The temperature is as likely to go down as up.
By Richard Lindzen, Sunday Telegraph.
No,
global warming isn't a real threat, says Richard Lindzen, Arthur P Sloan
Professor of Meteorology at the Massachusetts Institute of Technology
Over
the last 100 years or so, globally averaged surface temperature, which
is always varying a little, has gone both up and down, but over the
whole period it is estimated to have risen about half a degree
centigrade (using the US National Climate Data Centre's analysis; other
analyses give as much as 0.65C).
However,
this value is associated with substantial error bars, and the warming is
occurring in a system that can vary about that much without any forcing
at all - something not surprising in a system that is both turbulent and
heterogeneous.
Yes,
there does appear to be warming, but the amount is hardly certain or
indisputable. And the amount found does not appear that alarming.
The
alarm, I would suppose, comes from the notoriously inadequate climate
models.
As
the primary "consensus" document, the Scientific Assessment of
the UN's Intergovernmental Panel on Climate Change notes, modellers at
the United Kingdom's Hadley Centre had to cancel two-thirds of the model
warming in order to simulate the observed warming.
So
the warming alarm is based on models that overestimate the observed
warming by a factor of three or more, and have to cancel most of the
warming in order to match observations.
Rather
than entertaining the rather obvious possibility that the models are
over-reacting to increasing greenhouse gases, advocates are assuming
that the cancellation will disappear in the future. Why might models be
over-reacting?
The
answer is actually fairly simple. Carbon dioxide and methane are minor
greenhouse gases (and methane has, for unknown reasons stopped
increasing, during the last five years). Doubling carbon dioxide in the
atmosphere would, all else held constant, only lead to about 1C of
warming; quadrupling carbon dioxide would only add another 1C (there is
a diminishing return in warming per unit carbon dioxide).
The
greater response arises because in current models, the most important
greenhouse substances, water vapour and clouds, act so as to amplify the
impact of increasing carbon dioxide. But, as the previously cited IPCC
document notes, water vapour and especially clouds are major sources of
uncertainty in models.
Given
the above, what is all the hyperventilating about? Personally, I don't
know. It certainly can't be the temperature record. For the past five
years, the global mean temperature has been flat to within a few
hundredths of a degree (well within the measurement uncertainty);
indeed, there has been no statistically significant change in 10 years.
Perhaps,
on the other hand, that is the reason. Individuals across the planet
have been pushing their agenda to "hurry the future" for over
20 years. Maybe, they feel that if they can't get their way now, they
may never be able to. After all, like hurricane frequency or the price
of oil, global mean temperature is as likely to go down as up.
However,
the more obvious question is why is the agenda specified (typically such
things as pollution reduction, energy independence, efficiency,
north-south transfer of wealth and technology, etc.) in need of the
artificial support of global warming hysteria?
Many
of those goals could be more easily achieved (assuming they are
reasonable goals) if we ceased to focus on carbon dioxide, which is a
natural and essential substance produced by breathing. With trillions of
dollars at stake, this is no small matter.
To
be sure, for those who enthuse over the regulatory state, the
possibility of regulating breathing must be like a dream come true.
Under
the circumstances, perhaps we should be suspicious of the dishonourable
tradition of establishing the alleged truth of global warming by
constant repetition, while ignoring reality.
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