CLOGGED SINKS, CLIMATE TROUBLE

As emissions increase, carbon 'sinks' get clogged; World's oceans, forests becoming less able to absorb CO2
Juliet Eilperin, December 3, 2009 (Washington Post)

"In the race to reduce greenhouse gases in the atmosphere, scientists have been looking to forests and oceans to absorb the pollution people generate.

"Relying on nature to compensate for human excesses sounds like a win-win situation -- except that these resources are under stress from the very emissions we are asking them to absorb, making them less able partners in the pact…The benefits of these natural carbon "sinks" are many: Their diverse ecosystems soak up carbon dioxide. What's more, the international carbon enables industries to compensate for their emissions at a fraction of the price of installing cleaner technology, essentially by investing in forests; meanwhile, poorer countries that are rich in woodland profit from selling not lumber but carbon credits."

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"…[A] global society of conservation biologists has launched a lobbying campaign, asking key decision-makers -- from the Danish officials chairing next week's climate talks in Copenhagen to U.S. lawmakers -- to push for steeper emission cuts to ensure that humans do not exhaust forests' capacity to store carbon in the decades to come…[T]he drought-stressed Amazon rain forest emitted roughly as much carbon dioxide in 2005 as it usually stores -- about the same amount as the European Union and Japan together emit in a single year…[T]he proportion of fossil-fuel emissions absorbed by the oceans since 2000 may have declined by as much as 10 percent…[because] oceans are becoming more acidic as more carbon dioxide enters the atmosphere, so they are losing their ability to soak up emissions produced by people…

"According to the Global Carbon Project, which tracks emissions, land and ocean carbon sinks took up 57 percent of human-generated carbon emissions between 1958 and 2008. While the size of these sinks has expanded in the past few decades, their absorption rate is slowing as greenhouse gas emissions have risen (by 41 percent since 1990)…[F]uture drought and other factors make it difficult to determine what the exact rate of absorption will be…[T]he Amazon has now returned to soaking up carbon rather than emitting it, but it's projected to be drier in future decades. To the north, Canada's boreal forest has suffered pine-beetle infestation on 51 million acres, an area half the size of California, which can lead to a massive carbon release as trees die off…"

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"The calculations matter because countries such as Brazil, which has pledged to reduce its deforestation rate 80 percent by 2020, are planning to receive money for these reductions as part of an allowance-trading system through the carbon market…Some environmentalists argue that the fact that forests are becoming less efficient carbon sponges should not lessen the incentive for preserving long-standing [old growth] forests in developing countries…more effective at storing carbon because the trees are bigger…

"New research does point to one promising new avenue of natural carbon sequestration: coastal salt marshes, mangroves and seagrass meadows…But human activity is eroding these coastal habitats…"