Re: Cirrus Disappearance, Warming Thins Heat-trapping Clouds
- From: "alanmc95210@xxxxxxxxx" <alanmc95210@xxxxxxxxx>
- Date: Sun, 11 Nov 2007 08:06:59 -0800
On Nov 8, 6:22 am, dogtop <rainbowrockfoundat...@xxxxxxxxxxxxxx>
wrote:
On Nov 8, 4:51 pm, "Bonzo" <boo...@xxxxxxxxxxxxxx> wrote:
ScienceDaily
Nov. 5, 2007
http://www.sciencedaily.com/releases/2007/11/071102152636.htm
The widely accepted (albeit unproven) theory that manmade global warming
will accelerate itself by creating more heat-trapping clouds is
challenged this month in new research from The University of Alabama in
Huntsville.
Instead of creating more clouds, individual tropical warming cycles that
served as proxies for global warming saw a decrease in the coverage of
heat-trapping cirrus clouds, says Dr. Roy Spencer, a principal research
scientist in UAHuntsville's Earth System Science Center.
That was not what he expected to find.
"All leading climate models forecast that as the atmosphere warms there
should be an increase in high altitude cirrus clouds, which would
amplify any warming caused by manmade greenhouse gases," he said. "That
amplification is a positive feedback. What we found in month-to-month
fluctuations of the tropical climate system was a strongly negative
feedback. As the tropical atmosphere warms, cirrus clouds decrease. That
allows more infrared heat to escape from the atmosphere to outer space."
"While low clouds have a predominantly cooling effect due to their
shading of sunlight, most cirrus clouds have a net warming effect on the
Earth," Spencer said. With high altitude ice clouds their infrared heat
trapping exceeds their solar shading effect.
In the tropics most cirrus-type clouds flow out of the upper reaches of
thunderstorm clouds. As the Earth's surface warms - due to either
manmade greenhouse gases or natural fluctuations in the climate system -
more water evaporates from the surface. Since more evaporation leads to
more precipitation, most climate researchers expected increased cirrus
cloudiness to follow warming.
"To give an idea of how strong this enhanced cooling mechanism is, if it
was operating on global warming, it would reduce estimates of future
warming by over 75 percent," Spencer said. "The big question that no one
can answer right now is whether this enhanced cooling mechanism applies
to global warming."
The only way to see how these new findings impact global warming
forecasts is to include them in computerized climate models.
"The role of clouds in global warming is widely agreed to be pretty
uncertain," Spencer said. "Right now, all climate models predict that
clouds will amplify warming. I'm betting that if the climate models'
'clouds' were made to behave the way we see these clouds behave in
nature, it would substantially reduce the amount of climate change the
models predict for the coming decades."
The UAHuntsville research team used 30- to 60-day tropical temperature
fluctuations - known as "intraseasonal oscillations" - as proxies for
global warming.
"Fifteen years ago, when we first started monitoring global temperatures
with satellites, we noticed these big temperature fluctuations in the
tropics," Spencer said. "What amounts to a decade of global warming
routinely occurs in just a few weeks in the tropical atmosphere. Then,
as if by flipping a switch, the rapid warming is replaced by strong
cooling. It now looks like the change in cirrus cloud coverage is the
major reason for this switch from warming to cooling."
The team analyzed six years of data from four instruments aboard three
NASA and NOAA satellites. The researchers tracked precipitation amounts,
air and sea surface temperatures, high and low altitude cloud cover,
reflected sunlight, and infrared energy escaping out to space.
When they tracked the daily evolution of a composite of fifteen of the
strongest intraseasonal oscillations they found that although rainfall
and air temperatures would be rising, the amount of infrared energy
being trapped by the cloudy areas would start to decrease rapidly as the
air warmed. This unexpected behavior was traced to the decrease in
cirrus cloud cover.
The new results raise questions about some current theories regarding
precipitation, clouds and the efficiency with which weather systems
convert water vapor into rainfall. These are significant issues in the
global warming debate.
"Global warming theory says warming will generally be accompanied by
more rainfall," Spencer said. "Everyone just assumed that more rainfall
means more high altitude clouds. That would be your first guess and,
since we didn't have any data to suggest otherwise ..."
There are significant gaps in the scientific understanding of
precipitation systems and their interactions with the climate, he said.
"At least 80 percent of the Earth's natural greenhouse effect is due to
water vapor and clouds, and those are largely under the control of
precipitation systems.
"Until we understand how precipitation systems change with warming, I
don't believe we can know how much of our current warming is manmade.
Without that knowledge, we can't predict future climate change with any
degree of certainty."
Spencer and his colleagues expect these new findings to be
controversial.
"I know some climate modelers will say that these results are
interesting but that they probably don't apply to long-term global
warming," he said. "But this represents a fundamental natural cooling
process in the atmosphere. Let's see if climate models can get this part
right before we rely on their long term projections."
The results of this research were published recently in the American
Geophysical Union's "Geophysical Research Letters" on-line edition. The
paper was co-authored by UAHuntsville's Dr. John R. Christy and Dr. W.
Danny Braswell, and Dr. Justin Hnilo of Lawrence Livermore National
Laboratory, Livermore, CA.
Adapted from materials provided by University Of Alabama In Huntsville.
--
Get The Facts At
http://www.junkscience.com/Greenhouse/index.html
Excellent Links At
http://www.warwickhughes.com/
Regards
Bonzo
"If the atmosphere was a 100 story building, our annual anthropogenic
CO2
contribution today would be equivalent to the linoleum on the first
floor"
D'Aleo
"...and I think future generations are not going to blame us for
anything except for being silly, for letting a few tenths of a degree
panic us"
Dr. Richard Lindzen, Professor of Meteorology MIT and Member of the
National Academy of Sciences
"What most commentators-and many scientists-seem to miss is that the
only thing we can say with certainly about climate is that it changes"
Dr. Richard Lindzen
[most of the current alarm over climate change is based on] "inherently
untrustworthy climate models, similar to those that cannot accurately
forecast the weather a week from now." Dr. Richard Lindzen
Chemistry 101 Closed systems strive for equilibriem There will always
be survivers in some form? BUT will it be human or beast? Lets all
hope we can evolve that fast and it is a little of everthing!- Hide quoted text -
- Show quoted text -
Homo Erectus was able to spread from tropical Africa to throughout
Eurasia, THEY were smart enough to adapt to different climate
conditons; I suspect Homo Sapiens may be at least as intelligent and
adaptable as Homo Erectus- A. McIntire
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