The next carbon capture tool could be new, improved grass

October 26, 2010 by Dan Krotz, Lawrence Berkeley National Laboratory
Miscanthus, a potential feedstock for biofuel, could pull double duty in the fight against climate change by sequestering carbon in the soil for thousands of years.

( -- A blade of grass destined to be converted into biofuel may join energy efficiency and other big-ticket strategies in the effort to reduce atmospheric carbon -- but not in the way that you might think.

In addition to offsetting fossil-fuel emissions, a potential bioenergy plant such as the grass Miscanthus could also snare carbon from the and trap it in the for millennia.

Sounds promising. But should scientists genetically engineer bioenergy to be better at ridding the atmosphere of the ? And can this strategy take place on the scale needed to mitigate climate change?

These questions are framed in a new analysis by Lawrence Berkeley National Laboratory scientist Christer Jansson and researchers from Oak Ridge National Laboratory. Their research, published in the October issue of , explores ways in which bioenergy crops can become a big player in the drive to rein in rising levels of atmospheric carbon dioxide.

The authors hope to get others thinking about engineering plants to not only produce biofuel, but to also sequester carbon.

“We want to encourage discussion and research on this topic,” says Jansson, a senior staff scientist in Berkeley Lab’s Earth Sciences Division and lead author of the analysis. “We need to explore the extent to which plants, and specifically genetically engineered plants, can reduce levels of atmospheric carbon.”

At the heart of the scientists’ analysis is the idea that bioenergy crops can fight climate change in two ways. There’s the obvious way, in which a plant’s cellulosic biomass is converted into a carbon-neutral transportation fuel that displaces fossil fuels. And the not-so obvious way: bioenergy crops also take in during photosynthesis and send a significant amount of the carbon to the soil via roots. Carbon from plant biomass can also be incorporated into soil as a type of charcoal called biochar. Either way, the captured carbon could be out of circulation for millennia.

At stake is the urgent need to make a dent in the nine gigatons of carbon that human activities emit into the atmosphere each year (one gigaton is one billion tons). Natural processes such as plant photosynthesis annually capture about three gigatons of carbon from the atmosphere.

“We could double that in the next several decades,” says Jansson. “By 2050, we could get to five or six gigatons of carbon removed from the atmosphere by plants, and I think a major part of that could come from bioenergy crops like grasses and trees. They could make a big contribution in sequestering carbon, but other strategies will have to be used.”

As Jansson explains, to increase the capacity for plants to act as carbon sinks, scientists need to continue to develop bioenergy crops that are efficient in harvesting light energy and using the energy to convert carbon dioxide to biomass. Bioenergy crops should also have a high capacity to send the carbon it captures to its roots, where it has the best chance to be stored in soil for thousands of years.

Fortunately, top bionergy crop candidates, such as Miscanthus, are already better-than-average carbon sinks. The large root systems in perennials such as grasses make them better at sequestering carbon in biomass and soil than annual .

But can bioenergy crops become even better? Jansson and colleagues outline several possibilities in their analysis. A plant’s canopy can be altered to enhance its efficiency at intercepting sunlight. Another approach accelerates a plant’s photoprotection mechanisms, which would improve its ability to use light. And a plant’s tolerances to various stresses could be improved without compromising yield.

A game-changing success, Jansson explains, could be the design of a bioenergy crop that can withstand drought and which utilizes brine, saline wastewater, or seawater for irrigation to avoid having to tap into freshwater supplies. Jansson suggests that genetic engineering can play a key role in introducing these traits into a plant.

“Bionergy crops are likely to be engineered anyway,” he says. “It makes sense to also consider enhancing their ability to withstand stress and sequester carbon. This analysis will hopefully guide research and prompt people to think in new ways about crops.”

Explore further: Genetically altered trees, plants could help counter global warming

More information: The article, “Phytosequestration: Carbon Biosequestration by Plants and the Prospects of Genetic Engineering” is published in the October issue of Bioscience

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2 / 5 (4) Oct 26, 2010
Is this anything like the contamination of genes from gmo canola into weeds that infest crops which the round up ready gene is supposed to help get rid of? My thoughts are, no matter what these loony scientists say, they are playing god and they are playing with fire, just like the end results of every other gmo plant or franken-monster organism which they've meddled with.

These nutbar scientists need to get some ethics, and avoid anything having to do with geo-engineering as they are going to destroy the planet in an effort to save it from the fraud concocted global warming the elites are trying to ram down our throats.
3 / 5 (2) Oct 27, 2010
Well, if you object to people playing 'god' then I suggest that if you get a fatal disease, that you don't take any man-made medicines or treatments to save your life, as clearly, your god wants it to end.
4.5 / 5 (2) Oct 27, 2010
My thoughts are, no matter what these loony scientists say, they are playing god and they are playing with fire

If you've flown in a plane, or seen a doctor, you've been a party to this "playing god" you speak of. It is human nature to push the boundaries. That is what we are. If you don't like it, fair enough, but realize that you cannot stop it. Unless you plan to change human nature? Maybe through gm?

Playing with fire? You are a super-complex biological organism that, according to your design, eventually breaks, existing on a giant rock flying around an even bigger ball of hydrogen undergoing nuclear reactions in a universe that exists, well shuck, were does our universe exist?
We are all playing with fire. Living is dangerous, so dangerous that you have 100% chance of dying. Don't let modern conveniences (playing god?) fool you.
not rated yet Oct 27, 2010
The lack of awareness of scientist working in large scale bio-fuel development regarding plant requirements for petro-chemical fertilizers and phosphates is remarkably incredible. It's clear that predicting peak oil is difficult because we continue to develop discoveries and new technology for recovering the 60%+ oil in our "exhausted wells." What people aren't aware of is that phosphates critical to plant production are even more limited than petroleum - an estimated peak 30 years, total exhaustion in 50 years. With 85% of human food crop production dependent on petro-chemical fertilizers, 95% dependent on petroleum to get from field to consumer, and with 100% of food crops require phosphate - the idea that bio-fuel doesn't compete with human food is ludicrous. Current logistics and spatial limitations suggest that only 3-5% of waste products can be used for biofuels. We need to focus on non-food competitive alternative energy sources like solar, wind, tide and wave.

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