[pf] The latest 5-yearly report on Global Warming (to get final approval

[contains: 
  ".. if greenhouse emissions are not curtailed the earth's average surface
temperatures could be expected to increase between 2.7 to 11 degrees
Fahrenheit by the end of this century, substantially more than estimated in
its report five years ago: a range 1.8 to 6.3 degrees Fahrenheit. [This is
due] mainly to a reduced influence now expected to be played by sulfate
releases from industry and power plants."   D.]

http://dailynews.yahoo.com/h/ap/20001025/sc/global_warming_2.html
  is:

  Wednesday October 25 4:54 PM ET

  Pollution Adds To Global Warming 

  By H. JOSEF HEBERT, Associated Press Writer 

  WASHINGTON (AP) - New evidence shows man-made pollution has “contributed
substantially” to global warming and the earth is likely to get a lot
hotter than previously predicted, a United Nations-sponsored panel of
hundreds of scientists finds.

  The conclusions by the Intergovernmental Panel on Climate Change, the
most authoritative scientific voice on the issue, is expected to widely
influence climate debate over the next decade.

  The report's summary, a copy of which was obtained by The Associated
Press, was being distributed to government officials worldwide this week.

  It is the first full-scale review and update of the state of climate
science since 1995 when the same panel concluded there is “a discernible
human influence” on the earth's climate because of the so-called
“greenhouse” effect caused by the buildup of heat-trapping chemicals in the
atmosphere.

  Today, the panel says in its new assessment that “there is stronger
evidence” yet on the human influence on climate and that it is likely that
manmade greenhouse gases already “have contributed substantially to the
observed warming over the last 50 years.”

  And the scientists, in revised estimates, conclude that if greenhouse
emissions are not curtailed the earth's average surface temperatures could
be expected to increase from 2.7 to nearly 11 degrees Fahrenheit by the end
of this century, substantially more than estimated in its report five years
ago.

  It attributes the increase - from a range 1.8 to 6.3 degrees Fahrenheit
warmer in the 1995 assessment - mainly to a reduced influence now expected
to be played by sulfate releases from industry and power plants. Such
releases, which tend to have a cooling influence, will likely dramatically
decline in industrial countries because of other environmental concerns,
the scientists maintain.

  “What this report is clearly saying is that global warming is a real
problem and it is with us and we are going to have to take this into
account in our future planning,” said Kevin Trenberth, head of climate
analysis section at the National Center for Atmospheric Research.

  “It definitely reinforces what we were able to say in 1995,” added Tom
Wigley, a climate scientist at the center in Boulder, Colo. “It shows the
previous projects (in 1990 and 1995) were conservative.”

  Wigley, who did not participate in crafting the latest findings, was a
key author of the 1995 report's section about the human impact on climate.

  The IPCC's third assessment report is expected to get final approval at a
United Nations conference early next year. While some wording will
certainly be changed by government policy-makers, the central scientific
conclusions may not be altered, several scientists who have been involved
in the process, said Wednesday.

  Michael Oppenheimer, an atmospheric physicist at Environmental Defense,
said the latest assessment “reinforces the mainstream scientific consensus”
about global warming. Its new estimates of warming poses “a risk of
devastating consequences within this century.”

  Three years ago industrial nations tentatively agreed to curtail the
release of greenhouse gases - mainly carbon dioxide from burning fossil
fuels - to below 1990 levels as a first step to address global warming.

  But none of the major industrial countries has yet ratified the
agreement, crafted in Kyoto, Japan in 1997.
  Skeptics argue that the science has yet to be conclusive and that
computer models used to predict future climate is not reliable enough to
warrant a dramatic, and possibly very expensive, shift in energy use to
curtail carbon emissions into the atmosphere.

  The issue also has crept into the presidential campaign. Vice President
Al Gore has argued the science is clear and steps need to be taken soon to
begin reducing greenhouse emissions. His Republican rival, Gov. George W.
Bush, has not dismissed global warming, but urges a cautious approach and
believes the science still needs to be proven.

  The IPCC panel's summary of a voluminous technical report covering 14
chapters attempts to provide the most current state of scientific
understanding of the climate system and potential for future warming.

  While there are still uncertainties, the IPCC scientists say that there
is an “increasing body of observations” that provide a “collective picture
of a warming world” that cannot be solely explained by natural forces.

  “Emissions of greenhouse gases and aerosols due to human activities
continue to alter the atmosphere in ways that affect the climate system,”
the report says.

  Various findings of the last five years have reinforced the IPPC's 1995
determination that climate change warrants top-level attention by
government policy makers.

  Among the findings that suggest climate change already is underway,
according to the summary:

  - Warming over the last 100 years “is likely to be the largest of any
century during the past 1,000 years” when fully analyzed the 1990s are
likely to be the warmest decade with 1998 the warmest year of the 20th
century.

  - There has seen “a widespread retreat of mountain glaciers in nonpolar
regions” and a decline in sea-ice and snow-covered areas since over the
past 50 years.

  - Sea level rise has been 10 times greater in the last 100 years than the
average rate over the last 3,000 years. The oceans have become warmer over
the last 50 years.


  On the Net:

  National Center for Atmospheric Research: http://www.ncar.ucar.edu 

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sent on to Pos Fut by David.
(David MacClement) davd@ihug.co.nz 
http://www.geocities.com/davdd.geo/index.html#top
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