Question: what role will rainforests and other carbon trapping ecosystems have in the global climate in the next century?

Murray Collins answered on 23 Mar 2011:

Hi again

What role they play next century really depends how this century goes. If we have loads of warming this century, and it seems likely that we will, then many ecosystems will undergo huge change. Scientists always have a degree of uncertainty when they make predictions, however some people who model the way rainforest work think that continued climate change will lead to drying of many rainforest ecosystems and cause them in some places to collapse and make a transition into another system. This would be really bad news for us, as rainforests are so important in regulating global functions like rainfall, and of course carbon sequestration. In fact it would be part of a larger suite of changes called positive feedbacks, whereby the changes caused by climate change will lead to increasing release of climate change inducing gases. All the carbon released from a dying rainforest would be one of these. If we ever actually do witness something like this then humans will be in a lot of trouble in a lot of places!

So, one of the major objectives of ecosystem management at the international and national level is trying to make sure these systems are as resilient as possible to climate change, which in forests would be doing things like reducing the amounts of road we build into them, keeping larger areas in tact etc.

So to really answer your question I would say that carbon sequestering ecosystems (particularly peat swamps, but also including grasslands and other systems) have a huge role to play into the future, but whether they can or not depends on how we manage them now! I honestly don’t think this is a choice we have though. I mean by this that the value of the biosphere, which supports life on earth, and of which ecosystems are component parts is infinite. If there were no ecosystems we couldn’t live. Someone asked if we could build artificial rainforests, and I seriously think we have got to abandon completely any idea that we can simply replace what nature we destroy with technology! Even if we can do some things artificially, like filter water in sewerage treatment, a) this is extremely expensive, whereas nature does these things for free, b) we simply couldn’t scale up and replace the ecosystem functions that we need for life on earth.