Is An Ice Age Coming?
By James Donahue
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."
