Geography Reference
In-Depth Information
in the atmosphere and lead to a warming of the world's climate. Arrhenius was pretty smart—and about a
hundred years ahead of his time.
Scientists are now broadly agreed that the greenhouse effect is bringing about the greatest and most
rapid climate change in world history. It will have enormous consequences for life on earth. Since fossil
fuels began to be used on a massive scale with the onset of the Industrial Revolution, huge amounts of
carbon dioxide have been released, and this trend is now being aggravated by the burning of our tropical
forests. About four fifths of the carbon dioxide now comes from the burning of fossil fuels. The rest is
from destroying vegetation, mainly the felling of forests.
Why save the rain forests? Trees soak up carbon dioxide when alive, but release it when they are cut
down and burned.
The result is a steady warming of our planet. While there may be little change at the equator, the poles
may well become 7˚C warmer, with all the ultimate implications for the ice caps. As the polar ice caps
could eventually melt, sea levels might rise by five to seven meters (sixteen to twenty-two feet). Much of
the Netherlands would be flooded, together with half of Florida and huge sectors of other low-lying areas
such as Bengal, and many low-lying Pacific islands where the rise in sea levels will diminish freshwater
supplies even before flooding becomes a problem. Even a one-meter rise in the sea level could make 200
million people homeless.
But even this is likely to be overshadowed by the impact of global warming on harvests. While a warm-
er world might be able to grow more food overall, some nations will be winners and others losers. The
American Midwest, which helps to feed a hundred nations, may see its harvests cut by about a third. The
United States will still be able to feed itself, but exports to the rest of the world could fall by up to 70 per-
cent. New land will open up in Canada as the weather warms, but the soils are too poor to make up the loss.
The optimistic view is that Ukraine, once the breadbasket of the Soviet Union, may not be hit so badly,
and the land that opens up in Siberia is better than that in Canada. But there is a darker forecast that holds
that the ice concentrations under the frozen Siberian tundra would make the land useless for farming if it
defrosted. There is also some concern that methane, another dangerous greenhouse gas, is trapped in the
frozen tundra and might be released, with even more harmful results. A 2009 study, reported in the English
Daily Telegraph
, said the melting permafrost could trigger “unstoppable climate change” as the gases re-
leased would contribute further to the warming.
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Of course, poor countries will be hardest hit. Areas that
are already arid—like Tunisia, Algeria, Morocco, Ethiopia, Somalia, Botswana, eastern Brazil, and parts
of Asia—will probably dry out even further.
The 1980s were by far the hottest decade ever recorded. Seven out of the ten warmest years recorded
since 1880 occurred during this decade. And 1990 was ranked in several studies as the warmest year yet.
No one can be sure whether this is due to the greenhouse effect or whether it was simply the result of nat-
ural variability in the climate. A slight cooling took place in 1991, but that was attributed to the cloud of
dust thrown up by the eruption of Mount Pinatubo in the Philippines and would most likely be a temporary
situation slightly delaying an overall warming trend.
Geographic Voices
Elisabeth Rosenthal and Andrew Revkin,
New York Times
, February 3, 2007
In a grim and powerful assessment of the future of the planet, the leading international network
of climate scientists has concluded for the first time that global warming is “unequivocal” and that
human activity is the main driver, “very likely” causing most of the rise in temperatures since 1950.
Is All the Talk of Global Warming Just Hot Air?
