Over on Charlie Stross’s latest blog post someone asked “Why would the temp keep going up for more than 10 years?” after a human extinction event.
This is a scary thing to read for a guy like me, because it means even in a nerdy-nerd context, people really don’t get how bad climate change will get.
Climate change isn’t an issue because we keep pumping out gases and so making the earth warmer. Climate change is an issue because there is a point – and people make Venus comparisons for this very reason – where the feedback cycle is non-negotiable.
Ice reflects sunlight. Less ice = more insolation = more change. Even better, less ice means more open sea surface, which is in general quite a good absorber and holder of heat energy. It may not get a lot warmer, but it gets bigger (sea level rise) and it gets darker (better at absorbing energy) and it holds more energy (more energetic weather events).
Permafrost and clathrates hold a lot of greenhouse gases in solid form. Scary amounts, really. They start melting, all those gases are up for grabs, and a lot of them will join the feedback cycle.
Asking why the temperature will keep going up is like asking why you keep getting warmer after you stop adding blankets. The blankets are still there! And in this case some of the blankets are electric blankets that are turned on, albeit on a relatively low setting.
The commitment to low temperature rise is premised on the idea that we stop putting blankets on and that the world around us, as it has done for billions of years, starts working on balancing blankets and open windows. We can’t guarantee that we haven’t already triggered a pile-on effect. We just have to hope that we’re divesting from…blankets…soon enough and fast enough to avoid the scenario where we burn all the way through the mattress.