Climate change will mean new and larger tropical forests

We're told, endlessly, that climate change will mean the end of the Amazon, of the tropical forests, and the Earth will lose its lungs. It appears that this is not wholly and completely true. Actually, an increase in CO2 in the atmosphere is likely to lead to the growth of huge, new, tropical forests.

The report is in Nature and this is the important point:

Experimental studies have generally shown that plants do not show a large response to CO2 fertilization. “However, most of these studies were conducted in northern ecosystems or on commercially important species” explains Steven Higgins, lead author of the study from the Biodiodversity and Climate Reseach Centre and Goethe-University. “In fact, only one experimental study has investigated how savanna plants will respond to changing CO2 concentrations and this study showed that savanna trees were essentially CO2 starved under pre-industrial CO2 concentrations, and that their growth really starts taking off at the CO2 concentrations we are currently experiencing.“

Grasslands, savannahs and forests are in a constant battle. Savannah is the area which is being fought over at any one time: can the trees establish themselves in sufficient numbers to create forest or is there something holding them back from doing so? A lack of CO2 in the atmosphere, seems to be the limiting factor. If we increase the amount of CO2 then the trees do better and new forests grow.

Burning more fossil fuels therefore seems likely to grow several new Amazon style forests across Africa and Latin America.

This is nice for people like me who prefer the forest dwelling pygmy elephants to the larger savannah ones: but there is more to it than this as well. For the great unknown of climate change is what is sensitivity? What is the total sum of all of the positive and negative feedbacks that increased CO2 in the atmosphere will cause?

We know very well that the direct effect of a doubling of CO2 above pre-industrial levels will be a 0.7 degree increase in global temperatures. The IPCC itself points this out and it's not an amount that anyone really worries about. The worry is what happens then? Some processes will increase this number: others will reduce it. At the heart of our uncertainty about climate change is that we don't even know what all these processes are yet or what effects they will have. We can and do guess but that is what we are doing, guessing.

We tend to get told about the positive feedbacks, like the laughable one that insists that the Amazon rainforest will disappear in a holocaust of flames. We tend to hear a great deal less about the negative ones, like today's in Nature.

The thing that worries me most about the whole global warming thing is that I'm deeply unsure that we're going to get an even-handed accounting of this the most important question in the whole subject. Unlike James Delingpole (and yes I have now finished his excellent book and note that I appear on page 296 as one of the good guys) I don't think the whole thing is a scam. I do think that the economy with the truth comes at this point, where we're trying to work out how large the effects are going to be. I seriously suspect that positive feedbacks are talked up while negative ones are downplayed leading to the overall effect being exaggerated.

And of course what we're told we have to do about it, closing down industrial civilisation, is simply crazed lunacy. Better to lose all the forests than have to return to rural peasantry for all.