The amount of carbon dioxide in the atmosphere underwent one of its biggest single-year jumps ever in 2012, according to researchers at the National Oceanic Atmospheric Administration. Between the end of 2011 and the beginning of 2013, carbon dioxide levels increased by 2.67 parts per million — a rise topped only by the spike in 1998.
By comparison, global carbon levels averaged a yearly rise of just under 2 parts per million from 2000 to 2010, and increased by less than 1 part per million in the 1960s. The 2012 rise makes it that much more unlikely that global warming can be limited to the 2 degree Celsius threshold most scientist agree is the bare minimum necessary to avoid truly catastrophic levels of climate change.
There is a limited "budget" of carbon we can dump into the atmosphere while still maintaining a reasonable chance of staying under the 2 degree limit: 565 gigatons by 2050 to keep our chances at 75 percent, to be precise. At our current trends — and as 2012′s jump can attest — we're set to burn through that budget in 16 years.