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Timely
warning
Can an
abrupt change in climate spell disaster? Raj Kaushik wonders what
lies in store the day after tomorrow
Known for his
blockbusters Independence Day (1996) and Godzilla (1998), Roland
Emmerich has once again surfaced with a new disaster drama, The Day
After Tomorrow. The $125-million movie is based on the theory of
“abrupt climate change”. It premiered on 28 May and has already
rocked the world with its controversial presentation of science.
“Oh my God, this is a disaster because it is such a distortion
of the science,” Harvard University paleoclimatologist Dan Schrag
described his first impression of the movie to the media. The film
portrays an abrupt shutdown of the Gulf Stream as a result of global
warming. The Gulf Stream is part of the Atlantic Thermohaline
Circulation (THC). The ocean is like a giant boiling tea pot where
hot water in the bottom becomes lighter, rises up and looses its
heat to the adjacent air on the surface. After losing its heat, the
surface water becomes cold and dense. The cold water then sinks down
and is replaced by the uprising hot water from the bottom.
Something similar to what happens in a boiling tea pot, the THC
transfers heat from the equator to the poles via surface ocean
currents. One of the most important surface ocean currents in the
world is the Gulf Stream, which surrenders its heat to the air
during its journey from the Gulf of Mexico up to the east coast of
North America.
By the time the water reaches Greenland, it
becomes so cold and dense that it sinks to depths between 2,000 and
3,000 meters and flows back south along the ocean bottom. The Gulf
Stream transports one billion megawatt of heat. Due to global
warming, glaciers will melt down, resulting into a huge amount of
fresh water diluting the salinity of oceanic water. As fresh water
is lighter than salty water, the diluted ocean water will not be
able to sink. That could potentially stop warm water from flowing
north, leading to a disruption in the THC.
The switching off of
the Gulf Stream in the movie leads to a severe storm, the likes of
which have never been seen, and a dramatic, overnight change in the
global climate. A super storm envelops the globe, flooding the
streets of New York City, sending tornadoes ripping through
Hollywood landmarks, pounding Tokyo with hail and burying New Delhi
in snow. The North Atlantic region starts to cool and plunges into a
new ice age while heat builds up in the tropics.
Nasa research
oceanographer William Patzert speaks for many scientists when he
says that the science presented in the movie is bad. According to
current scientific consensus, climate change might lead to a
weakening of the thermohaline circulation (THC), but it is not
expected to cause its complete halting. But not all scientists
dismiss the possibility of a rapid climate change event. Richard
Alley, Penn State University Glaciologist, studied a 3 kilometer
long ice core that was pulled from the centre of Greenland. The air
bubbles trapped deep inside the core reveal secrets about the
Earth’s atmosphere over a period of 100,000 years. Alley’s analysis
shows that at one point the global climate changed rapidly in as
little as 10 years.
Terrence Joyce, chairman of the Woods Hole
Department of Physical Oceanography, also believes that temperatures
may fall abruptly due to disruption in oceanic currents. “It could
happen in ten years. Once it does, it can take hundreds of years to
reverse,” Joyce tells Discover magazine. John Christy, a professor
and director of the Earth System Science Center at the University of
Alabama in Huntsville, has been looking for a global temperature
trend in huge amounts of information received from weather
satellites. Fortunately, Christy has found almost no sign of global
warming in the satellite data, and is confident that forecasts of
warming up to 10 degrees in the 21st century are wrong.
Madhav
Khandekar, who has edited the June 2003 issue of the International
Journal of Natural Hazards on extreme weather events, says that the
likelihood of increased incidences of extreme weather events in the
next 10 to 25 years is very small. Obviously, there’s a sharp
difference of opinion among scientists about global warming and the
time-frame of the risks it may pose. Scientists are influenced by
the way they collect and interpret data, but also by their broader
world views. Some scientists believe that climate change is already
happening now, not the day after tomorrow. A record heat wave
scorched Europe in August 2003, claiming an estimated 35,000 lives.
In France alone, 14,802 people died from the searing
temperatures.
In India, death tolls from heat that were recorded
over an entire summer some 10 years ago are now occurring in just
one week. Many scientists admit that the movie presents bad science
but still it’s a beautiful script in that it compels scientists to
start dialogue with the public and thus raises awareness about
climate change. Some environmental activists consider the movie as
an advantage to their cause. They hope the thought-provoking special
effects of the movie will spark debate about environmental
damage.
“I’m hoping more people will become more aware of this
problem and start thinking about what we can do to address it,” says
Janet Sawin, director of the energy and climate program at the
Worldwatch Institution in Washington. Former American Vice President
Al Gore also joins the chorus when he says the movie offers “a rare
opportunity to have a national conversation about what truly should
be seen as a global climate emergency.”
(A former project
coordinator with the National Council of Science Museums, India and
exhibits manager at the Discovery Centre, Halifax, the author now
works as senior server developer in Toronto.)
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