There’s been a lot of talk recently about the sensitivity of climate systems – exactly how much will the planet warm if we double the concentration of CO2 in the atmosphere? What does that mean for climate policy?
Many of the articles, such as the recent write up in the Economist, talk about how we could potentially be over-preparing for climate disasters that may not come if we plan for 4oC and actually only end up with 1oC of global warming, which they argue will cost us too much money.
But here’s my problem with articles like that – I feel like they get halfway through the thought and don’t finish it. Yes, we may have lower climate sensitivity (although when you look at ocean warming as well as surface temperatures, it’s highly unlikely) and we may have ‘only’ 1oC or 2oC of global warming instead of a catastrophic 4oC or 6oC, but stabilisations at these lower temperatures will only happen if we stop burning carbon as well. Saying the climate may be less sensitive, therefore no worries let’s keep burning all the fossil fuels we can find as fast as possible is irresponsible.
Let’s say we’re lucky. Let’s say we ‘only’ get 2oC of global warming from all the carbon we’ve been spewing into the atmosphere over the last 160 years. None of those calculations count the carbon we’re going to burn today, tomorrow and into the future. These calculations only work if we stop burning carbon.
Also, the way people seem to be looking at the risk of 2oC is out of whack too. Look around you – look at the weird weather that’s been getting weirder every year with frightening acceleration. Hurricane Sandy, the persistent drought in the SW of the USA that is likely to lead to worse than Dust Bowl conditions, the wildfires in California and Colorado that are the worst ever – until the next wildfire season. The record breaking floods in the UK last summer, Germany and Alberta this summer, and in Australia in the intervening southern hemisphere summers. The Arctic ‘Death Spiral’ that is decades ahead of projections and the disturbing fact that last summer 98.6% of the surface of the Greenland ice sheet was melting.
All of these disasters were unprecedented. They’ve never happened before. They were all 1 in 100 year events or 1 in 200 year events, yet they keep happening every few years. This is happening with 0.8oC of warming. Think about what 2oC might look like. Are you terrified yet? Because you should be.
Here’s why: the Canadian International Council – a think tank based in Toronto released a graphic yesterday that shows very clearly exactly how we got ourselves into this mess and why betting the house on climate sensitivity is completely irresponsible.
Cast your minds back to science class with me – when you study thermodynamics, you learn the first law of thermodynamics which is that energy cannot be created or destroyed, just converted (which is how we’re all made of stardust!). Our planet is a closed system – the only things that have gotten in or out of the atmospheric blanket around the planet are the occasional space shuttle or meteor.
Have a look at that graph – we’ve taken all of that carbon that is really densely buried in the ground and we’ve burned it. Now remember the law of thermodynamics – it can’t be destroyed; only converted into other energy forms – so where has it gone? Into our atmosphere, changing the energy balance and warming our planet.
So while we might get lucky in our game of planetary roulette and land on 2oC instead of 4oC, or 6oC, the only way we’ve got a 50/50 chance of doing that is if we leave 80% of the remaining known fossil fuel reserves in the ground. Currently, we’re not even close to having climate policies that will do that in Canada or anywhere else in the world. Until we start taking large and systematic steps towards decarbonising our entire economy, bickering over whether we should be preparing for 3oC or 4oC of warming is like fighting over what size bucket to fight the fire with while the house burns down – it’s missing the point.