WASHINGTON - The Earth will become a much hotter
place over the next century, according to researchers who
predict in a study published on Friday there is a 90 percent
chance the planet's average temperatures will rise 3 to 9
degrees Fahrenheit by 2100.
Researchers at the National Center for Atmospheric Research
in Boulder, Colorado, used a computer model to predict probable
long-term increases in the Earth's temperature if no actions
are taken to curb the emissions of gases and pollutants that
many scientists blame for global warming.
The researchers said the planet has warmed up by about 1
degrees over the last century. But they say it is likely to
heat up by about 1 or 2 degrees as early as 2030.
Members of a US Greenpeace delegation protest against the role of the United States at the international climate protection conference in Bonn, July 19, 2001. Environment ministers fought to salvage the Kyoto accord despite the unbending position of the United States, the world's biggest polluter, to the 1997 pact against global warming. (Michael Dalder/Reuters)
By 2100, the most likely increase would be in the range of
4 to 7 degrees, while there is a 90 percent chance global
average temperatures will rise 3 to 9 degrees, they said.
Tom Wigley, the lead researcher, said a broad range of
possible long-term temperature changes does little to assist
policy makers. For example, an estimated global warming range
of 2.5 to 10.4 degrees was announced this year by the
Intergovernmental Panel on Climate Change (IPCC), established
in 1988 by the U.N. World Meteorological Organization and U.N.
Wigley said the new study aimed to tell policy makers what
level of global warming is most likely.
World leaders have been at loggerheads over what steps
governments need to take to reduce emissions -- especially
after the United States withdrew in March from the 1997 Kyoto
Protocol, a global deal to cut pollution.
He said the computer model sought to account for various
uncertainties that could impact warming.
``There are two that absolutely dominate,'' Wigley, whose
study appears in the journal Science, said in an interview.
``One is human beings, and uncertainties in things like
population and economic growth and technological development
and awareness of environmental issues. Those human and
socioeconomic uncertainties essentially produce a very wide
range of possible emissions for the gases that might cause
changes in climate in the future,'' he added.
The other primary uncertainty factor, Wigley added, is just
how sensitive the Earth's climate system is to man-made
Some critics say there is scant evidence of a man-made
cause of global warming.
New estimates of sulfur dioxide and other emissions, along
with updated information on carbon storage, ocean circulation,
radiation, and other components of the Earth system have
improved computer climate models, the researchers said.
Even aggressive action to curb so-called greenhouse
emissions and other factors that may contribute to global
warming may be too late prevent continued temperature rises,
``The climate system is like a giant flywheel. Even if we do
a lot of things in the near future to try to reduce emissions
or reduce the growth of emissions, then the system has a lot of
inertia and it is going to keep warming for a long, long time,''
``So already in place are a lot of unavoidable climate
change consequences no matter what we do. But that doesn't mean
we should give up. And there are a lot of things we can do. And
what we have to do is balance the economic cost against the
In a commentary in Science, experts at the Massachusetts
Institute of Technology and the University of North Carolina
note the difficulty in making such temperature predictions.
``Future emissions of greenhouse gases, their climatic
effects and the resulting environmental and economic
consequences are subject to large uncertainties,'' said the
experts, led by MIT's John Reilly.
Many scientists believe emissions of certain pollutants
from industry, power plants, vehicles and other sources
threaten to disrupt global climate and ecosystems by causing
the Earth's atmosphere to trap more of the sun's energy,
triggering global warming.
Copyright © 2001 Reuters Limited.