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New Studies Identify Change in Land Use Associated with Biofuel Production as Major Contributor of Greenhouse Gases, Far Offsetting Benefits of Most Current Biofuels

Two separate studies published in the current online edition of the journal Science identify land use change—the conversion of rainforests, peatlands, savannas, or grasslands to produce food-based biofuels or to replace existing cropland diverted to biofuel crop production—as a major source of increased carbon dioxide emissions, far offsetting the presumed greenhouse gas benefits of using most current biofuels.

The studies stress the importance of using biomass waste or biomass grown on non-agricultural lands as feedstock for biofuel production to avoid this problem.

Timothy Searchinger from Princeton and colleagues at Woods Hole Research Center and Iowa State University used a worldwide agricultural model to estimate emissions produced by the change in land use as farmers worldwide respond to higher prices and convert forest and grassland to new cropland. They concluded that corn-based ethanol, instead of producing a net 20% savings in greenhouse gases, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on US corn lands, increase emissions by 50%.

In their study, Joseph Fargione from the Nature Conservancy and colleagues at the University of Minnesota, calculated that land use conversion in Brazil, Southeast Asia, and the United States creates a ‘biofuel carbon debt’ by releasing 17 to 420 times more CO2 than the annual greenhouse gas (GHG) reductions these biofuels provide by displacing fossil fuels. In contrast, they said, biofuels made from waste biomass or from biomass grown on abandoned agricultural lands planted with perennials incur little or no carbon debt and offer immediate and sustained GHG advantages.

In the worst case Fargione and his colleagues examined, converting peatlands in Indonesia into palm oil plantations ran up a carbon debt that would take 423 years to pay off. The next worst was soybeans in the Amazon, at 319 years.

Searchinger et. al. note in their paper that “land use change emissions” refers to all of the carbon storage and ongoing sequestration that is foregone by devoting land to the production of biofuels. Using land to produce a biofuel feedstock forgoes some of that storage and ongoing sequestration, causing offsetting emissions in a variety of ways.

  • A forest or grassland can be directly converted to grow a biofuel such as corn, resulting in the direct loss of the carbon in the standing trees and grasses and a fair chunk of the carbon after plowing up the soils. Soils store major quantities of carbon in forests and grasslands.

  • The same land, if not devoted to biofuels, could continue to sequester carbon. For example, a young, growing forest will continue to sequester carbon as the forest grows for many years. This ongoing sequestration is lost if the land is converted to a biofuel for ethanol. (Although land converted to grow the biofuel, such as corn, will continue to sequester carbon, the typical biofuel analysis already takes account of that carbon.)

  • Both of these effects can occur indirectly. For example, if corn in the United States is diverted to ethanol production, grasslands or forest could be converted anywhere in the world to replace the corn. Complicating this analysis, these indirect effects can pass through many steps. For example, soybean land in the US can be planted in corn, and forest or grassland plowed up in Brazil to replace the soybeans.

In essence, under typical biofuel calculations, the carbon withdrawn from the atmosphere by growing the feedstock becomes a greenhouse gas credit. We call this credit a feedstock uptake credit, which we treat as part of the overall land use effect. But the world’s land already exists, and that land is for the most part removing carbon from the atmosphere each year and in most cases has stored substantial amounts of carbon for decades that may be lost if used to produce biofuels.

The proper focus must be on the net change in carbon removed from the atmosphere that is either stored by land or used to replace fossil fuels. (Replacing fossil fuels is a form of storage because the unneeded fossil fuel remains stored underground.) An accurate accounting must subtract the emissions from land use change from the feedstock uptake credit to produce a proper net estimate of the overall land use effect—the effect of using land to produce biofuels.




It would be interesting and informative, i think, if we could generate a world map of all 'abandoned agricultural lands planted with perennials' that create this so-called 'feedstock uptake credit' (greenhouse gas credit) that have the potential to be populated with the appropriate biomass. These techniques and approaches sound good in theory, but what is the overall potential when all areas are accounted for? Is there cost-effective access to each area? Does the ethanol produced in this way satisfy a significant portion of anticipated demand? What about the infrastructure to distribute?


Sorry, but I have to say it. WHAT A BUNCH OF CRAP. Their conclusions are idiotic because some of their assumptions are just plain moronic.

