The main reason for payment to protect tropical forest is that land use change, primarily deforestation, accounts for around 18 to 25% (or maybe even more if soil carbon is properly factored in) of current CO2-equivalent greenhouse gas emissions. Reducing deforestation is not just a relatively cheap way of reducing emissions, it has other benefits (you get to keep the forest goods and services) that don't emerge from other solutions. But in all honesty, we need every method of reducing emissions we can get. We can't just sit back and go 'oh, it's too late'.
That said, marine biologists are -very- wary of iron seeding, plankton blooms being generally bad for other sea life. Its unclear whether its effective in carbon terms, but some private co's already marketing credits for small-scale efforts.
Temperature experiments - plants will only take up more CO2 if conditions for growth are improving - longer growing season in temperate realms, and better average weather. Those seem to have been grassland plants getting hotter and drier. Response doesn't hold for tropical plants getting warmer and wetter (common projection for W Amazon), which as an ecosystem (not all species) should encourage growth.
Probably, tropical forests have been putting on biomass to date, taking advantage of a bit more warmth and CO2, but the thinking seems to be that this will peak shortly. There's a live debate around these trends (e.g. http://www.citeulike.org/user/Flit/article/2507850).
Boreal forests are projected to spread, increasing carbon storage and possibly protecting peat bogs from temperature-induced degradation, but changing the albedo because forests hold snow for a shorter period. Considering only the albedo versus carbon uptake balance suggests that boreal spread will have a net warming effect (http://www.citeulike.org/user/Flit/article/1281557), but afaik no-one has done the sums for the soil carbon.
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timeasmymeasure
no subject
Date: 2008-09-26 10:31 am (UTC)The main reason for payment to protect tropical forest is that land use change, primarily deforestation, accounts for around 18 to 25% (or maybe even more if soil carbon is properly factored in) of current CO2-equivalent greenhouse gas emissions. Reducing deforestation is not just a relatively cheap way of reducing emissions, it has other benefits (you get to keep the forest goods and services) that don't emerge from other solutions. But in all honesty, we need every method of reducing emissions we can get. We can't just sit back and go 'oh, it's too late'.
That said, marine biologists are -very- wary of iron seeding, plankton blooms being generally bad for other sea life. Its unclear whether its effective in carbon terms, but some private co's already marketing credits for small-scale efforts.
Temperature experiments - plants will only take up more CO2 if conditions for growth are improving - longer growing season in temperate realms, and better average weather. Those seem to have been grassland plants getting hotter and drier. Response doesn't hold for tropical plants getting warmer and wetter (common projection for W Amazon), which as an ecosystem (not all species) should encourage growth.
Probably, tropical forests have been putting on biomass to date, taking advantage of a bit more warmth and CO2, but the thinking seems to be that this will peak shortly. There's a live debate around these trends (e.g. http://www.citeulike.org/user/Flit/article/2507850).
Boreal forests are projected to spread, increasing carbon storage and possibly protecting peat bogs from temperature-induced degradation, but changing the albedo because forests hold snow for a shorter period. Considering only the albedo versus carbon uptake balance suggests that boreal spread will have a net warming effect (http://www.citeulike.org/user/Flit/article/1281557), but afaik no-one has done the sums for the soil carbon.