As the world’s junior ministers touch down from their holiday in Durban, The Independent today has perhaps the scariest story in human history. Perhaps. Russian scientists have observed vast plumes of methane rising in the Arctic Ocean.

Now, other than that, we can’t be sure what’s going on. I’m not a geologist, or oceanographer or expert in any of this. Perhaps there are other explanations. But we do know this: for a long time, we’ve been told that one of the potential positive feedback loops of climate change was the melting of things called methane hydrates (or methane clathrates). These vast stores of methane on the ocean floor will, according the the Clathrate Gun Hypothesis supported by people like former NASA climatologist James Hansen, melt as ocean temperatures rise. As they do, they will release vast quantities of methane into the atmosphere. Methane is a very powerful greenhouse gas.

There’s a reason it’s called runaway climate change.

Some scientists argue that it is exactly this process which kicked off the End Permian Mass Extinction 251 million years ago. The mother of all mass extinctions (known as “the great dying”), this led to 96% of all marine life being wiped out, and 70% of terrestrial vertibrae.

Now, I’m not saying that that’s what’s gonna happen. But it’s important to remember that when we toy with the climate, we are playing with scary stuff. As far as we know, despite today’s news, we can still prevent runaway climate change. But this is a terrifying reminder that time is running out…