The world’s leading scientists issued a stark warning this month that we have a decade to get a handle on our carbon pollution or risk warming the world more than 1.5 degrees Celsius. Embedded within the pathways to keep things under control was a little-heralded finding: We need to rely on largely unproven technology to pull carbon out of the atmosphere.
With the clock ticking, a report released Wednesday by the largely federally-funded National Academy of Sciences lays out an ambitious research agenda for how the world could create and implement what are known as negative emissions technologies. And frankly, it shows we have a lot of work to do.
The idea of negative emissions is alluringly simple. It’s unlikely the world’s energy system will turn away from fossil fuels fast enough to avoid dangerous climate change, and there are other activities like agriculture that are tough to decarbonize. That means the world will have to deploy negative emissions technology to suck up excess carbon dioxide. We could, for example, use fancy machines that pull it out of the air, or plant forests and restore coastal wetlands that do the same thing naturally, or burn biomass for energy and capture the carbon emissions from burning it.
If the world is invested in the 2 degrees Celsius goal outlined in the Paris Agreement, emissions will have to peak by 2030 and start falling thereafter. The new report shows negative emissions will have to start scaling up in tandem with those declines and by midcentury, the world will have to sequester 10 gigatons of carbon annually. For comparison, human activities emitted about 36 gigatons of carbon in 2017. We sequestered basically nothing because it’s expensive and challenging to do at scale.
Of the technologies and techniques available, the new report notes that four are basically ready for prime time. It recommends that reforestation, shifts in forest management and agriculture, and the biomass burning and carbon capture idea (dubbed BECCS) can be scaled up now safely and at a reasonable cost. But the ramp up would need to be massive, and it still wouldn’t capture enough carbon out of the air.
To sequester a single gigaton of carbon using BECCS would require up to 106 million acres—the equivalent of the area of California—of cropland being turned over to growing biofuels. The scale and payoffs of unproven techniques is even more staggering. Turning all 13,000 miles of hardened U.S. shoreline to wetlands and mangroves that could sequester carbon would only pull 0.001 gigatons of carbon out of the atmosphere annually. The science fictional idea of speeding up the weathering certain types of rocks that can capture carbon from the air is even more unproven, though it could potentially generate wild returns.
To get a handle on these options, the team of scientists behind the report recommends a research program with hundreds of millions of dollars a year spread out across the federal government. We’re talking agencies that deal with coasts, crops, moonshot technologies, and more delving deep into what the future could look like as well as the risks we could face in implementing said future. That’s in addition to the work of, you know, implementing technologies that will reduce emissions at the source, something the Trump administration and the Republican-controlled Congress have been loathe to do.
“It’s clear we need to step on the emissions break, now,” Gernot Wagner, an economist at Harvard University, told Earther. “It’s equally clear that it’s high time the world took a serious look at carbon removal.”
Fixes that don’t stigmatize fossil fuels or upset the status quo seem to be a favorite among Republicans. We’ll see if the administration or Congress finds the report compelling enough to actually start down the inevitable path of humanity reshaping the Earth to ensure it remains habitable.