Question: Have we reached the tipping point of positive feedback cycles to make the effects of global warming irreversible?

Sara Imari Walker answered on 15 Jun 2011:

Hi timkellett. I don’t think so. I think we don’t know enough about global warming to know if it is reversible or not. The present state of global warming is definitely a result or at least enhanced by man’s activities over the last 150 years. However, Earth regularly goes through temperature fluctuations (the ice ages are one example – there was even a global ice age in the past called snowball Earth long before humans were around), and it was much more tropical all over Earth when the dinosaurs were around. The Earth has mechanisms for regulating its temperature and has never completely run off in one direction or another (either hot or cold – except maybe for the snowball earth episode but even at that it recovered). It may take a while, a very long while because Earth is slow at these things, but I don’t think there is any such thing as irreversible climate change. Maybe we can learn to help Earth out and make our planet better for everybody =)