Re: [asa] NASA Administrator Michael Griffin Not Sure That Global Warming Is A Problem

From: Rich Blinne <>
Date: Fri Jun 01 2007 - 14:39:37 EDT

On Jun 1, 2007, at 11:36 AM, PvM wrote:

> The paper in question is well worth reading as it shows how science is
> doing the hard work and showing support for Gore's 'meme'
> My thanks to Janice for pointing us to this really interesting paper
> on global warming. No wonder the pope and recently GW seem to be
> jumping on the bandwagon since doing otherwise would be political, and
> scientific 'suicide'.

The press release below was approved by NASA prior to the statement
made by the administrator, so he cannot rightfully claim ignorance
about a changing climate is harmful. This is what Jim Hansen said on
May 25:

> It is noteworthy that the press release (attached) sailed through
> NASA Public Affairs, who, indeed, were very helpful. Note that it
> will not be released until after the holiday, on Tuesday May 29, so
> if it falls into the hands of media, they should observe an embargo
> on stories until 3 PM May 29.

                                 May 29, 2007
NASA Goddard Institute for Space Studies, New York



NEW YORK – NASA and Columbia University Earth Institute research
finds that human-made greenhouse gases have brought the Earth’s
climate close to critical tipping points, with [LO2][LO3]potentially
dangerous consequences for the planet.[LO4]

 From a combination of climate models, satellite data, and
paleoclimate records the scientists conclude that the West Antarctic
ice sheet, Arctic ice cover, and regions providing fresh water
sources and species habitat are under threat from continued global
warming. The research appears in the current issue of Atmospheric
Chemistry and Physics.

Tipping points can occur during climate change when the climate
reaches a state such that strong amplifying feedbacks are activated
by only moderate additional warming. This study finds that global
warming of 0.6ºC in the past 30 years has been driven mainly by
increasing greenhouse gases, and only moderate additional climate
forcing is likely to set in motion disintegration of the West
Antarctic ice sheet and Arctic sea ice. Amplifying feedbacks include
increased absorption of sunlight as melting exposes darker surfaces
and speedup of iceberg discharge as the warming ocean melts ice
shelves that otherwise inhibit ice flow.

The researchers used data on earlier warm periods in Earth’s history
to estimate climate impacts as a function of global temperature,
climate models to simulate global warming, and satellite data to
verify ongoing changes. Lead author James Hansen, NASA Goddard
Institute for Space Studies, New York, concludes: “If global
emissions of carbon dioxide continue to rise at the rate of the past
decade, this research shows that there will be disastrous effects,
including increasingly rapid sea level rise, increased frequency of
droughts and floods, and increased stress on [LO5]wildlife and plants
due to rapidly shifting climate zones.”

The researchers also investigate what would be needed to avert large
climate change, thus helping define practical implications of the
United Nations Framework Convention on Climate Change. That treaty,
signed in 1992 by the United States and almost all nations of the
world, has the goal to stabilize atmospheric greenhouse gases “at a
level that prevents dangerous human-made interference with the
climate system.”



Based on climate model studies and the history of the Earth the
authors conclude that additional global warming of about 1ºC (1.8ºF)
or more, above global temperature in 2000, is likely to be
dangerous. In turn, the temperature limit has implications for
atmospheric carbon dioxide (CO2), which has already increased from
the pre-industrial level of 280 parts per million (ppm) to 383 ppm
today and is rising by about 2 ppm per year. According to study co-
author Makiko Sato of Columbia’s Earth Institute, “the temperature
limit implies that CO2 exceeding 450 ppm is almost surely dangerous,
and the ceiling may be even lower.”

The study also shows that the reduction of non-carbon dioxide
forcings such as methane and black soot can offset some CO2 increase,
but only to a limited extent. Hansen notes that “we probably need a
full court press on both CO2 emission rates and non-CO2 forcings, to
avoid tipping points and save Arctic sea ice and the West Antarctic
ice sheet.”

A computer model developed by the Goddard Institute was used to
simulate climate from 1880 through today. The model included a more
comprehensive set of natural and human-made climate forcings than
previous studies, including changes in solar radiation, volcanic
particles, human-made greenhouse gases, fine particles such as soot,
the effect of the particles on clouds and land use. Extensive
evaluation of the model’s ability to simulate climate change is
contained in a companion paper to be published in Climate Dynamics.

The authors use the model for climate simulations of the 21st century
using both ‘business-as-usual’ growth of greenhouse gas emissions and
an ‘alternative scenario’ in which emissions decrease slowly in the
next few decades and then rapidly to achieve stabilization of
atmospheric CO2 amount by the end of the century. Climate changes
are so large with ‘business-as-usual’, with additional global warming
of 2-3ºC (3.6-5.4ºF) that Hansen concludes “‘business-as-usual’ would
be a guarantee of global and regional disasters.”

However, the study finds much less severe climate change – one-
quarter to one-third that of the "business-as-usual" scenario – when
greenhouse gas emissions follow the alternative scenario. “Climate
effects may still be substantial in the 'alternative scenario’, but
there is a better chance to adapt to the changes and find other ways
to further reduce the climate change,” said Sato.

While the researchers say it is still possible to achieve the
“alternative scenario,” they note that significant actions will be
required to do so. Emissions must begin to slow soon. “With another
decade of ‘business-as-usual’ it becomes impractical to achieve the
‘alternative scenario’ because of the energy infrastructure that
would be in place” says Hansen.

For more information about the NASA Goddard Institute for Space
Studies and the Columbia University Earth Institute visit:

  [LO1]"Near" is ambiguous. Atmospheric CO2 (383 ppm) is midway
between pre-industrial (280 ppm) and potentially "dangerous" (450)
levels. The issue is the accelerating rate of increase - the TIME at
which potentially "dangerous" levels will be reached.
  [LO2]Ambiguous meaning of "imminent" in the context of the press
release (time scales are well presented and discussed in the paper)
  [LO3]"tipping points" is not common usage and thus has ambiguous
definition. Wording change follows the paper's definition.
  [LO4]The Hansen et al. paper devotes much effort to defining/
interpreting the word "dangerous" in this context, and indeed often
encloses the word in quotes in the paper. The paper notes that there
is no single, quantitative threshold for "dangerous" climate
interference, but makes compelling cases for the significance of
predicted changes. Given the care which the paper takes in defining
the use of the word "dangerous" and the likely imprecision of most
readers' interpretation, care should be taken in the wording of the
press release to accurately reflect the thoughtful presentation of
the paper itself.
  [LO5]The paper does not discuss extinctions at all.

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Received on Fri Jun 1 14:39:58 2007

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