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Will a mini ice age result from global warming? by Tim Jones 06 August 2003 21:02 UTC |
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"As we continue to pile on atmospheric carbon dioxide, we're going to have more unintended consequences," says William Curry, a climate scientist. "We need to seriously consider steps to curb greenhouse gases."
But first things first. Isn't the earth actually warming?
Indeed it is, says Joyce. In his cluttered office, full of soft light from the foggy Cape Cod morning, he explains how such warming could actually be the surprising culprit of the next mini-ice age. The paradox is a result of the appearance over the past 30 years in the North Atlantic of huge rivers of freshwater-the equivalent of a 10-foot-thick layer-mixed into the salty sea. No one is certain where the fresh torrents are coming from, but a prime suspect is melting Arctic ice, caused by a buildup of carbon dioxide in the atmosphere that traps solar energy.
The freshwater trend is major news in ocean-science circles. Bob Dickson, a British oceanographer who sounded an alarm at a February conference in Honolulu, has termed the drop in salinity and temperature in the Labrador Sea-a body of water between northeastern Canada and Greenland that adjoins the Atlantic-"arguably the largest full-depth changes observed in the modern instrumental oceanographic record."
The trend could cause a little ice age by subverting the northern penetration of Gulf Stream waters. Normally, the Gulf Stream, laden with heat soaked up in the tropics, meanders up the east coasts of the United States and Canada. As it flows northward, the stream surrenders heat to the air. Because the prevailing North Atlantic winds blow eastward, a lot of the heat wafts to Europe. That's why many scientists believe winter temperatures on the Continent are as much as 36 degrees Fahrenheit warmer than those in North America at the same latitude. Frigid Boston, for example, lies at almost precisely the same latitude as balmy Rome. And some scientists say the heat also warms Americans and Canadians. "It's a real mistake to think of this solely as a European phenomenon," says Joyce.
Having given up its heat to the air, the now-cooler water becomes denser and sinks into the North Atlantic by a mile or more in a process oceanographers call thermohaline circulation. This massive column of cascading cold is the main engine powering a deepwater current called the Great Ocean Conveyor that snakes through all the world's oceans. But as the North Atlantic fills with freshwater, it grows less dense, making the waters carried northward by the Gulf Stream less able to sink. The new mass of relatively fresh water sits on top of the ocean like a big thermal blanket, threatening the thermohaline circulation. That in turn could make the Gulf Stream slow or veer southward. At some point, the whole system could simply shut down, and do so quickly. "There is increasing evidence that we are getting closer to a transition point, from which we can jump to a new state. Small changes, such as a couple of years of heavy precipitation or melting ice at high latitudes, could yield a big response," says Joyce.
In her sunny office down the hall, oceanographer Ruth Curry shows just how extensive the changes have already become. "Look at this," she says, pointing to maps laid out on her lab table. "Orange and yellow mean warmer and saltier. Green and blue mean colder and fresher." The four-map array shows the North Atlantic each decade since the 1960s. With each subsequent map, green and blue spread farther; even to the untrained eye, there's clearly something awry. "It's not just in the Labrador Sea," she says. "This cold, freshening area is now invading the deep waters of the entire subtropical Atlantic."
"You have all this freshwater sitting at high latitudes, and it can literally take hundreds of years to get rid of it," Joyce says. So while the globe as a whole gets warmer by tiny fractions of 1 degree Fahrenheit annually, the North Atlantic region could, in a decade, get up to 10 degrees colder. What worries researchers at Woods Hole is that history is on the side of rapid shutdown. They know it has happened before. "
Date: Tue, 5 Aug 2003 22:22:56 -0500 To: KenRichard2002@aol.com From: Tim Jones <deforest@austin.rr.com> Subject: Re: Good news and bad news from "Daily Grist" Cc: Bcc: X-Attachments: At 10:14 PM -0400 08/05/2003, KenRichard2002@aol.com wrote:One thing to think about is the fact that the global warming is going to generate more trees and plant life which should help to bring about more rainfall. You have to remember that trees and plant life are giving way to crops all over the world and perhaps the warming climate may attenuate those circumstances to some degree.I wouldn't be too complacent about climate change. Ironically we could be in an ice age in twenty years. Ie. glaciation of the northern hemisphere due all that rain you're talking about.
The heat engine created by warming appears to be creating more extreme weather events every year. More tornadoes. More and worse hurricanes are forecast, heat waves, droughts, flooding are upon us.... Coastal and lowland flooding due to the melting of the polar ice caps will be catastrophic for many. More extinctions of biological diversity will follow ecosystem shift due to warming than will be revived I think. The glaciers are melting. The tundra is thawing (more carbon dioxide). We are in a period of extreme mass extinction of higher vertebrate animals ( except man and his chattel.) Climate change is not going to help this, it will accelerate it.
<http://calspace.ucsd.edu/virtualmuseum/climatechange1/cc1syllabus.shtml>
http://calspace.ucsd.edu/virtualmuseum/climatechange2/12_1.shtml
(excerpt)
Climate Change and Extinction
The effect of global warming, it may be safely assumed, will be to accelerate the process of extinction. The reason is that plants (and therefore the animals that depend on the plants) are adapted to a certain range of conditions for their growth and reproduction. For example, a plant in temperate latitudes is genetically programmed so that it "knows" frost will come when the days become shorter. Thus, sometime in fall, a deciduous tree will shut down and shed its leaves, preventing the frost from freezing the sap in the tree and damaging it. However, more opportunistic plants with a higher tolerance for risk, like brush, will not shut down in fall but wait until it gets cold. These plants, in a situation of warming, will win the battle for sunlight which plants commonly wage. The deciduous trees will make room for brush since trees walk but slowly. Although such a local extinction can be reversed in principle, a sufficient number of local extinctions will add up to global extinction.
And while many attribute the thinning of the ozone layer for increased rates of skin cancer you have to consider that the majority of new cases are coming about in areas such as Australia and similar climates (where people have historically and genetically evolved to have darker complexions.)
It's the white Australians of European ancestry getting the skin cancer.KRTim -- <http://www.groundtruthinvestigations.com/>
-- <http://www.groundtruthinvestigations.com/>
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