Without ‘negative emissions’ to help return atmospheric CO2 to 350 ppm, future generations could face costs that ‘may become too heavy to bear,’ paper says.
The only way to keep young people from inheriting a world reeling from catastrophic climate change is to reduce carbon dioxide emissions dramatically and immediately, according to a new paper. Not only that, but it’s also necessary to aggressively remove greenhouse gas that’s already accumulated.
“If rapid emission reductions are initiated soon, it is still possible that at least a large fraction of required CO2 extraction can be achieved via relatively natural agricultural and forestry practices with other benefits,” the authors wrote.
“On the other hand, if large fossil fuel emissions are allowed to continue, the scale and cost of industrial CO2 extraction, occurring in conjunction with a deteriorating climate with growing economic effects, may become unmanageable. Simply put, the burden placed on young people and future generations may become too heavy to bear.”
The study’s 12 authors, led by prominent climate scientist James Hansen, the former head of NASA’s Goddard Institute for Space Studies, call for bringing atmospheric carbon dioxide levels down to levels not recorded since the 1980s: 350 parts per million, a long standing goal of Hansen’s.
The level is now above 400 ppm, up more than 40 percent since before the Industrial Revolution. Many scientists reckon that 450 ppm is the safe limit to avoid the worst effects of global warming.
The paper, called “Young People’s Burden: Requirement of Negative CO2 Emissions,” was published Tuesday in the journal Earth System Dynamics Discussions.
It was written to support litigation by Hansen and a group of young people (including Hansen’s granddaughter) seeking to force more ambitious climate action. And it is the latest in a string of scientific analyses showing that nations are far from reining in dangerous warming, despite the imminent entry into force of a comprehensive treaty negotiated last year in Paris.
The Paris deal aims to limit warming to 1.5 degrees or 2 degrees Celsius, in line with the 450 ppm level. That would require bringing emissions to “net zero” sometime in the second half of this century through a swift clean energy transformation. Any CO2 spewed into the air—be it from a coal plant, an SUV or an airplane—would have to be completely offset, or “zeroed,” by increasing the growth of forests and other carbon sinks.
But according to the paper, even a net-zero world wouldn’t be enough to prevent burdening future generations with an impossible task.
To attain Hansen’s bolder goal, countries have to achieve “negative emissions,” by removing more accumulated CO2 from the atmosphere.
The paper lays out five possible scenarios. In the worst-case scenario, emissions continue to rise by at least 2 percent a year after 2015, and CO2 levels more than double to 864 ppm by 2100. To prevent that dire outcome, which assumes countries aren’t reducing their emissions to net zero, 768 ppm of CO2 would have to be sucked out of the atmosphere by that time.
That would be enormously expensive for future generations—perhaps impossible.
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