The reason I am so fascinated by the perils of global warming is not because I am an environmentalist (and I use that term very loosely), but because climate change – whether hot or cold – is a transformative, naturally occurring phenomena. And its forces are quite literally evolutionary.
This past week I have been studying the hypothesis that is Snowball Earth – way back in time, some 650 million years ago, when the Earth’s surface froze over in its entirety. A killer ice age that led to mass extinction.
In the 1960s Russian climatologist Mikhail Budyko drew up a mathematical theory. He developed a simple energy-balance climate model to investigate the effect of mass ice cover on global climate. He found that if ice sheets advanced far enough out of the polar regions, a feedback loop would result whereby the planet would remain trapped in ice forever – with no possibility of ever thawing out.
He dismissed his theory on the account that Snowball Earth did indeed melt sufficiently enough to enable life forms to continue. Without digging into much detail, his theory may have had some weight – it’s just we tend to overlook certain things, like the ability of our eco-system feedback mechanisms to find an escape route when all hope is gone.
And when the Earth does manage to self-correct, incredulous things happen. Major evolutionary shifts. According to fossil records, Snowball Earth may have triggered the evolution of multi-cellular life on our planet. Without the advent of this big freeze, we may not be here today.
This is why the current predicament we face – a 4°C global temperature rise by the end of the century which could see a catastrophic decline in food stocks and huge sea-level rises –doesn’t concern me perhaps as much as it should. I think if we are heading for disaster, it is a humanitarian disaster, but not a planetary disaster.
Mass extinction happens on Earth. It has happened before and it will happen again. We may be accelerating the next episode unnecessarily, but even so, at some point we are due a genetic apocalypse. And we will evolve. What into? Well that, dear reader, is what fascinates me about climate change.