For a long time scientists have been telling us that so long as we kept average rise in global temperature below 2C, which would happen if carbon in the atmosphere rose to 450 ppm, then there would be little danger of runaway global warming, but to be on the safe side we needed to keep ppm to 400. Even as late as 2010 it was reasonable to think that this could be achieved without difficulty. According to the Hubbert Curve oil production would peak between 2008 and 2014. As oil became scarcer and dearer, market forces, judiciously tweaked by governments, would bring renewables into their own.
In the last five years the situation has changed dramatically for three reasons.
1. It was thought that even in worst case scenarios the earliest we would breach 400 ppm would be 2015. In fact it was passed in May 2013.
2. A truly staggering, mind-blowing amount of oil has been discovered in the last five years. In 2012 scientists calculated that we could afford to burn another 565 gigatonnes of carbon. Currently the world is burning about 30 g a year. But according to the Tracker Initiative the oil firms already have at least 2,750 g in reserve, and much of this has already been sold on the futures markets.
3. And now there is fracking. Fracked gas is the worst of all greenhouse fuels because of the methane emissions. Methane is at least 72 times worse that CO2 over 20 years, just about the time we have left to save the planet.
The momentum that will take us past that 450 ppm is now almost unstoppable. We can only save ourselves, and millions of beautiful species that took millions of years to evolve, by making a resolutely determined all-out effort to get rid of fossil fuels. But even now there is still time. We can still make that tremendous effort. Let’s do it.