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TIME: Almanac 1990s
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1993-04-15
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<text id=93TT0267>
<link 93TO0113>
<title>
July 26, 1993: If You Think The Weather Is Bad...
</title>
<history>
TIME--The Weekly Newsmagazine--1993
July 26, 1993 The Flood Of '93
</history>
<article>
<source>Time Magazine</source>
<hdr>
COVER, Page 33
DISASTERS
If You Think The Weather Is Bad...
</hdr>
<body>
<p> Weather is almost impossible to predict more than a week or
two in advance. But when it comes to climate--the long-term
weather averages that make the U.S. temperate and the tropics
torrid--scientists are confident that they understand the
overall pattern. Over the past million years or so, the planet
has swung between ice ages lasting on the order of 100,000 years
and interglacial periods of about 10,000. During each phase,
the climate is pretty steady. It's the stability of the current
interglacial epoch, which began 10,000 years ago, that made
the invention of agriculture, and thus the rise of civilization,
possible.
</p>
<p> Now it looks as though the concept of long-term stability may
be wrong. According to two articles in last week's Nature, deep
holes drilled into the ancient ice of Greenland have brought
up evidence of sudden, dramatic swings in climate during the
last interglacial period, about 120,000 years ago. Several times,
average global temperatures dropped as much as 25 degreesF,
plunging the planet back into ice-age conditions, and stayed
there for tens or hundreds of years before recovering. And the
changes happened not over centuries, as scientists would have
predicted, but in as little as a decade. The tranquillity of
recent centuries may be a climatic fluke.
</p>
<p> The discovery, says British scientist David Peel, co-author
of one of the reports, is "staggering." Worldwide temperature
shifts of a few degrees over half a century--the kind envisioned
in theories of global warming--would disrupt weather patterns,
change sea levels and be difficult for animal and plant life
to adjust to. The changes Peel measured, though, are roughly
three times as severe and rapid.
</p>
<p> One ominous sign: normal temperatures during the last interglacial
epoch were about 4 degreesF warmer than they are this time around,
and levels of carbon dioxide in the atmosphere were significantly
higher. As humans pump more and more CO2 into the air and temperatures
rise, the planet will approach the state it was in back then.
And if those conditions tend to be inherently unstable--an
idea scientists consider plausible--people may someday look
back on the early 1990s as an idyllic time when the weather
was benign.
</p>
<p> By Michael D. Lemonick. Reported by Barry Hillenbrand/London
</p>
</body>
</article>
</text>