Well I’m always ready to discuss global warming, and to change my stance. Indeed I’ve gone from ‘yes, in theory that’s true’ in the mid-1970s to ‘by golly this is bad’ by 2005. If evidence turns up to the contrary I’ll have an open mind… but so far it just gets grimmer. Ice caps melting, species dieing, bears failing to hibernate… and it hasn’t rained to our expectations here in Sydney, Australia for nigh on 10 years. But what has puzzled me most are the people willing to just argue a minor point – namely that “the Earth has always done this”, ie that we have a natural cycle of warming and cooling anyway, so what’s the big deal? Well I’ve tried to say sure, there is a natural cycle – indeed we are in the latter stages of the warm phase now – but this time around we have added our own little carbon dioxide experiment to the mix. We didn’t run this experiment in the last ice age, in fact we’ve never run this little game before – certainly not at this scale. So to my mind we – not nature (whatever that is) – may have added too much oomph to the warm phase – and we may not pull up into another ice age at all. At the very least we are foolish to run experiments like this when we don’t know what the real impacts may be. What if it’s a threshold-based system, where you reach a ceratin point and it simply takes off - do we want to sit on our hands waiting to see what happens, or do we take arms against a sea of troubles and by opposing – with some luck – end them?