Hey everybody, I found the solution to Global Warming. Stop Farming. Idiots.



not quite sure whether your being sarcastic or not. But our countries desire to farm everything from an industrial model and lack of foresight for the damage doing this can cause is insane.

biofuel from agro-crops are bad, however, i'd say they are/were necessary to develop the demand and infrastructure for 2nd generation biofuels to come online.

Our legislative bills that provide support for bio-fuels should at this point have nothing to do with subsidizing agro-crops. If this country continues its increase with these 1st gen fuels points where our run-off concentrates like the gulf of mexico will be irrecoverable.

Our country needs to set an example and utilize our waste streams and how bout maybe getting these scientific panels to provide some real energy balance assessments prior to the development of an industry not after is starts to gain steam.

Lou Grinzo

Joseph: Please tell us why this study's "assumptions are just plain moronic". I'm asking this in all seriousness, and I'm not trying to call you out or be sarcastic.

This study is getting huge play in the media, and it could have a major impact on funding for further studies and even public policy. If it's as flawed as you say, please give us the details. I don't have free access to the paper (it's paid access), so I can't offer any commentary on the details.

Rafael Seidl

The only type of biofuel that can be produced both sustainably and cost-effectively at industrial scales from cellulosic wastes *today* is biogas. Second-generation bioethanol and biodiesel are still stuck in the laboratory and/or pilot projects.

Scrub out the H2S and CO2 and you have biomethane, which can be fed into the natural gas distribution grid. Methane is a great fuel for internal combustion engines and should become much more viable for mobile applications (i.e. cars) once adsorption tanks (ANG) can replace the heavy and expensive CNG tanks and, sharply reduce the pressure at which the gaseous fuel needs to be stored.

Physical (LNG) and chemical liquefaction (GTL, DME) are of course possible, but I'll wager keeping the fuel as close as possible to its natural state will prove to be more efficient.

Healthy Breeze

I think the challenge in getting intelligent use of this data is looking at where it holds up and where it doesn't. Context.

For instance, there's almost no crop that is going to absorb more CO2 than the rainforrest it replaced. However, nobody plants corn in rainforrest land. On the other hand, 8 foot tall miscanthus planted on marginal prairie would absorb more CO2, and have extensive enough roots that it might lock up more CO2 in total.

I am concerned that Indonesia and Brazil will be given more perverse incentives to deforrest by the biofuel movement. Can we have algal biodiesel already? The Southwest coast of Texas has lots of sunshine, salt water, and dirty industry to provide the CO2 already.


The studies are not very interesting, because you can offset this carbon debt very easily by using the original biomass (e.g. from a wood land) itself as a biofuel feedstock. Why burn this wood when you can use it to produce renewable energy?

This is already being done in the field and the development of modular pyrolysis plants makes it feasible on a larger scale.

Case closed (at least when it comes to the above ground biomass).

Check more here on second and third generation land use practises:

New land use techniques boost benefits of biofuels


There is no doubt, land use across the planet could be described as 'poor at best'.

First, everyone already knows corn is the worst feedstock for biofuel. Some soils are better 'sinks' than others. However, in the end, it can be no worse than NET.

"A new, young forest" That's a joke right, the last 'new forest' on the planet happened just after the last Ice Age. Any new 'growth' that you may observe is far eclipsed by the amount of natural as well as human derived deforestation. Their example only works if follow the very narrow parameters they set. Which one sequesters more CO2 the Boreal forest or the Rain forest?

Converting corn to ethanol is like reason #54 why the forest's are being clear cut. See: expanding over-population.

Basically while I was reading the report my brain was going; that's wrong, but what about ...., that just doesn't add up, Oh now that's a stretch.


I'm dubious about some of their assumptions - did they assume all forests were young? - which affects details of their conclusion. But the philosophy is still valid: the final affect of changes like an increase in biofuel ethanol from corn is complicated by the interactions in the global economy.

Brian Young

People need to wake up and consider why the destruction of primary forests, grasslands, wetlands, etc., is occurring.

It is NOT demand for biofuels. It is the increased demand for food, mainly caused by increased wealth and changing dietary habits of some of the most populous areas of the world. There is no doubt that biofuels represent a new demand which must be given its due looking forward, but biofuels are not “causing” the current mess we find ourselves.

