of glaciers on the continents and now, based on recent evidence, the melting of the massive ice sheets on Greenland and Antarctica. Sea level, which was rising at a rate of about 0.7 mm/year during the 19th century and averaged 1.8 mm/year over the 20th century, has been recently rising at a rate of 3.4 mm/year, or nearly five times faster than about 100 years ago.
Posted by: c0lnag0 | January 21, 2010 11:41 PM
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