[lit-ideas] Re: global luke-warming
- From: Eric Yost <eyost1132@xxxxxxxxxxxxx>
- To: lit-ideas@xxxxxxxxxxxxx
- Date: Fri, 14 Apr 2006 19:29:23 -0400
The usual wackos have stepped up the propaganda
http://solar-center.stanford.edu/sun-on-earth/glob-warm.html
Some solar scientists are considering whether some
part of global warming may be caused, by a
periodic but small increase in the Sun's energy
output. An increase of just 0.2% in the solar
output could have the same affect as doubling the
carbon dioxide in the Earth's atmosphere.
LINKED TO
http://solar-center.stanford.edu/sun-on-earth/varsun.html
and
http://news.bbc.co.uk/1/hi/sci/tech/56456.stm
Climate changes such as global warming may be due
to changes in the sun rather than to the release
of greenhouse gases on Earth.
Climatologists and astronomers speaking at the
American Association for the Advancement of
Science meeting in Philadelphia say the present
warming may be unusual - but a mini ice age could
soon follow.
The sun provides all the energy that drives our
climate, but it is not the constant star it might
seem.
Careful studies over the last 20 years show that
its overall brightness and energy output increases
slightly as sunspot activity rises to the peak of
its 11-year cycle.
And individual cycles can be more or less active.
The sun is currently at its most active for 300
years.
WHICH IS CONTRADICTED BY THIS STUDY:
http://solar-center.stanford.edu/sun-on-earth/damon.html
Armchair detective work by University of Arizona
geosciences Professor Emeritus Paul Damon and a
colleague finds solar variation alone can explain
only 40 percent of the warming measured in the
20th century through 1975. It explains even less
of the heat spell of the last couple of decades.
''That rapid warming that occurred in the '80s and
'90s, there's no way to fit it,'' Damon said. By
default, then, he puts most of the culpability on
human input of greenhouse gases via cars,
factories and deforestation.
amon's analysis, undertaken with assistance from
Russian physicist Alexei Peristykh, attempts to
pinpoint the cause behind a clear signal of global
warming since about 1850. The observed temperature
increase roughly coincides with both the invention
of modern industry and a rise in solar activity.
However, the increase goes beyond what would be
expected from the sun's high-energy cycle, which
Damon projects will peak in 2030.
Damon and Peristykh compared a variety of data to
reach their conclusions. They used a well-known
link between global radiocarbon production and
solar activity to model sun cycles. Then they
compared this model to temperatures measured in
the last century or so as well as longer records
of climate, such as those estimated from
variations in tree-ring growth and changes in
oxygen isotopes in cores of ancient ice.
A 250,000-year ice core record compiled by
scientists working with Willy Dansgaard in Iceland
indicates longterm temperatures fluctuated widely
from glacial to interglacial periods, sometimes 9
degrees Fahrenheit at a time. But a few thousand
years after the Younger Dryas glaciers retreated
about 12,000 years ago, temperatures settled down,
never straying more than 1-degree Fahrenheit from
the global average.
''The important thing to remember is that global
temperatures have been stable for the past 8,000
years, so it doesn't take much solar forcing to
explain the record,'' Damon said.
Even when the Little Ice Age reached its coldest
point in the span from 1570 to 1730, average
global temperature appears to have cooled by no
more than 2 degrees Fahrenheit, he noted. However,
these relatively small temperature changes can
loom large in human perception, in part because
they fluctuate in certain regions much more than
the world as a whole.
This long reign of stable climate balanced near
the point of glaciation could end if predictions
on the overall warming effect of polluting the
atmosphere come to pass. International scientists
agree that global temperatures can be expected to
rise by about 2 to 8 degrees Fahrenheit by the end
of the next century, mainly due to the continuing
release of greenhouse gases.
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