Instead of trying to kill industries which are on the cutting edge of bringing positive change to the way we power our society, we need to look at the way one of the largest industries in the world, agriculture, continues to operate. Biofuels have turned the spotlight on world agricultural practices, and it is this potential as a major end user of ag products which the biofuel industry can leverage to demand changes to destructive farming practices.

The destruction of rainforests because of pressures from the ag industry started long before biofuels where ever seriously talked about and will continue long after. The majority of world governments care more about providing their citizens with cheap, subsidized food than saving forests in far away places. Without consumers demanding change there will be none.

Don't kill a new promising industry with the potential to make changes for the betterment of all. Work with it to fix the problems we've created over the last millennia.

Biofuels of today are 1st generation technology which is imperfect but represents a sea-change in our thinking about liquid fuels. These 1st generation technologies will continue to improve, and second and third generation fuels will develop by focusing on and solving the problems with the first generation. We will never get to the third generation unless the industry is allowed to exist and thrive. The third generation will never develop without consumer pressure to continually make improvements (and accept the change in economics associated with these improvements). This consumer pressure will force the successful biofuel companies to invest their profits in R&D to bring about the next generations of fuel. Persistent vigilance is required, but so is an acknowledgement that these changes take long periods of time and road bumps exist.

Those who represent big oil and those with economic incentives to resist a change to the establishment are going to destroy our dream, and they are pitting us against each other to accomplish this goal.

PS Those who post on this and all blogs should always provide their name. We need transparency if we want real dialogue. Just like we need to understand who funds the reports we depend on. I am in no way inferring that this particular report is biased. It is a general concern.

And yes, I do work in the biofuel industry.


Brian, please man, the amount of biofuels produced from crops grown on land that used to be pristine forests is marginal. The green lobby has tried to make it look as if all biofuels are destroying rainforests. Nothing is further from the truth. The vast bulk is grown on low carbon land.

So don't push this false message please. It is damaging the case of conservationists.

Moreover, don't forget that new land use techniques based on biochar actually stuff soils full of carbon.

Voice of Reason

The Renewable Fuels Standard, even taking into account distillers grains being produced, will end up consuming 3.5-4 billion bushels of corn a year. That's the corn from 23 million acres of farm land in the United States and perhaps a 1/3rd of the domestic corn harvest. The scale is certainly not trivial and there is no doubt that the decrease in corn exports from the US will cause people in other countries to clear more farmland.

Brian Young

Maybe I am confused, but I think we are saying the same thing.

I am in no way saying that there is not a problem with deforestation and land use. I am no way saying that conservationists and all green-thinking folks should not continue to push and demand change.

I am saying we need to look at the reality of the situation we are in and make changes from within.

Anyway, I'm not sure I understand your concern or maybe my point wasn't clear. I at least like the discussion.


i am also in the biofuel industry and i think corn sucks, granted i'm in 2nd gen but my lack of enthusiasm for corn and other industrialized agricultural crops stems from our need for healthy food not mono-cultured garbage.

i don't disagree we needed 1st gen fuels to develop and industry, i have considered it a necessary evil but it is time to move forward and not continue to increase the problems

i'm not actually convince it was a an evil we needed anyway biogas has been around for more than a century since the invention of the anaerobic digester.

we've all see back to the future right? well food waste has a dang high biogas yield which like was previously said bio-methane to CNG or LNG or burn it to generate renewable electricity

Rafael Seidl

@ HealthyBreeze -

I think you may be confusing two issues here. Yes, crops like miscanthus do absorb CO2 more quickly than a forest will. However, the whole point of planting the crop is to turn it into fuel that then gets burnt. Ideally, you end up with a perfectly closed loop in which no fossil hydrocarbons are used in e.g. the agriculture. Even then, you need to consider how long the cycle is (e.g. annual) and what fraction of the cycle the carbon spends in the atmosphere (guesstimate: 40-60%). Of course, such cycle considerations only refer to the integral carbon mass balance, not individual atoms.

