Actually, it's not the thermometers but their placement, which produces a false warming trend.
The official temperature record of continental United States comes from 1,221 stations of the National Weather Service, a department of the National Oceanic and Atmospheric Administration (NOAA). During the past few years, Anthony Watts, a 25-year veteran meteorologist, assisted by 650 volunteers inspected and photographically documented most of these surface temperature stations. As of June 21, 2009, they had covered 982 of the 1,221. And they were shocked by what they found.
In Watts' words, “We found stations located next to the exhaust fans of air conditioning units, surrounded by asphalt parking lots and roads, on blistering rooftops, and near sidewalks and buildings that absorb and radiate heat. We found 68 stations located at wastewater treatment plants, where the process of waste digestion causes temperatures to be higher than in surrounding areas.” Ninety percent of the stations fail to meet the National Weather Service's own requirement of being at least 30 meters (about 100 feet) from any artificial heating or reflecting/radiating heat source. Thus 9 out of every 10 stations were likely reporting higher temperatures because of their poor location.
Even worse, says Watts, “We observed that changes in the technology of temperature stations over time caused them to report a false warming trend. We found major gaps in the data record that were filled with data from nearby sites, a practice that propagates and compounds errors. We found adjustments to the data by both NOAA and another government agency (NASA) cause recent temperatures to look even higher.” [We have covered this latter point in a previous blog posting at http://www.amlibpub.com/liberty_blog_archive/2009_01_01_archive.html ]. And the U.S. record is thought to be the “best in the world.” So how much confidence can be placed in the worldwide network of surface temperature stations? Not to mention that they don't even cover the three-fourths of the earth covered by oceans.
Watts' report, published earlier this year, can be seen and downloaded at his website www.surfacestations.org. This includes photographs of all the stations surveyed thus far. Minnesota, where I live, furnishes some illustrative examples. The weather station at Detroit Lakes, Minnesota, is right in front of the exhaust from the compressor of an air conditioner. At Eveleth, Minnesota, the station is next to a wastewater treatment plant. The station at the Minneapolis airport is right between two runways. Temperature stations all over the world tend to be located at airports. In Spain, for example, 20 of 33 measuring stations are at airports. In Australia, three-fourths of the stations are at airports.
It is almost certainly true, too, that many other stations were originally located in acceptable sites that over the years were then altered by construction of parking lots, roads, buildings, and removal of trees or other vegetation. Certainly most of these have occurred in urban areas, resulting in the urban “heat island” effect, which has accompanied the increasing urbanization trend over many decades. Attempts to correct for this do not adequately account for the poor locations of measuring stations.
All this goes a long way toward explaining why surface temperature measurements are warmer than those from satellites. Satellites measurements are indisputably more accurate, but the global warming advocates always point to the surface measurements to justify their claims that the planet is heating up, because of their longer history; satellite measurements only go back to the late 1970s. The advocates also argue that the alleged global warming over the past century is due at least in part to human (anthropogenic) influence, rather than being simply natural. But that argument disappears when the errors from surface measuring stations are greater than the total warming, whether caused by man or nature. Anthony Watts concludes: “The errors in the record exceed by a wide margin the purported rise in temperature of 0.7 degrees C (about 1.2 F) during the twentieth century.”
Friday, August 21, 2009
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