[Vision2020] August 15, 2011 Spokesman-Review: Study Fixes Humans’ Role "...melting of the ice pack is... actual change in climate."

[Ted Moffett]

Spokesman-Review article from today mentioned in subject heading pasted in
at bottom.

As is well known to students of climate science, and often ignored by those
with an agenda to dismantle the credibility of modern climate science, the
primary data for climate predictions regarding future impacts from human
influences is Earth's paleoclimate history, not results from computer
models.  Computer models are merely tools that must predict the paleoclimate
data if they are to be regarded as reliable to make predictions for the
future.  Consider this recent research from the Goddard Institute for Space
Studies to elucidate my point:
http://www.giss.nasa.gov/research/briefs/hansen_15/
 Earth's Climate History: Implications for Tomorrow

By James E. Hansen and Makiko Sato — July 2011

Contrary to popular belief, climate models are not the principal basis for
assessing human-made climate effects. Our most precise knowledge comes from
Earth's paleoclimate, its ancient climate, and how it responded to past
changes of climate forcings, including atmospheric composition. Our second
essential source of information is provided by global observations today,
especially satellite observations. which reveal how the climate system is
responding to rapid human-made changes of atmospheric composition,
especially atmospheric carbon dioxide (CO2). Models help us interpret past
and present climate changes, and, in so far as they succeed in simulating
past changes, they provide a tool to help evaluate the impacts of
alternative policies that affect climate.
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The comments above from GISS scientists are consistent with the methods used
by the scientists who just published the
following paper in Geophysical Research Letters, discussed in the Spokesman
Review today, “Interannual to multidecadal Arctic sea ice extent trends in a
warming world.”

They ran the computer model with 4000 years worth of climate history data to
determine how well the model predicted empirical facts of Earth's past
climate.

For some reason, every time I've tried to access the AGU website below to
read the abstract for this paper, the website shut down generating an error
message; but the website was clearly providing information on this exact
paper under discussion.  However, this AGU website offers a brief discussion
of the paper: http://www.agu.org/news/press/pr_archives/2011/2011-27.shtml

http://m.spokesman.com/stories/2011/aug/15/study-of-ice-melt-fixes-humans-role/

http://www.agu.org/pubs/crossref/2011/2011GL048008.shtml
 Study of ice melt fixes humans’ role

*Richard Mauer* McClatchy

August 15, 2011

ANCHORAGE, Alaska – About half the recent record loss of Arctic sea ice can
be blamed on global warming caused by human activity, according to a new
study by scientists from the nation’s leading climate research center.

The peer-reviewed study, funded by the National Science Foundation, is the
first to attribute a specific proportion of the ice melt to greenhouse gases
and particulates from pollution.

The study used supercomputers and one of the world’s most sophisticated
climate models to reach its conclusions, said lead author Jennifer Kay, a
staff scientist at the National Center for Atmospheric Research in Boulder,
Colo. The paper was published last week in the scientific journal
Geophysical Research Letters.

Kay said her study was an attempt to learn how much Arctic Ocean melting can
be attributed to “natural variability” – complex changes wrought by nonhuman
forces – and how much has been caused by greenhouse gases such as carbon
dioxide and by atmospheric particulates.

In doing so, she was also able to look ahead to future annual and
decade-long fluctuations. She and the other authors said conditions will
become more volatile from year to year. That means there will be years and
perhaps decades when the ice pack expands. But the trend is in the
other direction.

“There’s no doubt about it: sea ice is going away,” she said. “What we found
was that about half of that trend is related to the increasing greenhouse
gases.” The other half of the sea-ice loss, as observed over the late 20th
century, was “just related to variability in the system.”

The study comes at an important time as public policy and climate change
intersect in Alaska and elsewhere in the North. The reduction of the ice
pack is already opening Arctic waters to transportation, development and
military activities. The NCAR study says that the melting of the ice pack is
no short-term fluke but an actual change in climate.

In the study, the authors said earlier research determined that greenhouse
gases were responsible for some loss of sea ice, but no one had been able to
firmly establish how big a part they played.

Kay said the climate model she chose, Community Climate System Model version
4, had been developed by teams of scientists over several decades. She ran
4,000 years’ worth of data through the model, a period when volcanoes, solar
variations and other factors were known or believed to have caused
climate changes.

The scientists placed extra focus on the years since 1979, when satellite
images became available to determine the extent of sea-ice depletion.

The model accurately “predicted” what actually occurred historically,
validating the method, she said.

But more to the point, by replaying the climate forces of the 20th century
over and over through the model, the scientists were able to show that
variability can account for only half the loss of ice, she said.

That means that if humans were still only hunters and gatherers, sea ice
might have retreated anyway over the past 30 years.
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Vision2020 Post: Ted Moffett
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