Fewer biofuels, more green space: Climate action researcher calls for urgent shift

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Growing and harvesting bioenergy crops—corn for ethanol or trees to fuel power plants, for example—is a poor use of land, which is a precious resource in the fight against climate change, says a University of Michigan researcher.

Untampered green areas like forests and grasslands naturally sequester , and they are one of society's best hopes for quickly reducing the greenhouse gas in the atmosphere, says John DeCicco, research professor at the U-M Energy Institute.

DeCicco and William Schlesinger, president emeritus of the Cary Institute of Ecosystem Studies have authored an opinion piece in the current edition of Proceedings of the National Academy of Sciences.

The researchers call for policymakers, funding agencies, fellow academics and industry leaders to urgently shift their focus from bioenergy to what they call "terrestrial management," or TCM. That strategy emphasizes planting more trees and conserving more wild areas that feed on carbon dioxide.

"The world needs to rethink its priorities about how to use the biosphere given the urgency of the climate problem and the risks to biodiversity," DeCicco said.

The biosphere encompasses all life on Earth, and for climate protection, it particularly refers to trees, plants and the living carbon—microorganisms—in soils.

"Current policies advancing bioenergy contribute to the pressure to convert natural land into harvested forest or cropland," DeCicco said. "But high quality land is a limited resource. For reducing atmospheric CO2, the most efficient use of ecologically productive land is to leave it alone, or reforest it. Let it act as a natural, long-term carbon sink."

The new opinion piece expands on DeCicco's earlier findings that biofuels are not inherently carbon-neutral, as they are widely purported to be, and Schlesinger's long-time research as a leading ecologist and biogeochemist.

The assumption that bioenergy simply recycles carbon—which DeCicco and Schlesinger call a major accounting error—is built into the lifecycle assessments used for energy policy as well as the protocols for international carbon accounting. And it has fostered major R&D investments in biofuels, which, in turn, have been assigned a key role in many climate stabilization scenarios.

The core of that assumption is the idea that producing a biofuel and then burning it for energy moves a given amount of carbon from the biosphere to the atmosphere, and back again in an unending and stable cycle. That's in contrast to the current one-way flow of fossil-fuel carbon from the Earth to the atmosphere.

But here's where DeCicco sees a problem: For bioenergy to be actually carbon neutral, harvesting the biomass to produce it would have to greatly speed up the net flow of carbon from the atmosphere back into vegetation. Otherwise, many decades can pass before the "carbon debt" of excess carbon dioxide in the air is repaid by future plant growth.

"All currently commercial forms of bioenergy require land and risk carbon debts that last decades into the future. Given the urgency of the climate problem, it is puzzling why some parties find these excess near-term CO2 emissions acceptable," the researchers write.

In 2016, DeCicco published a study finding that just 37 percent—rather than 100 percent—of the carbon dioxide released from burning biofuels was balanced out by increased carbon uptake in crops over the first eight years of the U.S. biofuel mandate.

To reduce the concentration of carbon dioxide in the atmosphere, DeCicco and Schlesinger point out, requires increasing the rate at which trees and other plants remove it from the air. Although they don't rule out possible breakthroughs in algae or other futuristic bioenergy options, they say that for now the best biologically based carbon dioxide reduction strategy is to protect and restore carbon-rich natural ecosystems.

"By avoiding deforestation and by reforesting harvested areas, up to one-third of current carbon dioxide emissions from fossil fuels could be sequestered in the biosphere," the researchers write. "Terrestrial carbon management can keep carbon out of the atmosphere for many decades."

