Global warming can be confronting, it can be scary, and it has become politically divisive. But what if we stripped it back to a question of maths?
Climate change, after all, is basically a big maths problem, involving the quantity of carbon we wish to burn and the capacity of the atmosphere to contain it. The question is, how much more can we burn before we’re in trouble?
Australians may be forgiven for having a similar opinion—after all, the slightly-less-than-1-degree we’ve already raised the global average temperature allowed your ‘angry summer’. Averages hide extremes: all over the world we’re seeing government weather services having to add new colors to their charts. I’m not going to
cite all the endless records that have fallen across your continent in recent times, because I imagine you’re tired of hearing about them. Record rainfalls inundate some spot on the globe almost every week (because warm air holds more water vapor than cold, loading the dice for greater downpours). There’s only 20 percent as much ice in the summer Arctic as there was 40 years ago. That bears deeper consideration: we’ve taken one of the biggest physical features on earth, one of the things you can see about our planet from a great distance, and we’ve broken it. If that’s what one degree of warming will do, it’s actually quite daring to find out what two degrees will bring, using ‘daring’ in the sense of ‘stupid.’
But environmentalists and scientists lost that fight, and the world settled on the two-degree target—it’s essentially the only thing about climate change the world has settled on.
The next stage of our maths lesson requires finding out how much more carbon we could pour into the atmosphere and stay below two degrees. Here the answer is easier: a wide variety of computer models have converged on the figure of about 500 gigatons more. A rough number. And it comes with no guarantee that it will keep us below two degrees, just about an 80 percent chance. So, worse than Russian roulette, but it’s only our planet.
500 gigatons is a lot, but we’re producing more than 30 gigatons a year as a planet, and that number has been growing about 3 percent a year. Which gives us, oh, about 15 years before we go soaring past the two-degree threshold. If we are to avoid doing that, computer modeling shows that the world’s carbon emissions have to peak in 2015 and then come hurtling down.
Now let’s complicate matters. Let’s add in the new coal mines your carbon baro
ns, supported by government ministers Labor and Liberal, are planning on developing. In fact, let’s just take one set of mines, in the Galilee Valley. Those mines contain enough carbon to fill up 6 percent of the space between us and two degrees. One valley! There are plenty of other coal mines planned for Australia, not even mentioning shale oil and coal seam gas.
I want to be very clear – it’s very important that Australia has put a price on carbon, and very important that it not be overturned as a result of the next election. It’s a modest start that has had good effects in opening up the debate around the world, reduced domestic energy use and spurred development of renewable energy. Credit to Prime Minister Gillard, and more credit to the Greens’ Christine Milne who forced her hand. But, in mathematical terms, it’s even more important to rein in the huge expansion of Australia’s coal mines.
The maths doesn’t work from individual changes alone. It demands structural shifts on a massive scale. That’s why, in the USA, we’ve built a vast campaign on college campuses and in city governments demanding divestment from fossil fuel stocks. Because, if it’s wrong
asking you to consider taking your own money out of funds (your bank or your superannuation) which invest in fossil fuels. We’ll also be asking governments to stop putting your money into helping build more coal mine
s, coal trains and coal ports.
We’re already deep in a hole. And the first rule of holes is, when you’re in one stop digging. In this case, stop digging new coal mines.
This is an edited extract from Bill McKibben’s essay in The Monthly magazine of June 3, False Profits: doing the maths on Australia’s coal exports. McKibben is founder of 350.org