Tuesday, April 30, 2013

Climate change: 400 parts per million

Atmospheric CO2 concentrations are expected to hit 400 parts per million in the next few days. 400 ppm is the level at which we would have had a good chance of avoiding the two degrees of global temperature rise considered by the international community to be unacceptably dangerous. Now we've blown through it, we are now committing to a much riskier future than we were before.

How risky? That depends on how high the CO2 level goes. At 450 ppm we have only a 50% chance of avoiding the drought, famine, flooding and widespread species extinction a two degree increase means. At 550 ppm, those consequences become highly likely. And that's the optimistic view from 2005; in 2013, now that we know more about positive feedback and tipping points, things look even bleaker.

We're spinning the wheel, and the safe outcomes are shrinking by the day. How long until our "leaders" act to protect us? Or are they too busy protecting the inflated asset values of those who have invested in the carbon bubble?