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Questão 29 de 30

Exercícios de Future

Listagem de exercícios

PUC-MG 2005

While global warming is being ignored by the political arm of the Bush administration, the citizens of Europe and the Pentagon are taking a new look at the greatest danger such climate change could produce for the northern hemisphere – a sudden change into a new ice age.

What they're finding is not at all comforting: if enough cold, fresh water coming from the melting polar ice caps and glaciers of Greenland and flowing into the northern Atlantic will shut down the Gulf Stream, which keeps Europe and northeastern North America warm. The worst case scenario would be a return of the last ice age in 2 to 3 years and the mid case scenario would be a period like the "little ice age" of a few centuries ago that disrupted worldwide weather patterns leading to extremely cold winters, desertification, crop failures and wars.

The warmth is the result of ocean currents that bring warm surface water up from the equator into northern regions that would otherwise be so cold that even in summer they'd be covered with ice. The current of greatest concern is called "The Great Conveyor Belt," which includes the Gulf Stream. It is driven by the greater force created by differences in water temperatures and salinity, as the North Atlantic Ocean is saltier and colder than the Pacific. If it stopped flowing today, the result would be sudden and dramatic. Winter would start in the eastern half of North America and all of Europe and Siberia, and never go away. Within three years, those regions would become uninhabitable and nearly two billion humans  would starve, freeze to death, or have to relocate.

And when might that happen? Nobody knows – the action of the Great Conveyor Belt in defining ice ages was discovered only in the last decade. Preliminary computer models and scientists suggest the change could happen as early as next year, or it may be generations from now. It may be starting right now, producing the extremes of weather we've seen in the past few years. What's almost certain is that if nothing is done about global warming, it will happen sooner rather than later.

SPEAK UP,ed. 206, jul. 2004 (adapted).

 

The word "will" conveys the idea of

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