Killer 'triple burp' of methane caused massive global warming (Forwarded)

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Dr. Anthony S. Cohen, +44 (0) 1908 858360

EMBARGO 18:00 hours BST, 14 September 2005

PR5062

Killer 'triple burp' of methane caused massive global warming

Open University researchers have uncovered startling new evidence about
an extreme period of a sudden, fatal dose of global warming some 180
million years ago during the time of the dinosaurs. The scientists'
findings could provide vital clues about climate change happening today
and in the future.

The OU Department of Earth Sciences team, PhD student Dave Kemp and
supervisors Drs. Angela Coe and Anthony Cohen, along with Dr. Lorenz
Schwark of the University of Cologne, discovered evidence suggesting
that vast amounts of methane gas were released to the atmosphere in
three massive 'methane burps' or pulses. The addition of methane, a
greenhouse gas, to the atmosphere had a severe impact on the
environment, warming Earth about 10 C, and resulting in the extinction
of a large number of species on land and in the oceans.

Dr Angela Coe says: "We've known about this event for a few years
through earlier work by our team and others, but there's been a great
deal of uncertainty about its precise size, duration, and underlying
cause. What our present study shows is that this methane release was
not just one event, but 3 consecutive pulses. Importantly, our data
demonstrate that each individual pulse was very rapid. Also, whilst the
methane release was very quick, we've found that the recovery took much
longer, occurring over a few hundred thousand years".

The methane came from gas hydrate, a frozen mixture of water and methane
found in huge quantities on the seabed. This hydrate suddenly melted,
allowing the methane to escape. The OU researchers based their findings
on geochemical analyses of mudrocks that are preserved along the
Yorkshire coast near Whitby, UK, and date from the Jurassic Period of
geological time.

Dave Kemp, whose PhD is funded by the Natural Environment Research
Council (NERC), says: "The methane was released because slight wobbles
in the Earth's orbit periodically bring our planet closer to the Sun,
warming the oceans sufficiently to melt the vast reserves of hydrate. We
believe that this effect was compounded by warming from greenhouse gases
from volcanoes. After the methane was released into the atmosphere from
the seabed it reacted rapidly with oxygen to form carbon dioxide. Carbon
dioxide is also a powerful greenhouse gas that persists in the
atmosphere for many hundreds of years, and it was this gas which caused
such a massive global warming effect".

Dr Anthony Cohen adds: "One of the most important aspects of the study
is that it provides an accurate timescale for how the Earth, and life,
reacted to a sudden increase in atmospheric carbon dioxide. Today we
are releasing large amounts of carbon dioxide to the atmosphere,
primarily through the burning of fossil fuels. It is possible that the
rate at which carbon dioxide is being added to the atmosphere now
actually outstrips the rate at which it was added 180 million years ago.
Given that the effects were so devastating then, it is extremely
important to understand the details of past events in order to better
comprehend present-day climate change. With this information, we are
better informed about what action needs to be taken to mitigate or avoid
some of the potential detrimental future effects".

Editor's Notes

The research done by The Open University scientists is published in full
by Nature magazine on 15 September 2005.

Resources

Website:
http://cepsar.open.ac.uk/index.htm
http://www.nature.com/index.html
http://www.nerc.ac.uk/