Background on the safe level of atmospheric greenhouse gases

Below 350 parts per million carbon dioxide equivalent (ppm CO2-eq)

According to the 2007 assessment report by the Intergovernmental Panel on Climate Change (IPCC), developed countries need to reduce emissions 25-40% below 1990 levels by 2020, and 80-95% below 1990 levels by 2050, in order to stabilize atmospheric greenhouse gases to below 450 ppm CO2.  That concentration would only provide a 46% chance of avoiding catastrophic climate change.  Today it is widely believed that 350 ppm CO2 is the safe upper limit, and we are already dangerously above that, at 390 ppm. That is why we are quickly losing ice cover (Arctic summer sea ice could disappear in 2013!), and why methane plumes are bubbling out of warming sea beds.  We have at most a few years time window to still be able to reduce carbon and influence the climate system before powerful planetary amplifying mechanisms take the matter out of humanity's control, and bring on much stronger and unstoppable warming.  (More analysis on IPCC targets and odds here.)

The Massachusetts Democratic Party platform recently adopted a 350 ppm amendment at their State convention!  Now let's tell the MA Congresspeople (all are Democrats) to truly represent the people who they are supposed to represent.

Please click here to see a sample letter to send to Congress, to demand a real climate protection bill.

To see our more detailed analysis of ACESA/Markey-Waxman, read here.