Delays raise emission halt urgency

The inventors of the idea of using wedges to represent efforts that will grow to prevent a billion tonnes of CO2 emissions per year over 50 years made a game out of it. However, University of California, Irvine's Steve Davis underlines that  our ongoing failure to properly put the idea into action is very serious. Credit: Carbon Mitigation Initiative/Princeton University

The inventors of the idea of using wedges to represent efforts that will grow to prevent a billion tonnes of CO2 emissions per year over 50 years made a game out of it. However, University of California, Irvine’s Steve Davis underlines that our ongoing failure to properly put the idea into action is very serious. Credit: Carbon Mitigation Initiative/Princeton University

We need to work towards completely cutting greenhouse gas emissions from energy generation for the goal of keeping global warming below 2°C to be realistic. So says Steve Davis at University of California, Irvine, who has updated a powerful method to make it easier to see what emission cuts are needed. That method originally just worked towards stopping emissions increasing, but Davis says that’s not enough today. “If you’ve been gaining weight and want to lose it, you don’t set a goal of eating just enough sweets to hold your weight constant for a few years, you set a goal of no sweets and set about losing weight right away,” Steve told me. “Why shouldn’t the same thing be true for carbon emissions?”

It’s hard to imagine how we can slow and stop emissions. In 2004, that drove scientists Stephen Pacala and Robert Socolow at Princeton University in New Jersey to come up with the idea of breaking the cuts needed into wedges. Each wedge is a unit of effort in stopping CO2 production, starting from a small beginning and becoming a massive impact. Over 50 years, each wedge of effort grows steadily from zero to a billion tons, or gigaton, of carbon emissions avoided per year. We can use the idea to decide how to cut out each wedge, assigning them to particular reduction efforts and technologies. Since their invention, wedges have been used to teach and make decisions about fighting climate change.

In their original study, the Princeton scientists just used the wedges  to bring our emissions to a stable level. At the time they found this would stop levels of the greenhouse gas in the air going above 500 parts per million (ppm). Reducing emissions from that level to zero would then have put a limit on climate change. However, accelerating emissions since their study have changed the starting point. Read the rest of this entry »