Climate change is certainly nothing new... I think (and I'm no expect here) that people are taking their 'best guess'.
Making drastic and unrealistic claims based on a constantly changing pool of data is not the right way to approach this... however ignoring that
something is going on, is equally incorrect.
Fact of the mater is that we have more greenhouse gases right now then ever before, and they are deteriorating the ozone layer... now what that means for our climate is yet to really be seen... but to think it wont affect it is unrealistic.
So people make educated guesses based on Data which (as we have seen by the constant flip-flopping of 'experts') is far from conclusive... And although the climate change may be a natural cycle which has nearly nothing to do with our greenhouse gases, the average temperature today, is higher than it was 50, 20, or even 10 years ago... and its increase happens to correlate closely with the increase in greenhouse gases.
But if you want to scream the sky is falling, there is a 1 in 38 chance that the earth ends via asteroid impact in 18 years... I'd consider that to be much more deserving of the hysteria
