Sweden's Royal Academy of Sciences named American scientist Wallace S. Broecker as the 2006 prizewinner in geosciences.
In spite of the UN scientists who say they have arrived at a "consensus" (a/k/a have agreed on their best guesses based MAINLY upon their computer models), Dr. Broecker says that climate scientists have greatly underestimated the complexity of the earth's climate system and that it is next to impossible to come up with reliable models to work with because there are too many IMPORTANT unknown variables and that complicates predictions of the consequences of the ongoing buildup of greenhouse gases in the atmosphere.
Here he is excerpted:
"My lifetime study of Earth's climate system has humbled me. I'm convinced that we have greatly underestimated the complexity of this system. The importance of obscure phenomena, ranging from those that control the size of raindrops to those that control the amount of water pouring into the deep sea from the shelves of the Antarctic continent, makes reliable modeling very difficult, if not impossible. ... The climate record kept in ice and in sediment reveals that since the invention of agriculture some 8000 yr ago, climate has remained remarkably stable. By contrast, during the preceding 100,000 yr, climate underwent frequent, very large, and often extremely abrupt shifts. Furthermore, these shifts occurred in lockstep across the globe. They seem to be telling us that Earth's climate system has several distinct and quite different modes of operation and that it can jump from one of these modes to another in a matter of a decade or two. So far, we know of only one element of the climate system which has multiple modes of operation: the oceans' thermohaline circulation. ...Perhaps the mode shifts revealed in the climate record were initiated in the sea.
This discovery complicates predictions of the consequences of the ongoing buildup of greenhouse gases in the atmosphere.
....cold water is fed in from the thermoclines to the North and South Pacific. The now famous El Niño cycle involves a turning on and off of this upwelling. This cycle has a strong impact on today's global climate. So I think that somehow the change in the vigor of upper-ocean circulation must have altered the strength of upwelling into the equatorial region and, in turn, the delivery of water vapor into the atmosphere. .... In fact, the models are powerless to produce the large global changes that the paleorecords prove to have taken place. Why water vapor?, you might ask.
The answer is that water vapor is the atmosphere's most powerful greenhouse gas. If you wanted to cool the planet by 5°C and could magically alter the water-vapor content of the atmosphere, a 30% decrease would do the job. In fact, the major debate among atmospheric scientists regarding the magnitude of the coming greenhouse warming hinges on what's referred to as the water-vapor feedback. If the water vapor in the atmosphere were to remain exactly the same as it is now, then a doubling of CO2 would heat the planet only about 1.2°C. ...So the question naturally arises, What is the probability that through adding CO2 we will cause the climate system to jump to one of its alternate modes of operation? ...we can't yet reproduce any of these jumps in computer simulations, we don't really know how many modes of operations Earth has...Our climate system has proven that it can do very strange things. Since we've only recently become aware of this capability, there's nothing concrete that we can say about the implications. This discovery certainly gives us even more reason to be prudent about what we do, though. ..We must think all this through. .." ~ Wallace S. Broecker 05/97 http://www.geosociety.org/pubs/gsatoday/gsat9705.htm
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