Explore further

Biofuels increase, rather than decrease, heat-trapping carbon dioxide emissions: study

More information: John M. DeCicco et al. Opinion: Reconsidering bioenergy given the urgency of climate protection, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073/pnas.1814120115
Citation: Fewer biofuels, more green space: Climate action researcher calls for urgent shift (2018, September 28) retrieved 18 July 2019 from https://phys.org/news/2018-09-biofuels-green-space-climate-action.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

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Sep 28, 2018
The way we currently extract biofuels from plant only uses about 10% of the total energy the plants used to turn carbon atoms into compounds. However, if plants were just used as a source of carbon atoms, then using the energy from alternate sources to create steam, there are well established mechanisms to reform those carbon atoms into a fuel that easily replaces gasoline. These are well known industrial processes. This allows the extraction of nearly all of the photosynthetic energy absorbed by plants to be turned into a form of fuel that be used by our existing multi-trillion dollar investment in gas stations and internal combustion engines in a completely carbon neutral way. Obviously the original carbon came from CO2 in the atmosphere, which would be replaced atom for atom by burning the fuel.

Sep 29, 2018
Yes indeed. We obviously can't afford to run our cars on food, which is what the current biofuel industry amounts to. There is far more cornstalk than corn, offering much greater potential for methanol, or even outright pyrolysis into synthetic gasoline, a process which can use anything from waste plastic to pig manure as feed stock.

Ethanol is for people, not cars.

Sep 29, 2018
Climate change articles should be in a political science category.

Sep 29, 2018
Climate change articles should be in a political science category.

Only those with ideological and partisan blinders really believe climate science is at political in any way.

The science behind climate change is just as much "science" as any other topic in biology, physics, chemistry, etc.

Sep 29, 2018
Only those with ideological and partisan blinders really believe climate science is at political in any way.

Climate science isn't, but the articles are.

The scientists can say anything they want - it's the press that makes it into politics.

Sep 29, 2018
Climate science is a political animal fueled by falsified data. Government grants depend on obtaining the desired research results. It was obvious from the very beginning that bio-fuels were counterproductive from a land uses perspective yet "Climate Science" was 101% behind them.

Sep 29, 2018
To start with the US temperature data is fictionalized due to the placement of many of the stations and the removal of others. The bias is slanted towards stations that need to be "adjusted" due to urbanized sites. Any time that data needs to be adjusted there is room for bias errors. If they really wanted to know the true temperatures there would be 10s of thousands of new stations sited in remote areas. But the use true temperatures does not fit into the master plan since they can only cause troubles justifying the planned outcome.

Sep 29, 2018
I just wanna say that Billy Meier wrote about this topic like 20 years ago...
...And the world is still overpopulated.

Sep 30, 2018
CO2 is not a poison, the 30% increase has only helped Earth. Our 400 ppm is very very low, compared to past Earth history with CO2 levels in the thousands.

Here's a way to reduce CO2 levels, cut off your head! hehe

doogsnova: Things are better now than ever before in history. Overpopulation is not an issue, as the many 70's studies claiming so have failed (claiming we should have been wiped out by it years ago). Nothing's perfect, but reality is still better than an imaginary perfect world that only exists in your mind.

Sep 30, 2018
The historical temperature data has been "adjusted" , to put it kindly, downwards in order to show more modern warming. Today's climate scientists must be direct descendants of the the medicine men of old, selling elixirs out of the back of wagons.

Sep 30, 2018
doogsnova - Exactly. We are still treating the symptoms of overpopulation - like climate change - rather than effectively managing global population to prevent them. Apparently the standards for prior population management tools like good old WAR and plagues simply aren't getting the job done any more. Hell, we can't even manage effective birth control with out enraging the ignorant zealots. Our fate is being sealed by our own collective willful ignorance (PC for STUPIDITY) and inaction.

Sep 30, 2018
Has anyone noticed that Physorg tends to post articles on controversial topics like climate change or evolution on the weekends? --as click generators? I'm trying to figure out if that's just my own bias.

Sep 30, 2018
I don't think that physorg publishes many articles on weekends, so I think you're mistaken. I think it just republishes the articles as they pop up and since most PR departments are closed on the weekends, not much appears at those times. This article was published on Friday.

Oct 01, 2018
This is roughly 2 weeks before the EU will introduce the new fuel designations giving information about biofuel content.

The way we currently extract biofuels from plant only uses about 10% of the total energy the plants used to turn carbon atoms into compounds.

It is a much smaller percentage with respect to total incoming light.

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