Skip to Content.
Sympa Menu

homestead - [Homestead] Creation, Loss of Climate Zones

homestead AT lists.ibiblio.org

Subject: Homestead mailing list

List archive

Chronological Thread  
  • From: sanrico AT highdesert.com
  • To: homestead AT lists.ibiblio.org
  • Subject: [Homestead] Creation, Loss of Climate Zones
  • Date: Thu, 29 Mar 2007 06:34:39 -0700 (PDT)

Morning, all -
I think, when I first joined the list, I asked if there were any thoughts on
how
'global warming' (at the time it was iffier than now, and deserving of quotes)
might affect agriculture and other home-steady issues...don't remember if
anyone
responded...
Has this article been submitted before?
Sandy

http://www.newswise.com/articles/view/528348/?sc=swtn

A new global warming study predicts that many current climate zones will
vanish
entirely by the year 2100, replaced by climates unknown in today's world.

Global climate models for the next century forecast the complete
disappearance of
several existing climates currently found in tropical highlands and regions
near
the poles, while large swaths of the tropics and subtropics may develop new
climates unlike anything seen today. Driven by worldwide greenhouse gas
emissions, the climate modeling study uses average summer and winter
temperatures
and precipitation levels to map the differences between climate zones today
and
in the year 2100 and anticipates large climate changes worldwide.

The work, by researchers at the University of Wisconsin-Madison and the
University of Wyoming, appears online in the Proceedings of the National
Academy
of Sciences during the week of March 26.

As world leaders and scientists push to develop sound strategies to understand
and cope with global changes, predictive studies like this one reveal both the
importance and difficulty of such a task. Primary author and UW-Madison
geographer Jack Williams likens today's environmental analysts to 15th-century
European mapmakers confronted with the New World, struggling to chart unknown
territory.

"We want to identify the regions of the world where climate change will
result in
climates unlike any today," Williams says. "These are the areas beyond our
map."

The most severely affected parts of the world span both heavily populated
regions, including the southeastern United States, southeastern Asia and
parts of
Africa, and known hotspots of biodiversity, such as the Amazonian rainforest
and
African and South American mountain ranges. The changes predicted by the new
study anticipate dramatic ecological shifts, with unknown but probably
extensive
effects on large segments of the Earth's population.

"All policy and management strategies are based on current conditions,"
Williams
says, adding that regions with the largest changes are where these strategies
and
models are most likely to fail. "How do you make predictions for these areas
of
the unknown?"

Using models that translate carbon dioxide emission levels into climate
change,
Williams and his colleagues foresee the appearance of novel climate zones on
up
to 39 percent of the world's land surface area by 2100, if current rates of
carbon dioxide and other greenhouse gas emissions continue. Under the same
conditions, the models predict the global disappearance of up to 48 percent of
current land climates. Even if emission rates slow due to mitigation
strategies,
the models predict both climate loss and formation, each on up to 20 percent
of
world land area.

The underlying effect is clear, Williams says, noting, "More carbon dioxide in
the air means more risk of entirely new climates or climates disappearing."

In general, the models show that existing climate zones will shift toward
higher
latitudes and higher elevations, squeezing out the climates at the extremes -
tropical mountaintops and the poles - and leaving room for unfamiliar climes
around the equator.

"This work helps highlight the significance of changes in the tropics,"
complementing the extensive attention already focused on the Arctic, says
co-author John Kutzbach, professor of atmospheric and oceanic sciences at
UW-Madison. "There has been so much emphasis on high latitudes because the
absolute temperature changes are larger."

However, Kutzbach explains, normal seasonal fluctuations in temperature and
rainfall are smaller in the tropics, and even "small absolute changes may be
large relative to normal variability."

The patterns of change foreshadow significant impacts on ecosystems and
conservation. "There is a close correspondence between disappearing climates
and
areas of biodiversity," says Williams, which could increase risk of
extinction in
the affected areas.

Physical restrictions on species may also amplify the effects of local climate
changes. The more relevant question, Williams says, becomes not just whether a
given climate still exists, but "will a species be able to keep up with its
climatic zone? Most species can't migrate around the world."

For the researchers, one of the most poignant aspects of the work is in what
it
doesn't tell them - the uncertainty. At this point, Williams says, "we don't
know
which bad things will happen or which good things will happen - we just don't
know. We are in for some ecological surprises."

The work was conducted in collaboration with Stephen Jackson at the
University of
Wyoming and was funded by the National Science Foundation.

___________________________________________
Get free email at http://www.highdesert.com




Archive powered by MHonArc 2.6.24.

Top of Page