From: Spudboy100@aol.com
Date: Mon Apr 07 2003 - 10:31:04 MDT
http://news.telegraph.co.uk/news/main.jhtml?xml=/news/2003/04/06/nclim06.xml&
sSheet=/news/2003/04/06/ixhome.html/news/2003/04/06/nclim06.xml
Middle Ages were warmer than today, say scientists
By Robert Matthews, Science Correspondent
(Filed: 06/04/2003)
Claims that man-made pollution is causing "unprecedented" global warming have
been seriously undermined by new research which shows that the Earth was
warmer during the Middle Ages.
From the outset of the global warming debate in the late 1980s,
environmentalists have said that temperatures are rising higher and faster
than ever before, leading some scientists to conclude that greenhouse gases
from cars and power stations are causing these "record-breaking" global
temperatures.
Last year, scientists working for the UK Climate Impacts Programme said that
global temperatures were "the hottest since records began" and added: "We are
pretty sure that climate change due to human activity is here and it's
accelerating."
This announcement followed research published in 1998, when scientists at the
Climatic Research Unit at the University of East Anglia declared that the
1990s had been hotter than any other period for 1,000 years.
Such claims have now been sharply contradicted by the most comprehensive
study yet of global temperature over the past 1,000 years. A review of more
than 240 scientific studies has shown that today's temperatures are neither
the warmest over the past millennium, nor are they producing the most extreme
weather - in stark contrast to the claims of the environmentalists.
The review, carried out by a team from Harvard University, examined the
findings of studies of so-called "temperature proxies" such as tree rings,
ice cores and historical accounts which allow scientists to estimate
temperatures prevailing at sites around the world.
The findings prove that the world experienced a Medieval Warm Period between
the ninth and 14th centuries with global temperatures significantly higher
even than today.
They also confirm claims that a Little Ice Age set in around 1300, during
which the world cooled dramatically. Since 1900, the world has begun to warm
up again - but has still to reach the balmy temperatures of the Middle Ages.
The timing of the end of the Little Ice Age is especially significant, as it
implies that the records used by climate scientists date from a time when the
Earth was relatively cold, thereby exaggerating the significance of today's
temperature rise.
According to the researchers, the evidence confirms suspicions that today's
"unprecedented" temperatures are simply the result of examining temperature
change over too short a period of time.
The study, about to be published in the journal Energy and Environment, has
been welcomed by sceptics of global warming, who say it puts the claims of
environmentalists in proper context. Until now, suggestions that the Middle
Ages were as warm as the 21st century had been largely anecdotal and were
often challenged by believers in man-made global warming.
Dr Philip Stott, the professor emeritus of bio-geography at the University of
London, told The Telegraph: "What has been forgotten in all the discussion
about global warming is a proper sense of history."
According to Prof Stott, the evidence also undermines doom-laden predictions
about the effect of higher global temperatures. "During the Medieval Warm
Period, the world was warmer even than today, and history shows that it was a
wonderful period of plenty for everyone."
In contrast, said Prof Stott, severe famines and economic collapse followed
the onset of the Little Ice Age around 1300. He said: "When the temperature
started to drop, harvests failed and England's vine industry died. It makes
one wonder why there is so much fear of warmth."
The United Nation's Intergovernmental Panel on Climate Change (IPCC), the
official voice of global warming research, has conceded the possibility that
today's "record-breaking" temperatures may be at least partly caused by the
Earth recovering from a relatively cold period in recent history. While the
evidence for entirely natural changes in the Earth's temperature continues to
grow, its causes still remain mysterious.
Dr Simon Brown, the climate extremes research manager at the Meteorological
Office at Bracknell, said that the present consensus among scientists on the
IPCC was that the Medieval Warm Period could not be used to judge the
significance of existing warming.
Dr Brown said: "The conclusion that 20th century warming is not unusual
relies on the assertion that the Medieval Warm Period was a global
phenomenon. This is not the conclusion of IPCC."
He added that there were also doubts about the reliability of temperature
proxies such as tree rings: "They are not able to capture the recent warming
of the last 50 years," he said.
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