Climate change gets scary
Last Saturday I attended a conference on climate change organised by the Campaign Against Climate Change, and it was truly scary stuff. Of course, at an event like that you're going to hear the doomiest and gloomiest stories going, but the story-tellers wern't wild-eyed loonies but calm, rational scientists.
It was the very first session that did it, a workshop entitled “How bad will the climate crisis get, and how quickly will it happen”. The second half of the question was not much addressed as the answers to the first part got too blood-curdling. We started with a presentation by David Wasdell of the Meridian Programme going through some tough science which – though he was allowed extra time for such important stuff – he still didn’t have long enough to develop properly. His conclusions (interim but plausible) came across clearly enough, though, and they deserve a paragraph to themselves for emphasis and clarity:
The climate is an unstable system and there are positive feedback mechanisms ready to destabilise it, leading to runaway heating or runaway cooling, but these are normally kept within limits by the energy input from the sun – as temperature rises/falls more or less heat is radiated until a balance is reached and the system falls back towards its original state. An unstable system within a stable system. But there comes a tipping point, like a watershed between two river systems, at which the system does not fall back towards its original state but tips over to a new state from which there is no recovery. A diagram at the Meridian website illustrates this. We are currently heading towards such a tipping point. Beyond it whatever we do climate change will be irreversible and catastrophic. We have maybe ten years to change course to stay just this side of the tipping point and keep things no worse than uncomfortable. It’s going to take a huge effort to make that change.
Second up was Dr Peter Challoner of the National Oceanography Centre. He talked about ocean currents and how they are changing. Measurements have been taken at intervals over the last 50 years of the flow of one such deep sea current which is needed to maintain the Gulf Stream, and it has dropped by around 30%. If that is correct and the trend continues then it’s bye bye Gulf Stream and northern Europe actually gets colder. That could, I suppose, be quite good news if it’s balancing runaway global warming, keeping us more or less where we are while the rest of the world goes to hell in a handcart.
Third was Mark Lynas, author and journalist, who went into a few details of what happens with each degree rise in temperature:
1° - Biodiversity is hit; bleached coral; tropical rainforest cut back; Nebraska returns to the desert it used to be, with a serious effect on food supplies; flooding of coastal areas.
2° - Ocean pH drops to level not seen in 300 million years, with serious impact on the food chain; positive feedback effects may kick in; the Greenland ice sheet goes (6m rise in sea level); Anthropocene Extinction event (see below) starts; water supplies from the Andes and the Sierra Nevada critically impacted (bang goes Californian agriculture)
3° - Much stronger storms; the Amazon basin collapses catastrophically, leading to a further 1.5° rise; one third of species lost (and lots of humans too); desertification of Spain and much of southern Africa; food supplies in decline – a net food deficit;
4° - Permafrost meltdown – methane is released; sea level rise accelerates; Himalayan glaciers disappear, leading to almost complete lack of water in Pakistan and other surrounding countries
5° - The western Antarctic ice shelf goes; Australia uninhabitable
6° - Tropics uninhabitable. At this point we have an event known as the Anthropocene Extinction, similar to the event – probably also triggered by a 6 degree warming – at the end of the Permian period 250 million years ago in which 90% of species were wiped out.
I have to emphasise that, while there is almost complete consensus in the scientific community that global warming is happening and that we are responsible, what these guys were saying is still theoretical and there are plenty of other scientists who would disagree with their conclusions. On the other hand, such apocalyptic notions are no longer the lunatic fringe. I am not qualified to judge whether the end of civilisation and the potential extinction of the human race (which would be the likely results of a 6 degree rise) is an odds on bet, 10-1 or 100-1, but even the latter sounds well worth insuring against.
So is it time to give up and pull the duvet over your head? I don't know, but if we all do that then disaster becomes assured. We have to assume that there is still time to change course, and work like crazy to make sure it happens. Did you ever see a disaster movie where things didn't look completely hopeless, then somehow come out right?
But if avoiding extinction relies on the current crop of politicians taking the hard decisions that need to be taken within the next ten years then I would bet my house on humans joining the Dodo - if only I could think of a way to collect the winnings.
Useful websites:
Comments