Tuesday, May 15, 2007

Seeing RED To Be Green

Two interesting pieces today, both concerning carbon "sinks" and their ability to alleviate global warming due to carbon release.

First up is a story on "Reducing Emissions from Deforestation:"
Tropical deforestation, which releases more than 1.5 billion metric tons of carbon to the atmosphere every year, is a major contributor to global climate change. Recognizing this, a group of forest-rich developing nations have called for a strategy to make forest preservation politically and economically attractive. The result is a two-year initiative, dubbed "Reducing Emissions from Deforestation" (RED), launched by the United Nations Framework Convention on Climate Change.

So is 1.5 billion metric tons per year a lot or a little? Continuing its summary of the study:
[T]he authors found that reducing deforestation rates by 50% over the next century will save an average of about half a billion metric tons of carbon every year. This by itself could account for as much as 12% of the total reductions needed from all carbon sources to meet the IPCC target of 450 parts per million of carbon dioxide in the atmosphere by the year 2100.

It also finds:
[C]omputer models that link climate effects to changes in the carbon cycle have predicted that tropical forests will survive and continue to act as a "sink" by absorbing carbon, provided that emissions can be kept under control . The efficiency of the tropical forest as a carbon sink might in fact diminish over time, but the authors expect that it will not disappear completely.

A second article considers the role of the oceans in absorbing carbon from the atmosphere and the reverse:
A University of Colorado at Boulder-led research team tracing the origin of a large carbon dioxide increase in Earth's atmosphere at the end of the last ice age has detected two ancient "burps" that originated from the deepest parts of the oceans.

The new study indicated carbon that had built up in the oceans over millennia was released in two big pulses, one about 18,000 years ago and one 13,000 years ago, said Thomas Marchitto and Scott Lehman of CU-Boulder's Institute of Arctic and Alpine Research, who jointly led the study. While scientists had long known as much as 600 billion metric tons of carbon were released into the atmosphere after the last ice age, the new study is the first to clearly track CO2 from the deep ocean to the upper ocean and atmosphere and should help scientists better understand natural CO2 cycles and possible impacts of human-caused climate change.

As a non-specialist, it does seem like the public debate about global warming seems to focus quite a lot on how much carbon is introduced into the atmosphere, rather than how much is taken out.

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