Global Warming or the New Ice Again
Global warming is an inescapable issue for our age. Simply 180 years ago, about scientists believed that Earth had been steadily cooling since information technology was formed. When Louis Agassiz presented the concept of a Corking Water ice Age to the Swiss Society of Natural Sciences in 1837, his proposition that the planet had turned colder and and then warmed up over again was met with skepticism and fifty-fifty hostility, triggering years of fierce scientific contend before the thought was accepted.
Exactly why our planet occasionally cools down has taken more than a century to work out. Now we know that cyclic gravitational tugs from Jupiter and Saturn periodically elongate Earth's orbit, and this effect combines from time to time with boring changes in the direction and degree of Globe's tilt that are caused past the gravity of our large moon. Consequently, summer sunlight around the poles is reduced, and high-latitude regions such every bit Alaska, northern Canada, and Siberia plough cold enough to preserve snow yr-round. This constant snowfall embrace reflects a great deal of sunlight, cooling things downwards fifty-fifty more, and a new ice historic period begins. Naturally, this procedure does non occur with anything like the speed portrayed in the movie The Day After Tomorrow, but geological and other evidence shows that it'southward happened at least four times.
With so much attending focused on global warming, this chilly prospect has been all but forgotten. Given how catastrophic some other ice age could be, one might be tempted to inquire whether a human being-acquired increment in atmospheric and sea temperatures volition actually exist a benefaction.
There's little question that global warming is happening. Climate data testify that Earth'south average temperature has risen at least 0.7 oC (1.iii oF) over the 20th century. Temperature increases over the 21st century will probably be two and a half to 5 times as large,considering greenhouse gases similar carbon dioxide allow sunlight to penetrate the atmosphere just make information technology harder for outgoing infrared radiation to escape. What'due south more, just as carbonated soda fizzes when it warms upward, warmer temperatures cause the body of water to release carbon dioxide taken up during colder periods. Analyses of air trapped in glacial water ice over the terminal 800,000 years show that atmospheric carbon dioxide more often than not ranged between 200 and 300 parts per one thousand thousand past book (ppmv); increases in these levels were slightly preceded by increases in temperature caused by natural orbital shifts. During this period, global temperature varied by about 12 oC. Now, carbon levels are budgeted 400 ppmv every bit the burning of fossil fuels pumps more and more carbon dioxide into the atmosphere. Even if the rate of growth could be moderated enough to stabilize levels at about 550 ppmv, average temperatures might well rise past nearly 5 oC–with devastating effects for united states of america earthlings, such every bit rise sea levels and dramatic changes in weather patterns.
Just even that warming will not stave off the eventual render of huge glaciers, because water ice ages last for millennia and fossil fuels will non.In about 300 years, all bachelor fossil fuels may well have been consumed.Over the following centuries, excess carbon dioxide will naturally dissolve into the oceans or get trapped by the formation of carbonate minerals. Such processes won't be offset by the industrial emissions nosotros come across today, and atmospheric carbon dioxide will slowly decline toward preindustrial levels. In about ii,000 years, when the types of planetary motions that can induce polar cooling start to coincide over again, the current warming trend will be a afar retentivity.
This means that humanity will be striking by a ane-two punch the likes of which we have never seen. Nature is as unforgiving to men as it was to dinosaurs; avant-garde civilization will non survive unless nosotros develop energy sources that curb the carbon emissions heating the planet today and help us fend off the cold when the water ice age comes. Solar, nuclear, and other non-fossil-fuel energy sources need to exist developed now, before carbon emissions go out of hand. MIT alumni could play a prominent part in discovering the technology needed to keep us all going. And there are fortunes to be made from the try. It's worth thinking about.
Professor Franklin Hadley Cocks '63, SM '64, ScD '65, teaches free energy engineering and climate-related courses at Knuckles Academy and is the author of Energy Demand and Climatic change (Wiley-VCH), which summarizes free energy and climate issues of the past, present, and future.
Source: https://www.technologyreview.com/2009/12/21/207026/global-warming-vs-the-next-ice-age/
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