Show your support by donating any amount. (Note: We are still technically a for-profit company, so your
contribution is not tax-deductible.)
PayPal Acct: 
Feedback: 
Donate to VoyForums (PayPal):
| [ Login ] [ Contact Forum Admin ] [ Main index ] [ Post a new message ] [ Search | Check update time | Archives: 1, 2, 3, 4, 5, 6, 7, 8, 9, [10] ] |
| Subject: Arctic tundra thawing faster than expected | |
|
Author: jw |
[
Next Thread |
Previous Thread |
Next Message |
Previous Message
]
Date Posted: 06:41:59 03/12/07 Mon this is important because the positive feedback of darker land surface will kick in, which will accelerate warming of northern climates, increasing the loss rate of arctic and greenland ice. the forest that replaces the tundra absorbs alot more sunlight, we are turning a reflective white surface into a brown, absorbant surface. Global warming: spruce forests invade Arctic tundra www.chinaview.cn 2007-03-12 14:28:01 Adjust font size: BEIJING, March 12 (Xinhuanet) -- Forests of spruce trees are invading the Arctic tundra because of global warming and evicting and endangering species that live there quicker than scientists thought, a new study was quoted as saying Monday by news reports. Tundra is land area where tree growth is inhibited by low temperatures and a short growing season. In the Arctic, the tundra is dominated by permafrost, a layer of permanently frozen subsoil. Lichens, grasses and mosses are the only vegetation that can grow in such frigid conditions. Forests of spruce trees and shrubs neighbor these tundra areas, and the boundary where they meet is called the treeline. The permafrost thaws in summer and the tundra becomes covered in bogs and lakes, offering a unique habitat for plants. But global warming has lengthened the summer warming season and promoted tree growth, causing the treeline to encroach on the tundra. Researchers reconstructed a 300-year history of tree density and treeline position by looking at tree rings. The results show trees can invade the tundra faster than previously thought. "The conventional thinking on treeline dynamics has been that advances are very slow because conditions are so harsh at these high latitudes and altitudes," said Ryan Danby of the University of Alberta. "But what our data indicates is that there was an upslope surge of trees in response to warmer temperatures. It's like it waited until conditions were right and then it decided to get up and run, not just walk." While in many places the idea of more trees is a good one, this Arctic takeover endangers species like caribou and sheep that thrive in the tundra, as well as the native people who depend on these species for their survival. The details of the study are published in the March issue of the Journal of Ecology. Danby plans to continue his research as a part of the United Nation's International Polar Year research effort. (Agencies) [ Next Thread | Previous Thread | Next Message | Previous Message ] |