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Forests, after all, cool the atmosphere by drinking in carbon dioxide from the air. A new study, however, published in Proceedings of the National Academy of Sciences reports that forests' other climatic effects can cancel out their carbon cleaning advantage in some parts of the world. Using a three-dimensional climate model, the research team mimicked full global deforestation and also studied the effects of clear-cutting in different regions of latitude, such as the tropics and boreal zones. Apparently, these natural carbon sinks only do their job effectively in tropical regions; in other areas, they have either no impact or actually contribute to warming the planet. In fact, according to this model, by the year 2100, if all the forests were cut and left to rot, the annual global mean temperature would decrease by more than 0.5 degree Fahrenheit.
More Trees, Less Global Warming, Right? -- Not Exactly
Article Source: Sciam- Enjoy this article? Help vote it up the 'Vine.
- Public Discussion (3)
Trees perform three major climate functions:
- They absorb carbon, which they pull from the atmosphere, creating a cooling effect;
- their dark green leaves absorb light from the sun, heating Earth's surface;
- and they draw water from the soil, which evaporates into the atmosphere, creating low clouds that reflect the sun's hot rays (a mechanism known as evotranspiration that also leads to cooling).
How about this rephrasing:
- They absorb carbon, which they pull from the atmosphere, thus more trees means less Greenhouse Effect;
- their dark green leaves absorb light from the sun, making them one of the principal cog wheels of life on earth, the primary mechanism of capturing the energy from the sun without which we'd be doomed;
etc...
And how about:
- They hold grab and moisturise soil - without trees ecosystems erode and desertify;
- they are homes to millions of other life forms, birds, mammals, insects, microbes, fungae whose existence would be endangered without trees and who in turn themselves are cog wheels in other parts of earth's complex ecosystem;
- they themselves provide valuable ecosystem services to Mankind - fruits, nuts, timber, medicine, biofuel, shade etc, etc...
These three factors—the second two being largely ignored in climate models up to this point
It's true that the public focus has been on tree's role as carbon sinks, but I really don't believe photosynthesis and cloud formation has been 'largely ignored' in serious climate and ecosystem models.
In tropical zones, forests have a significant, overall cooling effect. [...] If a forest covers a snowy expanse, "that has a strong warming influence," [...] because of little cloud cover resulting from less efficiency in evaporating water. The poor cloud formation coupled with the intense absorption of light by the trees "far overwhelms the cooling influence of the carbon storage," he says.
Smart: a global air conditioning installation. Cools the tropics, heats the cold areas. Heating local, already cold, areas is not a problem in relation to over all global Greenhouse Effect.
Don't get me wrong, the study is interesting. I just fear some could get the wrong message from the article. Also, let me quote the final paragraph hidden on the article's second page:
[...] protecting the forest should be part of an effort to sustain the world's biodiversity. [...] the findings do not endorse clear-cutting or destroying wildlife habitats. "I think that it's important to look at preventing climate change as a means rather than an end in itself [...] Too narrow a focus on global warming and a loss of the broader focus of protecting life on this planet can lead to perverse outcomes." Rather than looking to forests to solve the current climate crisis by capturing carbon dioxide, he suggests targeting our "energy system," which continues to create the pollutant.
- 1 vote
#1 - Mon Apr 16, 2007 5:22 AM EDTHere's another article about the same study, but with some slightly different points: Could global deforestation fight climate change?
the expected climate-fueled expansion of boreal forests in the future will worsen global warming, making some places up to 10 degrees Fahrenheit warmer by 2100 than they are today. [...] In comparison, tropical forests cool the planet by storing large amounts of carbon and producing reflective clouds increasing surface albedo. [...] "The destruction of ecosystems to prevent global warming would be a counterproductive and perverse strategy"
- 1 vote
Back-handedly this seems to correlate with the mini-ice age experienced in the late 18th and early 19th century in the U.S., in which massive deforestation in a temperate climate seemed to lower temperatures.
The world's a complex place, thanks very much for the science.
- 1 vote
#2 - Tue Jun 19, 2007 8:05 PM EDTYou're in Easy Mode. If you prefer, you can use XHTML Mode instead. |
