Friday, 18 May 2007

A box of birds or a box of blades

I recently finished reading Tim 'Australian of the Year' Flannery's 'The Weather Makers: How Man Is Changing The Climate And What It Means For Life On Earth'. Couldn't help osscilating between wanting to head down to the corner store for a box of razorblades while reading it, or hoping beyond hope that maybe we actually avert laying waste to our planet to the extent that humanity could somehow survive beyond the 21st century. As one of life's natural pessimists, I can't help thinking that we're off to hell in a handcart, which a cynic might say is one way that helps me deal with childlessness, i.e. better not to have 'em as we're leaving nothing behind for them apart from a toxic and dessicated wasteland bereft of most living things.

Of course, it may not get that way for some decades to come, but as Flannery points out, we've already passed through a couple climatic 'magic gates' as it is: that is, leaps made by climate that mark the onset of "remarkable phenomena". We've apparently already been through two such magic gates in 1976 and 1998. The first occured when scientists drilled into a piece of coral from an isolated atoll in Kiribati and found that the detailed record of climate change contained within showed that the surface of the tropical Pacific Ocean has rarely dipped below 77 degrees Fahrenheit, when historically it usually sat around 66 degrees. This has caused huge shifts in the jet stream and tropical precipitation. The second occurred when the El Nino weather pattern became virtually permanent and coincided with fires that wiped out 25 million acres of land in South Asia, half of which was ancient rain forest. These major changes haven't corrected themselves and it's highly unlikely they ever will. It's only a matter of time before the next magic gate appears, which in turn may lead the tipping point that sends us completely over the edge. Flannery documents all the evidence to show that huge swathes of planetary flora and fauna have been lost to climate change. If we do our absolute utmost to reduce the amount of carbon we spew into the atmosphere though and stabilise global warming at only 5 degrees Fahrenheit above pre-industrial levels, then he reckons we may only lose one-tenth of all animal species on earth. That's the best case scenario.

In the worst-case scenario, we'll be reduced to a few breeding pairs at either Pole within a hundred years, according to the originator of the Gaia thesis, Sir James Lovelock. The latter has sometimes been portrayed in the mainstream Murdoch press as an extremist and a crank, but Flannery agrees with him: "Given the scale of the change confronting us, I think that there is abundant evidence to support Lovelock's idea that climate change may well, by destroying our cities, bring about the end of our civilisation."

Flannery posits three possible scenarios that may occur sometime within the next 10 to 50 years. Firstly, the Gulf Stream may collapse as a result of fresh water from melting ice accumulating the North Atlantic. This would cause another 'magic gate' when persistent drought would hit major agricultural areas with major plunges in temperature in northern Europe and America and major increases for South America, Australia and South Africa. As anybody who's read Jared Diamond's 'Collapse', Australia is already on a knife edge and will be the first to go once major climate changes take place. Just look at what's happening there right now. NZ is already starting to think seriously about how it would cope of an influx of climate refugees from across the Tasman.

Secondly, the Amazon rain forests could collapse very suddenly in a textbook example of a positive feedback loop, where increasing temperature leads directly to a vast increase in the amount of CO2 in the atmosphere. This would basically happen if Amazonian transpiration is shut down so that the rain forest ceases creating its own rain clouds. This would happen if increasing CO2 levels caused rain forest plants to keep their stomata closed for longer periods of time (because they can only absorb so much) and hence reduce the water vapour they transpire which in turns help create the rain clouds that keep the forests wet. A positive feedback loop. Reduced rainfall combined with a predicted increase in temperature in the Amazon basin of 10F will stress plants to the point that collapse of the forest will become inevitable.

Thirdly, the massive volumes of clathrates that sit on the beds of the oceans and that contain huge amounts of methane, could become overheated and release their greenhouse gases into the atmosphere. At present they're kept on the sea beds by the cold and the pressure of overlying water. But there are between 13,100 and 55,020 trillion cubic yards of the stuff, and if they're every released by a warming of the oceans, then it's goodnight nurse. Paleontologists reckon this is what happened to cause the biggest extinction event ever 245 millions years when nine out of ten species on earth became extinct during the Permo-Triassic period.

So, there we have it. Flannery does offer some hope and some solutions, but I'm too tired to write about that now. I'll save it for another post, but in the meantime, switch off all the lights and catch some public transport.