By contrast, the carbon in a forest has a much longer cycle time of decades to centuries, depending on type and location. Growth is multi-annual but fairly consistent. A mature forest with stable total biomass will typically re-sequester the carbon mass released by the natural decay of dead wood within one year. So, figure the atmospheric fraction of the cycle amounts to just a few percent of total cycle duration. The fraction is higher for tropical rain forests, but so is the total carbon mass in the cycle per square acre.

A sudden release of carbon dioxide due to e.g. a forest fire means it remains in the atmosphere for decades, a timescale that may be long enough to have an impact on the climate. Worse, if the topsoil is lost to erosion after the fire, the forest cover will not return and the original emissions are just as permanent as if you had dug up coal and burnt that.

If you clear forest lands to make room for crops, the calculation becomes a little more involved. The new crops will sequester some atmospheric CO2 for part of the year. However, the total carbon mass in the new crop-based cycle will be substantially smaller than that in the original forest cycle. Therefore, the net effect is that the vast majority of the carbon sequestered by the forest cycle is permanently lost to the atmosphere.

Paleoclimatology suggests that the emergence of crop farming at the end of the last ice age coincided with a stabilization of the climate. Later on, vast tracts of forest were cleared in e.g. Europe to build ships and make room for fields and meadows. Spain is a prime example. What isn't really clear yet is how the climatic changes due to ice ages (which are probably caused by celestial mechanics) and those due to relatively rapid regional deforestation relate to one another in terms of scale and dynamics.


If is taken from the ground or grown as long as we burn it for our energy it will end up having some bad effects for the air and/or planet. I think instead of focusing on these relatively short term solutions like biofuels, we should pump as much research money as we can into battery technology and clean energy generation.

Patrick Mazza

I've been researching and writing on biofuels sustainability issues intensively for the past couple of years. I agree with Brian it is world agriculture as a whole we need to consider, not just biofuels. The land use displacement issue, to my mind, is the most complex. Here a small thought experiment is valuable. Consider the system with no biofuels - Would the disturbance of forest and grassland soils and carbon release never take place? There is no way to assert this, since growing demand for food, feed and fiber will push onto the same lands, though perhaps a few years later.

So then how do we preserve this carbon? Clearly we must make a profitable market for farm and forest carbon that is competitive with other uses. Meanwhile we should look at where bioenergy can promote bio-carbon sequestration by adding a value stream. That logically points to perennial grass and tree crops that sequester more in the roots than is released in bioenergy production and use. Putting together bioenergy and carbon revenue streams could enable production on lands that might be marginal for bioenergy alone.

Bottom line - High oil prices plus energy insecurity will continue to drive biofuels whether they are grown sustainably or not. We need policies such as low carbon fuel standards to drive toward sustainability.


Patrick, I agree: a global carbon price will force biofuel producers to utilize carbon-negative bioenergy systems. That is: bioenergy coupled to carbon sequestration (either via CCS or via biochar).

If oil is going any higher, biofuels will continue to be promoted because they offer crucial services that no other type of energy can deliver (namely cheap mobility).

So we should make the best of it. Discourage carbon-intensive biofuels by putting a price tag on carbon.


I figured that a state the size of Kansas could grown enough biomass in the form of corn stalks and wheat straw to provide 1/3 out our personal transportation fuel needs.

This is after they harvest the corn and wheat for food. We have plenty of farm land in the U.S. and we grow plenty of grain. Now, just use the grain STALKS for fuel and get on with it!


I really enjoy reading your blog, it always has great insight. But I am very frustrated with the fact that so few people are talking about presidential candidates and their thoughts on global warming. Now that it is down to just a few candidates I would think that this would be a bigger issue.

Live Earth just picked up this topic and put out an article ( http://www.liveearth.org/news.php ) live earth is also asking why the presidential candidates are not being solicited for their stance on the issue of the climate change. I just saw a poll on www.EarthLab.com that says people care a lot about what their next leader thinks of global warming. Does anyone know of another poll or other results about this subject?

Here is the page where I saw the EarthLab poll: http://www.earthlab.com/life.aspx. This is a pretty legit website; they are endorsed by Al Gore and the alliance for climate protection and they have a carbon footprint calculator. Does anyone have a strong opinion about this like I do? No matter what your political affiliation is or who you vote for this is an important issue for our environment, our economy and for homeland security.

