Rapid climate change
From
Bizzare Science comes this link to a story in
Physics Today:
bq. How fast can our planet's climate change? Too slowly for humans to notice, according to the firm belief of most scientists through much of the 20th century. Any shift of weather patterns, even the Dust Bowl droughts that devastated the Great Plains in the 1930s, was seen as a temporary local excursion. To be sure, the entire world climate could change radically: The ice ages proved that. But common sense held that such transformations could only creep in over tens of thousands of years.
bq. During the early 1970s, most climate experts came to agree that interglacial periods tended to end more abruptly than had been supposed. Many concluded that the current warm period could end in a rapid cooling, possibly even within the next few hundred years. Bryson, Stephen Schneider, and a few others took this new concern to the public. They insisted that the climate we had experienced in the past century or so, mild and equable, was not the only sort of climate the planet knew. For all anyone could say, the next decade might start a plunge into a cataclysmic freeze, drought, or other change unprecedented in recent memory, although not without precedent in the archaeological and geological record.
That's right - 35 years ago, the enviros were screaming their heads off about the upcoming ice age and how human activity was sure to be causing it...
bq. The 2001 report of the Intergovernmental Panel on Climate Change, pronouncing the official consensus of the world's governments and their climate experts, reported that a shutdown in the coming century was "unlikely" but "cannot be ruled out." If such a shutdown did occur, it would change climates all around the North Atlantic--a dangerous cooling brought on by global warming.
bq. Now that the ice had been broken, so to speak, most experts were prepared to consider that rapid climate change--huge and global change--could come at any time. "The abrupt changes of the past are not fully explained yet," wrote the NAS committee in its 2002 report, "and climate models typically underestimate the size, speed, and extent of those changes. Hence, ... climate surprises are to be expected."1 Despite the profound implications of this new viewpoint, hardly anyone rose to dispute it.
and more:
bq. The actual history shows that even the best scientific data are never that definitive. People can see only what they find believable. Over the decades, many scientists who looked at tree rings, varves, ice layers, and such had held evidence of decade-scale climate shifts before their eyes. They easily dismissed it. There were plausible reasons to dismiss global calamity as nothing but a crackpot fantasy. Sometimes the scientists' assumptions were actually built into their procedures: When pollen specialists routinely analyzed their clay cores in 10-cm slices, they could not possibly see changes that took place within a centimeter's worth of layers. If the conventional beliefs had been the same in 1993 as in 1953--that significant climate change always takes many thousands of years--the short-term fluctuations in ice cores would have been passed over as meaningless noise.
Climate is a complex issue and there is a lot that we do not know. One thing we do know is that we are leaving a cool period and heading towards a period of warming.
The key thing is that this warming is not in any way a result of the activity of humans on this planet. The warming started well before we kicked out significant amounts of CO2 and the current warming trend follows several cycles of warming and cooling that have been well documented from Medieval times.
Global warming as defined by the Kyoto protocols is junk science and needs to be nipped in the bud.
Posted by DaveH at January 9, 2004 1:18 PM