Michaels: Global climate will
not change markedly
should be listening to nature talking ... [and] not rush
policy decisions before we have strong and clear evidence
that our projections are sound.
By Fariss Samarrai
global warming scenarios envision temperatures rising over the
next 100 years to the point that plants will produce less and
seas will rise dramatically, swamping coastal cities.
scenarios suggest only slight global temperature increases with
coastal zones remaining high and dry and plant production actually
less dramatic one, the one that looks more like the same
world as today, is right, says Virginia
State Climatologist Patrick Michaels. He has published a paper
in a recent issue of the journal Climate Research that calls into
question the high end of the temperature ranges projected by the
United Nations Intergovernmental Panel on Climate Change,
of which Michaels is a member.
rate of warming will not be much different than it was over the
last 30 years, said Michaels, a professor of environmental
sciences at U.Va.
most climate models produce a constant rate of future warming,
that rate varies dramatically. Michaels research was designed
to determine which of these rates are more likely than others.
uses nature itself as his model, comparing past real temperature
rates to those predicted in computer models.
has been integrating the response to greenhouse effect changes
for nearly a half-century, while models have been producing diverse
projections, Michaels said.
years ago the IPCC produced its third assessment report, which
indicated a global rise in temperatures of 1.4 to 5.8 degrees
Celsius for 1990 to 2100.
Michaels new independent study indicates the most likely
value is around 1.6 degrees Celsius, near the low end of the IPCC
range. He used an assortment of data to produce a range of possible
temperatures for the period, and all were substantially less broad
than the IPCCs range.
one scenario, he used data from recent studies that closely examine
the assumptions made about climate behavior in the U.N. report
and found a range of warming of 1.1 to 2.8 degrees Celsius.
using data of actual climate change rates during the past 25 years
of greenhouse warming, and projecting it out to the year 2100,
he found a range of 1.5 to 2.6 degrees Celsius.
all models produce a constant rate of warming, Michaels
said. So why not let nature choose that rate?
he factored both aspects of his study together, he found a range
of 1.0-1.6 degrees Celsius.
by adjusting the averages of a range of climate models to reflect
actual observed changes in temperature in nature, he found a warming
range of 1.3-3.0 degrees Celsius, with a central value of 1.9
consistency of these somewhat independent results encourages us
to conclude that 21st century warming will be modest and near
the low end of the IPCCs third assessment report projections,
says that much of the data in the panels report is based
on older, less accurate studies that take into account neither
what has actually occurred in nature during the past century nor
the more refined and accurate independent findings of more recent
paper looks at what should have been examined in the IPCC report,
he said. We should be listening to nature talking.
also said society is producing more fuel-efficient machinery and
will continue to do so throughout this century, further reducing
the likelihood of dramatic warming.
is why we shouldnt rush policy decisions before we have
strong and clear evidence that our projections are sound,
Michaels said. In this study we demonstrate that the IPCCs
evidence for intense warming projections is weak, but the evidence
for the low end of their range is very strong.
full article can be accessed at: http://www.int-res.com/articles/cr2003/23/c023p001.pdf