Tuesday, 10 June 2008

Ghost forests and acid seas

Map courtesy of World Resources Institute
The release of carbon dioxide by ghost forests (due to pine beetles) is "greater than the uptake of all the forest of B.C." says the lead researcher of a study just published in Nature. According to Werner Kurz of the Canadian Forestry Service, by 2020 the dead trees will release 270 megatonnes of carbon dioxide into the atmosphere.

Eyeballs must be popping in Ottawa. That's exactly the amount of greenhouse gas emissions Canada is committed to reducing by 2012 under the Kyoto Protocol, and the beetles' damage would effectively doom that effort to failure.
The size of a grain of rice, the beetle lays its eggs under the bark of mature lodge-pole pine and jack pine trees. Once infested, a tree's fate is sealed. By the end of 2006, 130,000 square kilometres (more than 50,000 square miles) of forests were reported dying in western Canada. The latest outbreak, driven by climate change, is ten times larger than any previous one and seems be spreading into the northern boreal forest that crosses the continent.
Photo: treehugger.com
Healthy forests are normally carbon sinks. They absorb more carbon dioxide -- the number one greenhouse gas -- than they give off. But when entire forests die, they release large amounts of CO2 into the atmosphere; few living plants survive to soak it up. Previous climate change models of northern forests failed to take the impact of the pine beetle into account.
Another major carbon sink is in danger: the oceans. Last year CSIRO scientists reported that the Southern Ocean has lost 35% of its ability to absorb CO2. The Southern Ocean around Antarctica is so loaded that it can barely absorb any more, thus more of the gas will stay in the air, adding to the greenhouse effect. Scientists fear the same could be true of all the planet's oceans, which absorb a quarter of man-made carbon dioxide emissions every year. If so, the tipping point may be much closer than the IPCC predicts.
Further reading: CBC science, Treehugger article with maps, reports from Southern and Caribbean oceans. Pine beetle impact in USA: Reuters 4 Aug 09. Forestry prof John Ball shows dying forests in 2001 in the Black Hills of SD. World Water Council 12 Feb 2013: K Mikkelson et al, Bark beetle infestations affect water quality in the Rocky Mountains of North America
Updates Feb 2016: The Beetles: Eighty-Nine Million Acres of Abrupt Climate Change by the maker of the film What Have we Done. 
Ocean extinctions forecast in http://phys.org/news/2016-04-widespread-loss-ocean-oxygen-2030s.html#jCp and http://phys.org/news/2011-12-hot-ice-age-problems.html#jCp

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