The Carbon Budget: An Explainer

What is the Carbon Budget?

The carbon budget is the amount of carbon dioxide the planet can release into the atmosphere before global temperatures raise to 2 degrees Celsius above pre-industrial levels (i.e., the year 1870). The 2015 Paris Climate Agreement set this goal of 2 degrees, but also expressed that the preferred goal should be to limit global warming to 1.5 degrees to prevent very undesirable changes to our climate. New research determines that our total carbon budget, beginning in the year 1870, is about 2.75 trillion tons of CO2. This is the total amount the planet can release and still stay below 1.5 degrees of warming. By 2015, we had already released just over 2 billion tons of CO2. And the planet’s temperature had increased by 0.9 degrees. The world’s annual CO2 emissions is about 40 billion tons as of now. So we have about 750 billion tons of CO2 left to release in our carbon budget, which will last about 20 years at our current rate of emissions.

What Needs to be Done

To end our CO2 emissions sustainably and stay within our carbon budget, researchers say we should cut annual emissions by about 1.1 billion tons of CO2, or 4-6%, per year. Fortunately, the rapid increase in annual carbon emissions has slowed significant and reached a plateau. We still need to improve a lot in a short amount of time to meet keep global warming below 1.5 degrees, however. The only other option is to develop new “carbon capture” technologies to take CO2 out of the atmosphere. These innovations are still a long way off.