Video: A Call for Negative Emissions

19 July 2017

We can reduce greenhouse-gas emissions, says a new peer-reviewed scientific study, but not enough to limit global warming to a level that won’t risk young people’s future. What we need is negative emissions -- a way to remove the CO2 already in the air.

Led by James Hansen, a professor at the Columbia University Earth Institute, the authors of the study estimate that today’s young people may have to spend up to 500 trillion euros (around U.S. $575 trillion) on technological solutions to extract carbon dioxide, if high emissions continue.

Bioenergy with carbon capture and storage is one technological solution holding some promise for creating a negative emissions state. Since crops and trees extract CO2 as they grow, using them as fuel -- and capturing the CO2, to be stored in geological formations under impermeable rock – could work. But the study authors caution that extraction technologies have "large risks and uncertain feasibility.”

The team does offer a ray of hope. Presuming we can rapidly phase down fossil fuel emissions, better agricultural and forestry practices could achieve most of the CO2 extraction needed to prevent the most dangerous consequences of climate change — more frequent and severe heat waves, storms, floods and droughts, as well as rising sea levels threatening millions of people living near the coast.

On average between 2000 and 2015, CO2 emissions rose at a rate of 2.6% per year. If they continue to grow at a reduced rate of 2% per year, we’d still need to somehow extract over 1,000 gigatonnes of carbon from the atmosphere by 2100. If we started reducing emissions at a rate of 6% per year beginning in 2021, however, that number would drop to around 150 gigatonnes of carbon – and two-thirds of that could be mitigated by improved agricultural and forestry practices alone.

The study, titled "Young People's Burden: Requirement of Negative CO2 Emissions," is part of the scientific basis for legal action in the case of Juliana v. United States -- a lawsuit filed by 21 young people against the U.S. government for violating their constitutional rights to life, liberty and property by failing to protect them against climate change.

To contact the author of this article, email

Powered by CR4, the Engineering Community

Discussion – 0 comments

By posting a comment you confirm that you have read and accept our Posting Rules and Terms of Use.
Engineering Newsletter Signup
Get the Engineering360
Stay up to date on:
Our flagship newsletter covers all the technologies engineers need for new product development across disciplines and industries.

Upcoming Events