Small group of US experts insist global warming not man-made
Date: Sunday, December 16, 2007 @ 16:31:40 MST
A small group of US experts stubbornly insist that, contrary to what
the vast majority of their colleagues believe, humans may not be
responsible for the warming of the planet Earth.
These experts believe that global warming is a natural phenomenon, and they point to reams of data they say supports their assertions.
These conclusions are in sharp contradiction to those of the United Nations Intergovernmental Panel on Climate Change (IPCC), which reached its conclusions using largely similar data.
The UN body of about 3,000 experts, including several renown US
scientists, jointly won the award with former US vice president Al Gore
for their work to raise awareness about the disastrous consequences of
In mid-November the IPCC adopted a landmark report stating that the
evidence of a human role in the warming of the planet was now
Retreating glaciers and loss of snow in Alpine regions, thinning
Arctic summer sea ice and thawing permafrost shows that climate change
is already on the march, the report said.
Carbon pollution, emitted especially by the burning of oil, gas and
coal, traps heat from the Sun, thus warming the Earth's surface and
inflicting changes to weather systems.
A group of US scientists however disagree, and have written an
article on their views that is published in The International Journal
of Climatology, a publication of Britain's Royal Meteorological
"The observed pattern of
warming, comparing surface and atmospheric temperature trends, doesn't
show the characteristic fingerprint associated with greenhouse
warming," wrote lead author David Douglas, a climate expert from the
University of Rochester, in New York state.
"The inescapable conclusion is that human contribution is not
significant and that observed increases in carbon dioxide and other
greenhouse gases make only a negligible contribution to climate
warming," Douglas wrote.
According to co-author John Christi from the University of Alabama,
satellite data "and independent balloon data agree that the atmospheric
warming trends do not exceed those of the surface," while greenhouse
models "demand that atmospheric trend values be two to three times
Data from satellite observations "suggest that greenhouse models
ignore negative feedback produced by clouds and by water vapor, that
diminish the warming effects" of human carbon dioxide emissions.
The journal authors "have good reason, therefore, to believe that
current climate models greatly overestimate the effects of greenhouse
For Fred Singer, a climatologist at the University of Virginia and
another co-author, the current warming "trend is simply part of a
natural cycle of climate warming and cooling that has been seen in ice
cores, deep sea sediments and stalagmites . . . and published in
hundreds of papers in peer reviewed journals."
How these cyclical climate take place is still unknown, but they
"are most likely caused by variations in the solar wind and associated
magnetic fields that affect the flux of cosmic rays incident on
cloudiness, and thereby control the amount of sunlight reaching the
earth's surface and thus the climate."
Singer said at a recent National Press Club meeting in Washington
that there is still no definite proof that humans can produce climate
The available data is ambiguous, Singer said: global temperatures,
for example, rose between 1900 and 1940, well before humans began to
burn the enormous quantities of hydrocarbons they do today. Then they
dropped between 1940 and 1975, when the use of oil and coal increased,
Singer believes that other factors -- like variations of solar
winds and terrestrial magnetic field that impact cloud formations and
the amount of sunlight reaching the Earth's surface, and thus
determining the temperature -- are much more influential than
human-generated greenhouse gas emissions.
© 2007 AFP