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  • From: "Kevin Ancell" <kancell AT goodearthgardens.com>
  • To: "Market Farming" <market-farming AT franklin.oit.unc.edu>
  • Subject: Global Warming "Theory"
  • Date: Fri, 13 Apr 2001 06:02:30 -0700


New evidence casts doubt on global warming
http://www.heartland.org/environment/apr01/evidence.htm

Claims are "based on false data," international team of scientists says

by Robert Matthews

Fresh doubt has been cast on evidence for global warming following the
discovery that a key method of measuring temperature change has exaggerated
the warming rate by almost 40 percent.
Studies of temperature records dating back more than a century have seemed
to indicate a rise in global temperature of around 0.5C, with much of it
occurring since the late 1970s. This has led many scientists to conclude
global warming is under way, with the finger of blame usually pointed at
man-made emissions of such greenhouse gases as carbon dioxide.
Now an international team of scientists, including researchers from the Met
Office in Bracknell, Berkshire, United Kingdom, has found serious
discrepancies in the temperature measurements, suggesting that the amount of
global warming is much less than previously believed.

Measuring water, not air
The concern focuses on the temperature of the atmosphere over the oceans,
which cover almost three-quarters of the Earth's surface. While scientists
use standard weather station instruments to detect warming on land, they
have been forced to rely on the crews of ships to make measurements over the
vast ocean regions.
Crews have taken the temperature by dipping buckets into the sea or using
water flowing into the engine intakes. Scientists have assumed there is a
simple link between the temperature of seawater and that of the air above
it.
However, after analyzing years of data from scientific buoys in the Pacific
that measure sea and air temperatures simultaneously, the team has found no
evidence of a simple link. Instead, the seawater measurements have
exaggerated the amount of global warming over the seas, with the real
temperature having risen less than half as fast during the 1970s than the
standard measurements suggest.
Reporting their findings in the influential journal Geophysical Research
Letters, the scientists say the exact cause of the discrepancy is not known.
One possibility is that the atmosphere responded faster than the sea to
cooling events such as volcanic eruptions.

A big cut
The findings have major implications for the climate change debate because
sea temperature measurements are a key part of global warming calculations.
According to the team, replacing the standard seawater data with the
appropriate air data produces a big cut in the overall global warming rate
during the last 20 years, from around 0.18C per decade to 0.13C.
This suggests that the widely quoted global warming figure used to persuade
governments to take action on greenhouse gas emissions exaggerates the true
warming rate by almost 40 percent. The team is now calling for climate
experts to switch from seawater data to sea-air temperature measurements.
One member of the team, David Parker, of the Hadley Centre for Climate
Prediction and Research at the Met Office, said the discovery of the
discrepancy "shows we don't understand everything, and that we need better
observations--all branches of science are like that." Yet according to
Parker, the new results do not undermine the case for global warming: "It is
raising questions about the interpretation of the sea-surface data."
Even so, the findings will be seized on by skeptics as more evidence that
scientists have little idea about the current rate of global warming, let
alone its future rate. Climate experts are still trying to explain why
satellites measuring the temperature of the Earth have detected little sign
of global warming, despite taking measurements during supposedly the warmest
period on record.
Some researchers suspect the fault may again lie with the ground-based
temperature measurements. They say many of the data come from stations
surrounded by growing urban sprawl, whose warmth could give a misleading
figure. A study of data taken around Vienna, Austria, between 1951 and 1996
found that the air temperature rose by anything from zero to 0.6C, depending
on precisely where the measurements were made.





Robert Matthews is a staff reporter for the UK Telegraph, with whose
permission this article is reprinted.



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