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- THE WEEK, Page 19HEALTH & SCIENCEBrrr! What Global Warming?
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- The eruption of Mount Pinatubo is cooling the planet off --
- temporarily
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- What harm man can do, nature can undo -- at least for a
- while. While the alumni of the Rio environment conference
- undertake complex schemes to combat global warming, scientists
- are finding that Mother Nature is quietly applying her own highly
- efficient methods.
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- Since the Industrial Revolution, gases like carbon dioxide
- and methane have been wafting into the atmosphere, where they
- let the sun's rays in to warm the earth but keep excess heat
- from escaping back into space. Acting like the glass walls of
- a greenhouse, these gases have forced the planet's temperature
- up 0.8 degreesC (1.5 degreesF) over the past century or so. If
- the trend continues, temperatures could increase up to 5
- degreesC (9 degreesF) within 50 years, raising the sea level,
- distorting weather patterns and causing widespread environmental
- disruption.
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- But now the ecological disaster known as global warming
- has been put off five years at least, thanks to last year's
- eruption of Mount Pinatubo. When the Philippine volcano blew its
- top, it lofted some 20 million tons of sulfur dioxide into the
- upper atmosphere. Since then, the stuff has circled the globe,
- forming a layer of droplets floating in the stratosphere,
- between 19 and 23 km (12 and 14 miles) above the surface.
- Scientists predicted that the droplets would act as a worldwide
- sun shield. Satellite measurements are proving they were right:
- the planet has cooled off about 0.5 degreesC (1 degreesF) since
- Pinatubo, erasing nearly a century's worth of rising
- temperatures. Unfortunately, the fallout will disappear in three
- to five years. After that, global warming should resume, as
- menacingly as ever.
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