Mark M

These studies amaze me, it seems when we compare biofuels we compare it to virgin native forest and of course it's co2 uptake is going to be less, we should only compare Biofuels to refined gasoline use. I live in Canada and I am familiar with the oil sands production, there is no way anyone can convince me that 1000's of acres of surface extraction, huge lakes of water effluent that can never be used again (creating a shortage for farmers) and many megawatts of power from coal to extract the oil is better than acres of biofuel growth (mixed with native plants and trees). Oil also needs to be refined to gasoline again using huge amounts of power.
Biofuels are 'part' of the mix and we have to start somewhere, cellulose production is of course the way to go when ready but it takes many years of design and construction to build Biofuel plants, we can impove them and their feedstock over time.
Most of our food is shipped using fuel, it's the price of gasoline that raises the price of food not the cost of corn, the farmers don't get the lion share.


Hillary's position on global warming and green energy can be found on her web site.


You may want to contribute to her campaign if you agree with her position.

Mark Delucchi

The basic point of these studies is correct: the development of biofuels can cause changes in land use that lead to relatively large emissions of carbon from soils and biomass. Indeed, this basic finding has been known, and quantified, for almost 20 years. The Searchinger et al. paper does do something relatively new: it uses an agricultural model to estimate global changes in production and consumption, the first step in estimating emissions due to land use change. (It also has a detailed treatment of changes in land use by type of ecosystem.) However, both papers suffer three serious general deficiencies, apart from whatever legitimate questions one might have about details of the modeling.

First, the studies do not have a complete conceptual treatment of what happens over time. Most importantly, they ignore the carbon sequestration that will tend to happen when the biofuel programs end and the land-use changes that occurred at the start of the program are reversed. Related to this, the explicit or implicit treatment of the timing of impacts in the studies – namely, that there is no distinction to be made between climate impacts that occur today and climate impacts that occur many decades from now – is not economically realistic.

Second, changes in land use affect much more than just carbon stocks in soils and biomass: they also affect albedo, hydrodynamics, the nitrogen cycle, dust emissions, and more. All of these omitted factors can have significant effects on climate, and not all of these effects are “bad” (i.e., warming). Without doing a comprehensive analysis of all of the climate-relevant effects of land-use change, it is not possible to make general statements about the effects of land-use change on climate.

Third, both studies add emissions from land-use change to emissions from the rest of the lifecycle of biofuels, and then make general statements about how considering land-use change affects total emissions from and the overall desirability of biofuels. However, there is as yet no remotely good model of emissions from the “rest” of the life cycle of biofuels, and as a result it is not possible to make any definitive statements about the overall impact of considering land-use change emissions in lifecycle analysis.

In sum, these studies highlight an important (and generally well known) effect of the development of biofuels, but leave out a great many important factors, and do not tell us anything definitive about the overall impact of biofuels on climate.

Mark Delucchi
Institute of Transportation Studies
University of California, Davis


==Mark Delucchi: Indeed, this basic (land use emissions) finding has been known, and quantified, for almost 20 years.==

If it's been quantified for so long, then why has Alex Farrell only recently been able to quantify?

(And the DOE/USDA practically assume it doesn't even exist)

Certainly your life cycle assessments have taken it into account. But as mentioned, Farrell now lists his corn impacts significantly higher than yours.

Additionally, Paul Cruzten, the Nobel Prize Winner for the Ozone hole theory, has mentioned that the nitrogen decomposition rate for N2O emissions is dramatically higher than previously thought.


The recently "Low Carbon Fuel Standard" report, coauthored by Alex Farrell and Daniel Sperling,
Seemed to express some frustration with the difficultly of factoring in land use impacts.


Additionally, I hate to sound rude.
But Nitrogen emissions, and the decreased Albedo caused by biofuels crops seem like they would only increase the harm caused by biofuels production.

As well as counting the emissions reduction when ENDING a biofuels production program seems to be a little flimsy of a qualifying part left out.
(Especially since simply reverting back to what was previously there 10 years later, wouldn't account for the compounded effect of warming feedbacks since then.)

And while models might not be perfect to date, it certainly does question the wisdom of rushing forward with ambitious biofuels mandates when there is a reasonable doubt that they could significantly cause more harm than good.

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