350 in the bathtub

350 is a number that’s becoming a movement. The most important number on the planet. More and more people are coming to the realization that the relative measures of rates of greenhouse gas emissions really don’t matter – it’s how much is in the atmosphere that will drive global warming, which drives climate change, which drives climate disruption, which f’s up our civilization.

350 also makes things a bit simpler. For a long time negotiators and organizations, countries, regions making climate commitments have called for percentage reductions – 10% reductions by 2010 – reduced from what? Usually 1990 levels, but sometimes from emissions rates in 2000, or 2005, or 2006… sometimes the answer depended on what the emissions rates were like in a given baseline year. So it was getting confusing. And it also wasn’t that relevant.

We often get the dynamics of even the simplest systems confused. It’s just how our brains work. So to help, we often use the example of the bathtub. The facet is GHG emissions. The tub is the atmosphere. The drain are carbon “sinks” that remove carbon from the atmosphere. The highest the bathtub was ever full of water – over the 800,000 years that ice-core data shows was about 280 – that’s 280 parts per million. The lowest was about 180. Now 180 or 280 in a million might not sound like a lot, but it’s the difference between warm periods and ice ages. Since the industrial revolution, we’ve busted through that 280, and are sitting around 380. Scientists are calling for a return to 350 as a safe level for keeping our climate relatively stable, and hence limiting the disruption and destruction brought to our civilization.

Now think about what that means for the bathtub. We’re at 380. If we cut global emissions by 90% next year… we’ll still be moving in the wrong direction. At the end of the year, we’ll have more than 380 in the bathtub. Right now a lot of the strongest commitments out there, are talking about 20-30% cuts by 2020. Cuts in emissions. Think of the bathtub. The Sustainability Institute has developed a helpful simulator that allows you to play around with the faucet and see what it means in terms of emissions and atmospheric concentrations.

The colleges and universities that are building the ACUPCC have agreed to make plans for climate neutrality. That’s net-zero emissions. That’s turning the faucet off. (Recall if every institution in the world did that tomorrow, we’d still be at 380, and need to get carbon negative to get down to our safe 350). Now, the ACUPCC is still quite flexible, most schools, at least at first, will still create plans with much longer time horizons than we really need – but they will get started, with an end goal in mind that is necessary, not convenient. And I bet as they get going – and as everyone else gets going (the government, businesses, each of us) we’ll find we can pull those long range dates in and hit targets much more aggressively, at the pace we need to.

So 350 helps us get our heads around the scope of this challenge. The need for really dramatic action, quickly. It’s a rallying cry we need. It’s having a real impact in the COP negotiations going on in Poland right now. Check out www.350.org. Check out the 350 video. Rate it. Pass it on. Stay going.