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Copenhagen: Has the Amazon tipping point tipped?

It appears that the action on Wednesday afternoon was where I was not: in the session on tipping points. Chris Jones of the Met Office’s Hadley Centre presented some studies of the Amazon (abstract in pdf) that have caused a big media stir. The studies suggest that a) there is a threshold level of warming beyond which much of the Amazon forest is committed to die back (probably being replaced by savanna) and b) that for significant parts of the forest that threshold is alarmingly low. Indeed it is quite possibly either unavoidable in the near future or already dwindling in the rear-view mirror. As I understand it from people who saw the presentation, models in which all the warming already in the pipeline (ie with no further emissions) is realised leave the forests pretty much committed to some dieback, and modest further warming seals the deal. I wasn’t able to check that with Jones himself, but it seems to fit with what he and his colleagues write:

We present results to show a possible climate threshold beyond which some dieback is committed and this commitment rises dramatically for global temperature rise above 2 degrees C, a threshold often used by policy makers in their definition of dangerous climate change. Any subsequent recovery is on such a long timescale as to make the dieback effectively irreversible on any pragmatic level.

Here’s the coverage from the Times and here’s some from The Guardian. Worth noting that it’s a single study, that there are error bars to consider and that people have in the past suggested that the Amazon is often more vulnerable in the Hadley Centre model than in most others. But still very worrying; all the more so if it were to be spun as a counsel of despair on efforts to stop deforestation on the basis that there’s no point preserving a forest that’s already doomed.

I’ll see if I can find Chris Jones, or some Brazilians, or both to talk about this with on Thursday.


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    Doug Heiken said:

    Your last point is critical. Even if forests switch from net carbon sink to carbon source we will only make the source worse and accelerate GHG emissions unless we continue to conserve forests, yes, even those that may be declining.

    When forests are already suffering from climate stress, we will only exacerbate emissions is we add anthropogenic stress to system.

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    James Hamilton said:

    None of this is being taken into consideration in REDD+ negotiations. Currently, negotiators are saying “we cant reach the 2 degree Celsius target without REDD+”, and on the other hand they are saying, “REDD+ VERs will be trade-able in carbon markets as offsets”. More worryingly, REDD+ is increasingly the being seen as “the” main mitigation tool globally, in a blind focus to capitalize forest carbon markets. There seems to be more focus on commercializing the potential 17% of emissions from forests than there is on dealing with the 87% of fossil fuels emissions in other sectors. No one however is lnking the very viability of REDD+ to the reduction in these wider emissions. Using REDD+as offsets is utterly illogical when positive feedback studies indicate they are not credible until we see the effects of committed climate change effects such as Amazon die-back.

    There is no point talking REDD+ until we nail down the 87% of wider carbon emissions. Talk of trading them as offsets is just a REDD Herring.

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