" Middle Ages were warmer than today, say scientists
By Robert Matthews, Science Correspondent
Claims that man-made pollution is causing "unprecedented" global
have been seriously undermined by new research which shows that the
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
than ever before, leading some scientists to conclude that greenhouse
from cars and power stations are causing these "record-breaking"
Last year, scientists working for the UK Climate Impacts Programme
that global temperatures were "the hottest since records began" and
"We are pretty sure that climate change due to human activity is here
This announcement followed research published in 1998, when scientists
the Climatic Research Unit at the University of East Anglia declared
the 1990s had been hotter than any other period for 1,000 years.
Such claims have now been sharply contradicted by the most
study yet of global temperature over the past 1,000 years. A review of
than 240 scientific studies has shown that today's temperatures are
the warmest over the past millennium, nor are they producing the most
extreme weather - in stark contrast to the claims of the
The review, carried out by a team from Harvard University, examined
findings of studies of so-called "temperature proxies" such as tree
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
higher even than today.
They also confirm claims that a Little Ice Age set in around 1300,
which the world cooled dramatically. Since 1900, the world has begun
up again - but has still to reach the balmy temperatures of the Middle
The timing of the end of the Little Ice Age is especially significant,
it implies that the records used by climate scientists date from a
the Earth was relatively cold, thereby exaggerating the significance
today's temperature rise.
According to the researchers, the evidence confirms suspicions that
"unprecedented" temperatures are simply the result of examining
change over too short a period of time.
The study, about to be published in the journal Energy and
been welcomed by sceptics of global warming, who say it puts the
environmentalists in proper context. Until now, suggestions that the
Ages were as warm as the 21st century had been largely anecdotal and
often challenged by believers in man-made global warming.
Dr Philip Stott, the professor emeritus of bio-geography at the
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
Medieval Warm Period, the world was warmer even than today, and
shows that it was a wonderful period of plenty for everyone."
In contrast, said Prof Stott, severe famines and economic collapse
the onset of the Little Ice Age around 1300. He said: "When the
started to drop, harvests failed and England's vine industry died. It
one wonder why there is so much fear of warmth."
The United Nation's Intergovernmental Panel on Climate Change (IPCC),
official voice of global warming research, has conceded the
today's "record-breaking" temperatures may be at least partly caused
Earth recovering from a relatively cold period in recent history.
evidence for entirely natural changes in the Earth's temperature
to grow, its causes still remain mysterious.
Dr Simon Brown, the climate extremes research manager at the
Office at Bracknell, said that the present consensus among scientists
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
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
proxies such as tree rings: "They are not able to capture the recent
of the last 50 years," he said. "