Eric Gisin wrote:
Why are scientists still measuring temps in archaic units today?
Anyway, it important science. Wonder if alarmists will still denounce it.

You'll notice that the paper treats CO2 as a factor in GW as a foregone
conclusion. The question is where the heat is going. It surprises me
that the article doesn't mention the capacity of the oceans to absorb heat.

http://www.bnl.gov/bnlweb/pubaf/pr/P....asp?prID=1067

Why Hasn't Earth Warmed as Much as Expected?
New report on climate change explores the reasons
January 19, 2010

UPTON, NY - Planet Earth has warmed much less than expected during the
industrial era based on current best estimates of Earth's "climate
sensitivity"-the amount of global temperature increase expected in
response to a given rise in atmospheric concentrations of carbon dioxide
(CO2). In a study to be published in the Journal of Climate, a
publication of the American Meteorological Society (the early online
release of the paper is available starting 19 January 2010; the link is
given below), Stephen Schwartz, of Brookhaven National Laboratory, and
colleagues examine the reasons for this discrepancy.

According to current best estimates of climate sensitivity, the amount
of CO2 and other heat-trapping gases added to Earth's atmosphere since
humanity began burning fossil fuels on a significant scale during the
industrial period would be expected to result in a mean global
temperature rise of 3.8°F-well more than the 1.4°F increase that has
been observed for this time span. Schwartz's analysis attributes the
reasons for this discrepancy to a possible mix of two major factors: 1)
Earth's climate may be less sensitive to rising greenhouse gases than
currently assumed and/or 2) reflection of sunlight by haze particles in
the atmosphere may be offsetting some of the expected warming.

"Because of present uncertainties in climate sensitivity and the
enhanced reflectivity of haze particles," said Schwartz, "it is
impossible to accurately assign weights to the relative contributions of
these two factors. This has major implications for understanding of
Earth's climate and how the world will meet its future energy needs."

A third possible reason for the lower-than-expected increase of Earth's
temperature over the industrial period is the slow response of
temperature to the warming influence of heat-trapping gases. "This is
much like the lag time you experience when heating a pot of water on a
stove," said Schwartz. Based on calculations using measurements of the
increase in ocean heat content over the past fifty years, however, this
present study found the role of so-called thermal lag to be minor.

A key question facing policymakers is how much additional CO2 and other
heat-trapping gases can be introduced into the atmosphere, beyond what
is already present, without committing the planet to a dangerous level
of human interference with the climate system. Many scientists and
policymakers consider the threshold for such dangerous interference to
be an increase in global temperature of 3.6°F above the preindustrial
level, although no single threshold would encompass all effects.

The paper describes three scenarios: If Earth's climate sensitivity is
at the low end of current estimates as given by the Intergovernmental
Panel on Climate Change, then the total maximum future emissions of
heat-trapping gases so as not to exceed the 3.6° threshold would
correspond to about 35 years of present annual emissions of CO2 from
fossil-fuel combustion. A climate sensitivity at the present best
estimate would mean that no more heat-trapping gases can be added to the
atmosphere without committing the planet to exceeding the threshold. And
if the sensitivity is at the high end of current estimates, present
atmospheric concentrations of heat-trapping gases are such that the
planet is already committed to warming that substantially exceeds the
3.6° threshold.

The authors emphasize the need to quantify the influences of haze
particles to narrow the uncertainty in Earth's climate sensitivity. This
is much more difficult than quantifying the influences of the
heat-trapping gases. Coauthor Robert Charlson of the University of
Washington likens the focus on the heat trapping gases to "looking for
the lost key under the lamppost."

Schwartz observes that formulating energy policy with the present
uncertainty in climate sensitivity is like navigating a large ship in
perilous waters without charts. "We know we have to change the course of
this ship, and we know the direction of the change, but we don't know
how much we need to change the course or how soon we have to do it."

Schwartz and Charlson coauthored the paper with Ralph Kahn, NASA Goddard
Space Flight Center in Maryland; John Ogren, NOAA Earth System Research
Laboratory in Colorado; and Henning Rodhe, Stockholm University.

The early online release of the paper is available at AMS's journals
online site.

Founded in 1919, the AMS has a membership of more than 14,000
professionals, professors, students, and weather enthusiasts. AMS
publishes nine atmospheric and related oceanic and hydrologic journals,
sponsors multiple conferences annually, and directs numerous education
and outreach programs and services. For more information see
www.ametsoc.org.

Research at Brookhaven was funded by the U.S. Department of Energy
Office of Science.

Tags: environmental science
Number: 10-1067 | BNL Media & Communications Office