this troubles me ...

Long term global temperature cycles might follow a random to irreugular sine curve over 10's to 100's of 1000's of years.

Along that random sine curve there are random short term dramatic fluctuations over 1's to 10's to 100's of years.

Kinda of like the share price of a company like BHP or CBA over say 20 years ... big cycle trends and fluctuations within channels.

What troubles me about the climate change argument which is has been discussed noe for perhaps 10-20 years is how can it be determined that the debate is not being being based on one of these random short term fluctuations rather than something associated with a trend occupying even 5000 to 10,000 years (the crux question of this post)?

Scientific theories with some but not complete observational support and some (real or unreal) connection to perceived reality are ferociously difficult to debate (climate change, chloresterol etc).

In the case of the possibility of climate change, the concept that an industrialised global economy 200 years or so old has spit out enough emmissions to impact climate is at some level plausible and is grasped by those that are receptive.

The trouble with climate change being inextricably linked to environmentalism is that if climate change is debunked, environmental causes will be set back for decades ... there is much at stake.

Dex