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Global Warming Studies Improve
yoink! writes: "The BBC news service is running a story which indicates that previous global warming predictions failed to take the oceans and their temperatures into consideration. Those involved with the studies, according to the article, articulate our [homo sapiens'] important role in helping to warm earth's climate. This could very well add fuel to the debate between natural, polution independant, warming cycles and humanity's destruction of our only home."
This document seems to suggest that the trend observed over the past 50 years, is a change from the previous 4 billion years. To use 50 years of data in such a way is irrational and irresponsible. To quote another: In the space of one hundred and seventy-six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oölitic Siluian Period, just a million years ago next November, the Lower Mississippi River was upward of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesome returns of conjecture out of such a trifling investment of fact.
The fact is we need to learn more about is going on and how the earth and its weather works. It only makes sense to move on what we believe is going on. The earth is getting warmer but is this really wrong, or bad or even having anything to do with us? If we correct the weather only because we do not like it is that also bad. But as long as people are able to be convinced that the earth is only 5,000 years old by religious crack heads. What luck do we have in getting someone to agree on changing there life style go stop something that is less understood and provable than the age of the earth?
Even some oil companies are -- however grudingly -- starting to admit that it looks like (a) there's something going on and that (b) we're at least part of the cause. But the rest, of course, cling desperately to anything that can keep the denial alive ... at least until after they quietly sell off their beachfront properties.
(And in the background, one can hear the flocks of sheep bah-bah-ing as they graze on the astroturf.)
From NYTimes: "Using two different computer simulations of climate and the oceans, separate research teams have concluded that a buildup of heat in the seas over the last five decades was almost certainly caused by the heat- trapping effect of greenhouse gases released into the air by human activities." http://www.nytimes.com/2001/04/13/science/13CLIM.h tml
Are you spontaneously enthusiastic about everyone having everything you can have? - Buckminster Fuller
Before anyone rushes to accept or reject the current arguments about climate change, ask whether there is any evidence of the Earth climate's ever having changed in the past. The answer is yes -- global and regional climates have changed enormously over hundreds and thousands of years. Some well-documented examples are:
Scroogle
All that the results prove is that these simulations agree with the expectations of those running them (I can't use the word "scientists" here). There's an indication that they are not simulating the real world.
And other things keep getting discovered, like the cirrus iris effect where local heating causes cooling.
Simply because the world's seawater stores millions of times more heat than the atmosphere, and the warm sea currents from tropical oceans transport some of this heat to northern continents like the USA and Europe which would otherwise be permanently freezing cold due to their northerly latitude. Warm sea currents are vital to agriculture and our continued well-being.
Yes, the warm sea currents that keep the planet warm have an Achilles heel -- sea currents stop moving if the saltiness of the seawater falls below a critical level (the density of seawater depends on its saltiness, reduced-salt seawater won't sink as it normally does in the coldest polar regions, and without sinking seawater the ocean currents stop moving).
One of the agreed effects of increasing Carbon Dioxide emissions is that rainfall will increase in northern latitudes, diluting the seawater. In the limit dilution shuts down the warm sea currents.
The Gulf Stream is the most important warm sea current because it can alter worldwide climate by various positive feedback mechanisms. The climate and food production of the USA and Europe, for example, both depend on the Gulf Stream keeping the climate warm enough to grow crops.
The Gulf Stream is known to be sensitive to changes in rainfall over the Atlantic. Rahmstorf's bifurcation model of Atlantic thermohaline circulation is widely accepted by independent scientists. This model implies the Atlantic Ocean has only two stable modes of circulation -- ON and OFF. The Atlantic Ocean is currently in the ON mode with an active Gulf Stream. 100000 years ago, it went into the OFF mode when the Gulf Stream shut down causing a worldwide massive Ice Age. The model shows the likely cause of the shutdown was increased rainfall.
The Gulf Stream changes slightly in intensity from year to year, but overall its average state in recent decades is stable and active. However, the situation should be monitored closely because it is unknown exactly how much additional rainfall the Gulf Stream can tolerate without shutting down. The Rahmstorf model predicts a critical threshold of about 1Sv/yr (10^6m/yr) (sustained increase) which is ~50% above current long-term average rainfall, whereas rainfall over Northern Europe has actually been increasing only by about 2% a year over the last 20 years -- a total rise of 40% which is currently below the 50% threshold. Conclusion: the Gulf Stream looks safe now but vulnerable to future rainfall increases.
Most agricultural plants probably wouldn't survive. The summer air temperature in the US Mid-West, for example, would be just 32F(0C) which would stop all agricultural production.
The ORNL has researched the types of vegetation in the US in present-day conditions and in zero-Gulf Stream conditions.
Scroogle
quite suprisingly to me that slashdot readers seem much less enthusiastic to studies about simulations than other computer topics.
fact is: climate simulations can only reproduce the last 50 years when human produced greenhouse gases are taken into account. they fail, without them.
further readings are given at www.ipcc.ch
beside some very few, all scientists, including Americans, are standing behind these results.
Hmm... I would expect larger natural temperature fluctuations over 50 years...
Also, a crucial input to any model of this kind is the heat capacity of the ocean. AFAIK, it is not known to any (useful) degree of precision.