ANDREW WATSON: There will be substantial climate change whatever we do. If we do nothing over the next 20 years, it will be catastrophic. If we do nothing over the next 50 to 100 years, it might even be terminal.

PETER COX: The issue is, we’ve pushed the system that does regulate itself beyond where it normally regulates. And that’s why there’s a possibility that what were previously stabilising effects become destabilising.

They are particularly concerned about secondary feed-back loops kicking in.

The segment foreshadowed a session on climate change on the Science Show today (12.10pm repeated 7.10pm Monday).

Be there, if you’re concerned about the future of the planet!

Clearly the notion that the planet will become “uninhabitable” is unwarranted and the RealClimate author makes the point later in the thread that no scientist would go there.

I have to say that I don’t claim any great knowledge on global warming and climate change. I got my head into it for a weekend a couple of years ago and felt impelled to do a guest post at Quiggin’s place. I normally spend most of my time away from computer screens and indeed reading, so while I’m interested and concerned I can’t really keep up. I found I had RealClimate bookmarked, but I haven’t been reading it regularly.

I got lost there for a while tonight. By following some links I found I shouldn’t worry about polar bears. I do hope the man is right.

I found a fascinating post and discussion on tipping points which brings the whole global warming debate into focus. I’d highly recommend it.

On that thread I was reminded that there are other things to worry about, for example the effects of acidification on plankton and other small critters in the sea.

I also found a response by Daniel C. Nepstad the senior scientist from Woods Hole responding to the alarmist article in the Independent. But it included this:

We also know that the amounts of carbon that may be going to the atmosphere following Amazon droughts are probably big enough to accelerate global warming. Currently trends suggest that a big chunk of the Amazon forest will probably be displaced by fire-prone scrub vegetation; global warming will probably exacerbate this trend.

It’s a worry, but what I’m struggling with is how big a worry is it? How likely is it to happen and what are the implications on the global climate (leaving aside the direct local effects?

I’m not any the wiser really except that it seems that the ice we are skating on is thinner than we thought.

It is clear that there are multiple factors at work. The local destructive activity is probably the worst. The warming of the oceans to the north seems part of the problem. So does the ENSO factor as we seem to be promised more El Nino’s in the future. The new research simply shows that the forest may be more fragile than we thought. And those 73,000 fires last year really worried me.

But in the end it is a case of systems within systems and systems interacting with other systems and all of them chaotic. I thought this comment captured it pretty well.

This is where James Lovelock’s approach goes beyond James Hansen’s, I think. (I quoted Hansen endlessly on the Greenland thread. Hansen says we are now in charge of the climate because what we do makes the difference. Lovelock wouldn’t deny this, nor would he deny the need to take concerted action. His proposals are in fact more radical, but the important aspect is that we should allow Nature the space and scope to repair herself. We need, he says, to effectively vacate a third of the planet, and not just the less useful bits, in order to allow natural systems (which we can never hope to fully understand) to find a new balance.

He says things last really went off the rails 55 million years ago. Then because of methane emissions comparable to the carbon we are putting into the air now (but 30 times more quickly) the temperature rose to 5C higher than now at the equator and 8C higher in the temperate zones. This was very adverse to life. But a more favourable balance was eventually achieved in the carbon distribution, but it took 200,000 years and the important process that turned things around involved the weathering of rocks.

So our future may or may not include an Amazon rainforest as we know it. But I hope we don’t have to go the long way round to lose and regain a liveable planet.

It’s not as extreme as the Independent article, but still concerned. I read that blog regularly, and it still scares me – but probably more than the occasional regular media sensationalist article, because it piles on the overwhelming scientific evidence that things are happening, and faster than scientists expected (Greenland ice sheet melting is probably the biggest one of these).

I decided to delete the second paragraph of your comment, rather than all of it as you suggested, but things are getting pretty repetitive in a way and a bit too personal at times as well for my liking.

I’ll comment on some matters others have raised later.

That is one of the batshit craziest things I’ve read in… well, just about forever.

Only someone ignorant of the what kind of a life-form Birdie is would say this.

If you have been paying any attention at all you’d know that Birdie is a submarine C02 breather.

Yes, Birdie is a stromatolite!

http://stromatolite.brainsip.com/