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The Scientific Argument against the Paris Climate Agreement

Patrick J. Michaels

Last May, Donald Trump vowed to “cancel the Paris climate
agreement.” It was a scripted remark in a prepared text, an
unusual speech for the then-presidential candidate.

Since then, he has reportedly been under pressure from his
daughter Ivanka — who has set up an intensive review process
on climate change policy — along with her husband Jared
Kushner and Secretary of State Rex Tillerson to remain in the deal.
But Ivanka’s left-leaning tendencies have likely colored her
choice of scientists allowed into the discussions.

All of this ignores a heretofore unrecognized fact: The Paris
Agreement is based upon a fundamental misconception of climate
history and science. The objective is to hold temperatures to
“well below” 2 degrees Celsius above preindustrial
levels, and to “pursue efforts” to limit the increase
to 1.5 degrees Celsius.

The Paris Agreement is
based upon a fundamental misconception of climate history and
science.

The key misconception is that all of the warming since the
Industrial Revolution — 0.9 degrees Celsius — is a
result of human activity.

Hardly. Since the beginning of reliable global temperature
records in the late 19th century, there have been two periods of
significant warming that are statistically indistinguishable in
magnitude. The first period ran from 1910 through about 1945, with
a temperature increase of around 0.5 degrees Celsius. There could
only be minimal human influence on this period, simply because
humans had not emitted very much carbon dioxide.

After a slight cooling, the second one began sometime around
1976 and ended with the big 1998 El Nino. This period was likely in
part due to a greenhouse effect.

The reason this period was affected by greenhouse warming is
because the lower stratosphere cooled at the same time, which is a
prediction of greenhouse theory. If, as some people maintain,
“it’s all the sun,” then the whole atmosphere
would warm.

Interestingly, when the lower atmospheric warming paused after
1998, the stratosphere also stopped cooling. What’s happening
now is quite unclear as surface temperatures are constantly being
readjusted.

So, after allowing for a small bit of other influence on the
second warming, we’re left with the notion that the maximum
warming caused by humans is somewhere between 0.4 and 0.5 degrees
Celsius — half of the total since the Industrial
Revolution.

This has huge implications. If, as the Paris Agreement
erroneously assumes, all of the warming of 0.9 degrees is a result
of human activity, there is no way that the aspirational goal of
1.5 degrees can ever be met. Thanks to the huge thermal inertia of
the ocean, current models show there’s between 0.4 degrees
and 0.6 degrees of warming on the way, even if emissions were capped at
2000 levels.

That’s a total of 1.5 degrees already guaranteed. Meeting
the 2 degrees objective allows only an additional half of a degree
in wiggle room. The Paris Agreement only mitigates about 0.2
degrees of warming. Again, believing in those models, that would be
an additional warming of over 2 degrees Celsius this century.

So according to the United Nation’s own climate models, it
is scientifically impossible. President Trump, that’s grounds
enough to withdraw.

On top of that, the models that form the basis of the Paris
Agreement are predicting way too much warming in the lower
atmosphere, and erroneously predicting a dramatic warming of the
upper atmosphere over the tropics. Most precipitation on earth is a
result of the temperature difference between the lower layers and
what’s aloft.

Get that wrong, which the climate models do systematically, and
the models are of very little utility.

There are other, more reality-based approaches to estimating
future warming, and these point to a 21st century increase of
closer to 1.4 degrees Celsius. Adding that to the maximum human
contribution to-date of 0.5 degrees yields 1.9 degrees, meeting the
Paris objective without the Paris Agreement.

President Trump, that’s also grounds enough to
withdraw.

Patrick J.
Michaels
is director of the Center for the Study of Science at
the Cato Institute.