Certainly one for the Potential list…
Many have argued under the climate change mitigation banner that so-called ‘old-growth’ (let’s call them primary forests henceforth to distinguish them from [usually] younger secondary forests) do not provide net carbon uptake because most of their growth has occurred in the past. In other words, they provide a carbon store, but do not take much more out of the atmosphere once they’ve attained a certain ecological equilibrium. This was a major impediment for the argument that protecting such forests could be achieved economically by valuing them in national or global carbon-trading schemes. It was a shame considering that it seems the economic incentives to protect such forests were falling on deaf ears because (a) governments and industry tend to regard the quick turn-around option of timber extraction as more economically sensible and (b) of the difficulty of valuing ecosystem services provided by primary forests.
But not so, say Luyssaert and colleagues! After scouring an array of studies and databases they conclude that forests between 15 and 800 years of age do in fact continue to uptake carbon and so are not carbon ‘neutral’. Brilliant! With this latest evidence in hand, I hope the economic incentives to preserve the little remaining primary forests around the world and the ecosystem services they provide will encourage governments and industry to invest more in their preservation than their destruction. It’s worth noting here too that once such forests are destroyed (e.g., timber extraction), the majority of their stored carbon (both actual and potential via future carbon uptake) are released back to the atmosphere, thus exacerbating climate change. As such, valuing the preservation of pristine forests on the carbon-trading market should receive a far higher weighting that secondary plantations or other sequestration schemes.