[Vision2020] Geological Society of London Website Statement: PETM: Earth will take 100, 000 years to recover from global warming

[Ted Moffett]

It is always better, if possible, to read original sources on
scientific issues, than relying on news releases, that often
politicize, distort or oversimplify the science.  The statement at the
website below from the Geological Society of London contains numerous
scientific references as background to their analysis, and reveals
that a long process of review led to this final version, released this
month, November 2010:

http://www.geolsoc.org.uk/gsl/views/policy_statements/climatechange

I was a bit surprized to read the major focus on the PETM hyperthermal
from about 55 millions years ago by the Geological Society of London,
as a model of what impacts human CO2 emissions could cause, given just
last month I referenced the PETM in a Vision2020 post.  To anyone
studying climate science, the conclusions presented by the GSL are not
a major new revelation:

On Oct. 5, 2010, I wrote on Vision2020:

http://mailman.fsr.com/pipermail/vision2020/2010-October/071811.html

Regarding the preceding statement, to claim that because a snowball earth or
boiling oceans from CO2 levels much higher than they are now did not occur
in the past, that the idea of tipping points is a fantasy, is simply false.
If inducing sea level to rise dramatically, as has occurred in the past
linked to increased atmospheric CO2, involves a "tipping point," this is no
fantasy.  Consider the Paleocene-Eocene Thermal Maximum about 55 million
years ago, when CO2 levels were much higher, an Earth where there were
little or no polar ice caps, and ocean levels were far higher.   The
following scientific article from "Nature" (
http://es.ucsc.edu/~jzachos/pubs/Zachos_Dickens_Zeebe_08.pdf )states that
"During the most prominent and best studied hyperthermal, the
Paleocene-Eocene Thermal Maximum, ...the global temperature increased by
more than 5 C. in less than 10,000 years.  At about the same time, more than
2000 Gt C as CO2---comparable in magnitude to that which could occur over
the coming centuries---entered the atmosphere and oceans"
---------------------
A few excerpts from the statement from the Geological Society of
London on human impacts on climate are pasted in below, mentioning the
PETM:

http://www.geolsoc.org.uk/gsl/views/policy_statements/climatechange

"About 55 million years ago, at the end of the Paleocene, there was a
sudden warming event in which temperatures rose by about 6ºC globally
and by 10-20ºC at the poles22. Carbon isotopic data show that this
warming event (called by some the Paleocene-Eocene Thermal Maximum, or
PETM) was accompanied by a major release of 1500-2000 billion tonnes
or more of carbon into the ocean and atmosphere. This injection of
carbon may have come mainly from the breakdown of methane hydrates
beneath the deep sea floor10, perhaps triggered by volcanic activity
superimposed on an underlying gradual global warming trend that peaked
some 50 million years ago in the early Eocene. CO2 levels were already
high at the time, but the additional CO2 injected into the atmosphere
and ocean made the ocean even warmer, less well oxygenated and more
acidic, and was accompanied by the extinction of many species on the
deep sea floor. Similar sudden warming events are known from the more
distant past, for example at around 120 and 183 million years
ago23,24. In all of these events it took the Earth’s climate around
100,000 years or more to recover, showing that a CO2 release of such
magnitude may affect the Earth’s climate for that length of time25."
--------------------------

"In the coming centuries, continued emissions of carbon from burning
oil, gas and coal at close to or higher than today’s levels, and from
related human activities, could increase the total to close to the
amounts added during the 55 million year warming event – some 1500 to
2000 billion tonnes. Further contributions from ‘natural’ sources
(wetlands, tundra, methane hydrates, etc.) may come as the Earth
warms22. The geological evidence from the 55 million year event and
from earlier warming episodes suggests that such an addition is likely
to raise average global temperatures by at least 5-6ºC, and possibly
more, and that recovery of the Earth’s climate in the absence of any
mitigation measures could take 100,000 years or more. Numerical models
of the climate system support such an interpretation44. In the light
of the evidence presented here it is reasonable to conclude that
emitting further large amounts of CO2 into the atmosphere over time is
likely to be unwise, uncomfortable though that fact may be."

---------- Forwarded message ----------
From: Ted Moffett <starbliss at gmail.com>
Date: Fri, 5 Nov 2010 15:21:46 -0700
Subject: Geological Society in London: Earth will take 100,000 years
to recover from global warming
To: Moscow Vision 2020 <vision2020 at moscow.com>

http://www.telegraph.co.uk/earth/earthnews/8102821/Earth-will-take-100000-years-to-recover-from-global-warming-say-geologists.html
The
Earth will take 100,000 years to recover from global warming if mankind
continues to pump greenhouse gases into the atmosphere, geologists have
warned.

By Louise Gray <http://www.telegraph.co.uk/journalists/louise-gray/>,
Environment Correspondent
Published: 6:30AM GMT 02 Nov 2010

120 Comments<http://www.telegraph.co.uk/earth/earthnews/8102821/Earth-will-take-100000-years-to-recover-from-global-warming-say-geologists.html#disqus_thread>

A conference organised by the Geological Society in London this week will
bring together scientists from around the world to look at how the world
coped with climate change in the past.

By studying rock sediments from millions of years ago geologists have been
able to model how increases in greenhouse gases led to temperature change
and extinction of species.

Professor Jim Zachos, of the University of California, said that 55 million
years ago volcanic activity caused around 4,500 gigatons of greenhouse gases
to be released into the atmosphere over thousands of years.

This caused the planet to warm by 6C (10.8F), forcing whole ecosystems,
including early mammals, to adapt, migrate or die out in certain areas.

Prof Zachos said that if the world continues to pump out greenhouse gases at
the current rate, around 5,000 gigatons of greenhouse gases will be released
into the atmosphere over a few hundred years.

He said this will cause a more rapid temperature rise that at any other time
in history and could cause “mass extinction of species”.

“The impacts will be pretty severe compared to 55 million years ago in terms
of evolution of this planet,” he said.

The Geological Society warned that it could take the Earth 100,000 years to
recover.

A statement read: “The geological evidence from the 55 million year event
and from earlier warming episodes suggests that such an addition [a massive
increase in greenhouse gases caused by the activities of mankind] is likely
to raise average global temperatures by at least 5 to 6C, and possibly more,
and that recovery of the Earth’s climate in the absence of mitigation
measures could take 100,000 years or more. Numerical models of the climate
system support such an interpretation. In the light of the evidence
presented here it is reasonable to conclude that emitting further large
amounts of carbon dioxide into the atmosphere over time is likely to be
unwise, uncomfortable though that fact may be.”

------------------------------------------

Vision2020 Post: Ted Moffett