Wednesday, January 11, 2006

Ronald Reagan was right! Forests harming the earth.

Swampy: Chop a tree and save the Earth. That means open season on melaleuca trees in Florida.

"They have long been thought of as the antidote to harmful greenhouse gases, sufferers of, rather than contributors to, the effects of global warming. But in a startling discovery, scientists have realised that plants are part of the problem. According to a study published today, living plants may emit almost a third of the methane entering the Earth's atmosphere. The result has come as a shock to climate scientists. "This is a genuinely remarkable result," said Richard Betts of the climate change monitoring organisation the Hadley Centre. "It adds an important new piece of understanding of how plants interact with the climate." Methane is second only to carbon dioxide in contributing to the greenhouse effect. "For a given mass of methane, it is a stronger greenhouse gas, but the reason it is of less concern is that there's less of it in the atmosphere," said Dr Betts. But the concentration of methane in the atmosphere has almost tripled in the last 150 years, mainly through human-influenced so-called biogenic sources such as the rise in rice cultivation or numbers of flatulent ruminating animals. According to previous estimates, these sources make up two-thirds of the 600m tonnes worldwide annual methane production. Frank Keppler, of the Max Planck Institute for Nuclear Physics, who led the team behind the new research, estimated that living plants release between 60m and 240m tonnes of methane per year, based on experiments he carried out, with the largest part coming from tropical areas. David Lowe, of the National Institute of Water and Atmospheric Research in New Zealand, said the new work, published in Nature, is important for two reasons. "First, because the methane emissions they document occur under normal physiological conditions, in the presence of oxygen, rather than through bacterial action in anoxic environments," he wrote in an accompanying article. "Second, because the estimated emissions are large, constituting 10-30% of the annual total of methane entering Earth's atmosphere."
The last part amuses me.
"....In addition, the new research could help to explain the source of plumes of methane observed by satellites over tropical forests. "The sheer biomass of the forest may be a factor there," said Dr Mahli. The fact that plants produce methane does not mean that planting forests is a bad idea, however. "Putting a tree where there was no tree before locks up a lot of carbon and this [new research] perhaps reduces the overall benefit of that by a fraction," said Dr Mahli. Some mysteries remain: how and why plants produce methane is unclear. Dr Keppler's team said the search for an answer is likely open up a new area of research into plant biochemistry."
Then right below other surprise findings(previous post here) that should have been common sense, especially the first. Imagine planting trees that have to survive by water and nutrients in the soil can change the eco-system around it. What a shock. This doesn't square well with Dr. Mahli's point that planting forests is not a bad idea.
Other surprise results Tree planting Researchers in North Carolina found that planting trees to soak up carbon dioxide can suck water and nutrients from the ground, dry up streams and change the soil's mineral balance Aerosols A recent study in Nature found cutting air pollution could trigger a surge in global warming. Aerosols cool the Earth by reflecting radiation back into space. Scrapping them would have adverse consequences Global dimming In 2003 scientists noticed levels of sunlight reaching the Earth's surface had dropped by 20% in recent years because of air pollution and bigger, longer-lasting clouds

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