Global temperatures may rise three-degree Celsius compared to preindustrial levels within 30 years unless we reduce carbon dioxide emissions significantly, according to a new paper led by Stanford Professor Rob Jackson (earth system science).

Jackson and his co-authors recommend stronger mitigation and adaptation policies to deal with climate change consequences of exceeding this “emission threshold.”

Negotiators from 194 countries are currently working to form a global pact limiting emissions to a level that would keep global temperatures from rising more than 2 degrees above pre-industrial levels. But that bar could be reached sooner than expected, Jackson said, despite actions to reduce emissions over the last decade.  Global emissions have grown at a rate of 2 percent annually for the past 15 years, he noted.

"We're speeding towards the two degree threshold," Jackson said.  "We could even see three degrees in a few decades if we don't step harder on the brakes."  

The study appeared in the National Academy of Engineering's Summer 2015 Issue of The Bridge, in a special feature dedicated to energy, the environment and climate change.

Rob Jackson is the Michelle and Kevin Douglas Provostial Professor and a senior fellow at the Stanford Woods Institute for the Environment and at the Precourt Institute for Energy.