The notion that global warming represents a threat of impending
doom is commonly portrayed as indisputable fact, one entirely
beyond discussion.
We are told, as in Al Gore’s film “An Inconvenient
Truth,” that the warming trend may kill countless numbers of
people living in coastal regions as melting glaciers raise the sea
level.
Extreme weather events, like Hurricane Katrina, are touted as
examples of the catastrophic results of global warming.
This view is spread by representatives of environmental
organizations on our campus, such as Tim Webber, canvasser for the
national environmentalist organization Greenpeace.
“The weather is getting more severe. I normally talk about
Hurricane Katrina as a classic example of this,” Webber told
me.
This sensationalism, often coupled with a call for drastic
action, ends up hurting the debate on global warming. Many of the
commonly reported claims of this type are highly disputed or
contradicted by the same widely accepted reports that are said to
support the notion of global warming.
The 2007 study being released this Friday by the United Nations
Intergovernmental Panel on Climate Change ““ considered the
authority on global warming ““ does not predict a catastrophic
rise in the sea level over the next century, but rather a rise
between 5 and 23 inches.
In an interview for Essential Science Indicators, the aptly
named Christopher Landsea of the National Oceanic and Atmospheric
Administration’s Hurricane Research Division, there is no
evidence that storms are becoming more volatile as a result of
global warming.
Both of these revelations, made by key global warming
scientists, contradict the picture of disaster painted by
environmentalists and sympathetic journalists.
The greenhouse effect, where atmospheric gases trap the
sun’s energy, is itself largely uncontroversial, as is the
recent trend of increased temperatures (a rise of 1 degree in the
last century, according to the IPCC report).
The source of the controversy is the extent to which humans are
responsible for this climate change.
According to the IPCC, there is only evidence that the earth is
warmer than at any other time in the last six centuries, which it
touts as proof that humans are responsible for recent climate
change.
But proponents of the view that humans have caused this change
must show that recent temperature changes result from an increase
in emissions and are a departure from any natural trend.
Given that the time frame for natural climate variations is in
the hundreds of thousands of years, this evidence is entirely
unpersuasive.
Graphs from a National Academy of Sciences report that depict
temperature change in the latter time frame suggest that the recent
temperature change and increase in the concentration of carbon
dioxide is part of a long-run natural cycle. The same report calls
for action on impending climate change.
There are other inconsistencies. One of the two major periods of
temperature increase in the 20th century occurred between 1910 and
1945. This warming cannot be explained by greenhouse gases, which
increased only slightly during the period.
The IPCC report explains this by noting that solar radiation
“may have contributed in an important manner to the warming
in the 20th century, particularly in the period from 1900 to
1950.”
So the global warming advocates explain roughly half of the 20th
century’s 1-degree rise by factors other than global warming
when the data doesn’t match their predictions. And since the
period from 1940 through the 1970s was a period of global cooling,
proponents are left with only the last three decades as evidence
for the theory that global warming is man-made.
One would think that, say, snow in Los Angeles would be an
argument against a warming trend.
The IPCC reports that there is no evidence that weather events
are becoming more extreme. To the contrary, the study finds that
over the past few decades, there has been a “decrease in
spatial and temporal variability of temperatures.”
But global-warming alarmists have managed to convince us,
contrary to the evidence, that whatever happens ““ warming or
cooling ““ is evidence of the phenomenon’s far-reaching
effects.
If we’re going to be taking costly steps in the name of
curbing humanity’s contribution to global warming, we better
be sure that the temperature change is a man-made departure from
any natural cycles. There ought to be conclusive evidence that
global warming’s effects are disastrous, or at least greatly
undesirable.
And I’m not convinced.
If you’re afraid of change, e-mail Lazar at
dlazar@media.ucla.edu for some reassuring words. Send general
comments to viewpoint@media.ucla.edu.