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Tech + EngineeringTech & Engineering

Big Idea of 2015: Reversing Climate Change

ByAllison EckNOVA NextNOVA Next

The Paris Climate Agreement, signed just a few weeks ago, has set the stage for a 2016 that’s cooperative, action-oriented, and forward-thinking.

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It also marks the first time that world leaders have been able to table tired discussions about the veracity of climate change and instead focus on the reality of what’s in store. Our Earth is undergoing gradual and irreversible changes—but science could save us from passing the point of no return.

Unfortunately, the United Nations’

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31-page document didn’t once mention carbon capture and storage (CCS), a major stopgap in the climb toward carbon-free energy. If CCS equipment (originally intended to keep dirty coal plants in operation) is paired with biomass-burning power plants, we might be able to move beyond carbon-neutral solutions and actually take carbon out of the atmosphere. Called BECCS (Bio-Energy with Carbon Capture and Storage), such a system could, in effect, make up for some of humanity’s past emissions-related mistakes.

The post-harvest remains of corn stalks, known as corn stover, is a potential source of biomass.

Here’s NOVA Next editor Tim De Chant, reporting earlier this month:

The idea to combine bioenergy with CCS had emerged early in the 1990s, and the original goal was to make coal power stations carbon neutral. A little later in the decade, other scientists started exploring how to remove CO 2 directly from the atmosphere. It wasn’t until 2001, when Kenneth Möllersten, an engineer with the Swedish Energy Agency, and Jinyue Yan, a professor at the Swedish Royal Institute of Technology, put two and two together . Rather than push the limits of chemistry to capture CO 2 from the open air, they realized that we could let trees, grasses, and other plants do the hard work. All we’d need to do is collect and burn them, capture the CO 2 , and find somewhere to store it for a long, long time.

Burying the CO 2 from power plants deep underground has some inherent benefits. Unlike forests, which are also excellent long-term carbon sinks, stored CO 2 can’t easily be rereleased. Once buried, it isn’t likely to surface for thousands, perhaps millions, of years. Today, we have no way of guaranteeing that a forest will be left standing for that long. Plus, all plants eventually die and decay, releasing their carbon. Bioenergy with CCS is a best-of-both-worlds approach. With it, we can take advantage of plants’ natural ability to capture CO 2 and then use a proven technology to lock those emissions away.

Of course, scientists and policymakers face some obstacles in implementing BECCS. Biomass must consist of either organic waste or quickly-growing plants, and it has to be harvested and hauled before it’s combusted, which requires fossil fuels. There are economic disincentives, too. Read De Chant’s story for the full picture on the state of this innovative technology.

And for another take on carbon capture, check out Jori Lewis’s reporting for NOVA Next. Back in June, she wrote that locking carbon away for decades could be as simple as spreading biochar—a type of charcoal made from plant and animal waste that’s been heated by pyrolysis—on farm fields.

Photo credit: United Soybean Board/Flickr (CC BY)

Funding for NOVA Next is provided by the Eleanor and Howard Morgan Family Foundation.

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