Scientists
in the U.K. have figured out how the Earth
recovered from a sudden episode of global
warming during the time of the dinosaurs. This
could help us understand how to survive the
upcoming climate change.
Global warming caused the erosion of rocks
to increase by 400%, leaching calcium and
magnesium into the ocean. This erosion could
have been caused by an increase in rainfall,
as well as higher ocean levels. These
chemicals combined with the carbon dioxide
that had been absorbed by the ocean, causing a
chemical reaction that led to falling levels
of greenhouse gases worldwide. Over a period
of about 150,000 years, the Earth returned to
normal.
Calcium combining with CO2 would have
created calcium carbonate, which does not
increase global warming. Researcher Anthony
Cohen says, "This intense rock- weathering
effectively put a brake on global warming
through chemical reactions that consumed the
atmosphere's extra carbon dioxide."
But how did the world heat up in the first
place? (Since dinosaurs didn't drive SUVs).
About 180 million years ago, temperatures on
Earth rapidly shot up, probably due to the
sudden release of huge amounts of methane from
the ocean floor. Methane is a greenhouse gas
which quickly changes to CO2, which stays in
the atmosphere for a long period of time,
absorbing sunlight and heating up the Earth.
But where did the methane come from?
Besides the vast amounts that are frozen deep
in the ocean floor, it may have also come from
the vast peat bogs in 200,000 miles of
Siberia. Climatologist Laurence Smith says,
"The bottom line is Siberian peat lands may be
a bigger player in climate change than we knew
before."
And what triggers the methane release?
Scientists at the University of Wyoming say
the ocean methane is released when water
temperatures rise. The methane in the ocean is
in a highly pressurized form and heat causes
faults in the ocean floor where it's stored to
break apart, releasing the gas. Matthew
Horbach says, "It's like a cork in a champagne
bottle. If you shake up the champagne and
build up enough pressure, the champagne
bubbles can pop the cork."
Smith says, "[This research] emphasizes a
point that has been emerging over the past few
years; the idea that the climate system is
highly unpredictable and full of thresholds
that can trigger greenhouse gas sources and
sinks to abruptly switch on and off. The more
of them we can identify, the more accurately
we can model and anticipate changes in the
future."
Cohen says, "What we have learned from
these rocks is how the Earth can, over a long
time, combat global warming. What we need to
discover now is why and at what point it goes
into combat mode, and precisely how long the
conflict takes to resolve."
