Is An Ice Age Coming?
One of the world's great unsolved mysteries has been the question
of what happened to the dinosaurs. That the remains of these
creatures, together with saber-toothed tigers, wooly mammoths and
other extinct warm climate animals were found perfectly preserved
in the permanent frost of the northern tundra across North
America and Asia, only compounds the puzzle.
The animals were found with their meals, vegetation including
flowers and grass, still in their mouths and undigested. This
means that they were literally quick-frozen in their tracks. The
catastrophic event that brought on their demise and altered the
world about 14,000 years ago, happened very fast.
That event probably brought on our most recent ice age.
Geologists believe the Earth has experienced numerous ice ages
during its long history. The cause of these dynamic climate
changes has always been part of the mystery.
A few years ago, radio personalities Art Bell and Whitley
Strieber co-authored a book called The Coming Global Superstorm,
in which they offered an interesting theory.
They said scientific evidence suggests that before the last ice
age started, there was a gradual buildup of methane gas in the
atmosphere, which slowly caused the planet to heat. When the
planet reached a certain temperature, there was a sudden release
of a massive amount of methane from the oceans and the land,
which caused a dramatic temperature spike.
Bell and Strieber predict continued heating, fires and general
flooding of the planet as the ice melts. Interestingly enough,
they note that one of the signs of the end will be a slowing
down, or alteration in direction of the natural ocean currents
that tend to keep world climates stable.
Geology professors Howard Spero of UC Davis and David Lea of UC
Santa Barbara have a report of a new study appearing in this
month's issue of Science, that supports Bell and Strieber's
belief that shifts on ocean circulation are involved in climate
changes.
In their article, titled, "The Cause of Carbon Isotope Minimum
Events on Glacial Terminations," Spero and Lea link global
warming to shifts on deep ocean currents.
"An understanding of the relative timing of this event is
critical because the greenhouse gases that humans are producing
are likely to affect not only the warming of the atmosphere but
also the circulation of the oceans," Spero said in a story
released by University Of California - Davis. "Changes in
atmospheric temperature can have immense effects on the flow of
the deep ocean currents, which in turn can affect weather and
climate worldwide."
Terrence Joyce, senior scientist at the prestigious Woods Hole
Oceanographic Institution in Massachusetts, recently developed a
theory that links this gaseous heating of the planet to the onset
of a possible ice age.
In his article that appeared in the New York Times, titled "The
Heat Before the Cold," Joyce writes: "
paradoxically, global
warming could actually bring colder temperatures to some highly
populated areas like Eastern North America and Western Europe."
Joyce said there has been a gradual buildup of fresh water in the
North Atlantic, caused by the melting Arctic ice, which is
lowering the salt content of the ocean. This, in turn, threatens
to slow or turn the ocean current of warm water that flows from
the tropics northward along the East Coast of the United States
before turning toward Europe.
If the current gets turned, Joyce warns that winters in the
Northeast and Europe will get much colder. He said a study of
tree rings and ice cores suggests that this is what happened just
before the last ice age. The effect lasted about 1,000 years.
A similar study by University of Bern researchers Thomas Stocker
and Andreas Schmittner, published in Nature Magazine in 1997,
comes up with the same conclusions found by Joyce.
The Stocker-Schmittner study determined that the Atlantic Gulf
Stream transports a billion megawatts of heat from the Gulf of
Mexico northward along the East American Coastline and then to
Europe.
The report concludes that "the consequences of a shut-down in the
Atlantic Ocean thermohaline circulation are uncertain." However,
it reports that paleoclimatological evidence suggests that
similar disruptions have happened before.
A story in Natural Science said: "Deep ocean sediments dating
from the last Ice Age suggest that the fresh water run-off from
melting ice masses decreased sea water density sufficiently to
cause a breakdown of ocean overturning. What followed was a
European winter 10 degrees Celsius below normal and cold spells
that lasted for hundreds of years."
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