Our weather will be on crusie control into the weekend…so enjoy.  The following was an interesting story published in the most recent issue of the Bulletin of the American Meteorological Society. Just another example of how complicated our atmosphere/biosphere is and how other things, other than carbon dioxide, can influence global temperature and circulation…Â
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REEXAMINING THE EFFECTS OF BURNING FORESTS Â Â Â Â Â Â Â Â Â Â Â
AMERICAN METEOROLOGICAL SOCIETY
Most scientists concur that the recent increase in global temperÂatures has been especially proÂnounced at the poles. One very noticeable effect is that high-latitude, or boreal, forests have been particularly susceptible to fires in recent years. ResearchÂers studying the climatic impact of fires in Earth’s northern forÂests, however, recently made the unexpected discovery that for a long period of time following these fires, global temperatures will drop. This contradicts the predictions of many who believe that increased carbon released from the fires into the atmoÂsphere will have a warming efÂfect, and that this warming will lead to more fires, creating a potentially runaway cycle.
The new study, however, found that while the short-term effect of the fires is the expected increase in temperature, the long-term effect is the growth of great amounts of deciduous trees, which have large, light-colored leaves that reflect sunlight, more than offsetting the carbon effect and eventually leading to cooler temperatures. In addition, these new trees lose their leaves during the winter, leaving exposed snow on the ground that also reflects sunlight and contribÂutes to the cooling effect.
The research, which is disÂcussed in a recent issue of Science, focused on the 1999 Donnelly Flats fire in Alaska , which burned almost 19,000 acres. The species of tree most affected by the Donnelly fire was the black spruce, which has thin, dark needles. The scientists found that the majority of the trees that grew immediately after the fire were aspen, birch, and other deciduous trees, which have larger, lighter leaves than the black spruce. Computer models reveal that immediately after the fire, the release of carbon caused an increase in temperature, but within 10-15 years, a cooling effect takes place. Although the black spruce will eventually re-grow, it will take a very long time for them to become so prevalent that they again influence temperatures.