NASA warns of coming climate change
2004 03 08
 The idea that global warming could send North America and Western Europe into an ice age within a few decades can no longer be called a conspiracy theory by skeptics, now that NASA is taking it seriously.
According to the NASA website: "The thawing of sea ice covering the Arctic could disturb or even halt large currents in the Atlantic Ocean. Without the vast heat that these ocean currents deliver…Europe's average temperature would likely drop 9 to 18°F, and parts of eastern North America would be chilled somewhat less. Such a dip in temperature would be similar to global average temperatures toward the end of the last ice age roughly 20,000 years ago. Some scientists believe this shift in ocean currents could come surprisingly soon—within as little as 20 years…"
"It's difficult to predict what will happen," says NASA’s Donald Cavalieri, "because the Arctic and North Atlantic are very complex systems with many interactions between the land, the sea, and the atmosphere. But the facts do suggest that the changes we're seeing in the Arctic could potentially affect currents that warm Western Europe, and that's gotten a lot of people concerned."
NASA has satellites reporting on the ice cover in the Arctic, which show "a long-term decline in the 'perennial' Arctic sea ice (the part that remains frozen during the warm summer months)…This year-round ice has been retreating since the beginning of the satellite record in 1978 at an average rate of 9% per decade."
Melting Arctic sea ice could "dump enough freshwater into the North Atlantic to interfere with sea currents…Retreating ice cover exposes more of the ocean surface, allowing more moisture to evaporate into the atmosphere and leading to more precipitation.
"Because saltwater is denser and heavier than freshwater, this 'freshening' of the North Atlantic would make the surface layers more buoyant. That's a problem because the surface water needs to sink to drive a primary ocean circulation pattern known as the 'Great Ocean Conveyor.' Sunken water flows south along the ocean floor toward the equator, while warm surface waters from tropical latitudes flow north to replace the water that sank, thus keeping the Conveyor slowly chugging along. An increase in freshwater could prevent this sinking of North Atlantic surface waters, slowing or stopping this circulation."
NASA says that, "Once considered incredible, the notion that climate can change rapidly is becoming respectable."
Article From: http://www.unknowncountry.com/news/?id=3611
|
