Environmentalists Want to “Stick” It to Farmers

Jason Hill of the University of Minnesota’s Institute on the Environment wrote recently in the St. Paul Pioneer Press, asking why the Waxman-Markey climate change bill should treat agricultural emissions differently from energy and transportation emissions, with a “carrot-and-stick approach, one in which fossil fuels suffer the stick while agriculture feasts upon the carrot.” Hill’s primary objection to the bill is the amendments added by Rep. Collin Peterson (D-Minn.), which exempt agriculture and forestry from carbon caps but provide credits for carbon sequestration that farmers can trade on the market. They also would postpone implementation of the EPA’s analysis of international land use change.

Writes Hill, “Peterson’s amendment is essentially nothing more than a slick accounting trick, one meant to portray biofuels produced in this nation in a better light while making the carbon footprint of agriculture in developing countries look worse.”

This is a bizarre statement, turning even the theory of indirect land use change on its ear. The original calculation of indirect land use change put forward by Searchinger et al held that “when farmers use today’s good cropland to produce food, they help to avert greenhouse gasses from land use change.” Further, in the context of international negotiations for a climate change treaty to replace the Kyoto Protocol, the ILUC theory is clearly an attempt to shift accounting of carbon emissions in developing countries onto U.S. biofuels.

Calculations of land use change by current models are completely contradicted by agricultural trade and production numbers, making the models appear to be nothing more than accounting tricks. The model projections look nothing like real outcomes because they rely on several false premises and double count certain sources of emissions. The greatest fallacy of the ILUC theory is that worldwide agricultural productivity has already reached a natural limit and cannot respond to increased demand in any other way than clearing of rainforests. The main premise of the theory – that biofuels have been introduced into a static worldwide agricultural system and therefore are the primary cause of shifting agricultural production – is an assumption that can’t be supported by data.

Using USDA’s modest assumption for growth in yields of U.S. corn over the life of the Renewable Fuel Standard, a simple calculation shows that corn productivity can keep up with demand to produce the conventional biofuel portion of the RFS. This assumes continuation of 2016 to 2018 USDA projections for 2022 – constant total planted acreage of 90.5 million acres, increase of 75 million bushels per year for fuel ethanol, and increase of 1.8 bushel per acre per year yield improvement:

Overall harvested acreage for corn production is projected to remain stable due to continued yield productivity gains

In fact, USDA currently projects a corn yield of 159.5 bushels per acre for this year. And USDA projections from January 2009 show that inclusion of biofuels will stabilize land use, in terms of the acres planted to the eight major crops:

U.S. land planted to eight major crops.

Beyond this, and despite a report) that deforestation in Brazil increased in June, the deforestation rate in Brazil continues to decline. Responding to the Agence France-Presse report, Mongabay noted, “Deforestation in the Brazilian Amazon typically peaks during the June-August dry season when ranchers and farmers burn forest to clear land for development.”

A group of scholars – that includes Hill – recently called for a focus on real solutions to climate change. The world needs economic growth, energy and food. We should not premise our search for solutions on the false notion that these three necessities are in direct competition with each other.

Life Cycle Analysis, International Land Use Change and Uncertainty

Bruce Dale, University Distinguished Professor of Chemical Engineering at Michigan State University, shared this presentation that he gave during a webinar hosted by the North Central Bioeconomy Consortium. In it, he highlights the number of factors in Life Cycle Analysis and Indirect Land Use Change (ILUC) models that produce uncertainty – in other words, if the assumptions or data for these factors change, how much do the results change.

Dale is primarily examining the “carbon debt” concept that was introduced in the February 2008 Science papers by Searchinger and Fargione/Tilman. Dale argues that those papers failed to take into account how land converted to crop production might be managed. Dale recently submitted a paper to Environmental Science and Technology, testing the effect on land use change emissions if crop production is managed in a sustainable manner:

Sustainable cropping management practices (no-till and no-till plus cover crops) reduce the payback period to 2 years for the grassland conversion case and to 14 years for the forest conversion case. It is significant that no-till and cover crop practices also yield higher soil organic carbon (SOC) levels in corn fields derived from former grasslands or forests than the SOC levels that result if these grasslands or forests are allowed to continue undisturbed.”

Aside from assumptions about land management, life cycle analysis can be affected dramatically by changes in the amount and kinds of energy used in the biorefinery. American Fuels recently posted a note about some forthcoming research on the energy balance of biofuel production:

University of Nebraska at Lincoln researcher Kenneth Cassman concluded in a upcoming study that ethanol production has become more energy efficient.
‘Recent research conducted at the University of Nebraska clearly shows that estimates for the energy balance of corn-based ethanol are much more favorable – in fact two to three times more favorable, than previous estimates.'”

Since energy inputs are such a large factor in biofuel production, improvements in efficiency will significantly reduce the life cycle greenhouse gas emissions of biofuels when compared to gasoline.

How to Measure Land Use Change

Both the U.S. EPA and California’s Air Resources Board are currently considering how and whether to incorporate the indirect effects of U.S. biofuels production on carbon emissions from land use change in other parts of the world. The Renewable Fuel Standard passed by Congress in December 2007 requires inclusion of “significant emissions from land use changes” as part of the life cycle analysis of carbon emissions from biofuels. The Low Carbon Fuel Standard adopted by California also requires a life cycle analysis for fuels.

The issue of “indirect land use change” emissions was introduced early this year with the publication of papers in SciencExpress (see earlier post). Debate since the publication of those papers has focused on the lack of data to accompany the models and the assumptions inherent in the models. For instance, Searchinger and Fargione assumed that other countries would have to develop new cropland, primarily from sensitive ecosystems such as the rainforest, to replace the crops being used for biofuels in the United States. In a recent working paper, Roman Keeney and Thomas Hertel of Purdue University look at the possibility that increased crop yields would replace some of the crops being used for biofuels in the United States. They conclude that up to 30 percent of demand could be met through yield increases. Further, they show that Canada and Brazil – as the major grain trading partners for the United States – would be the countries to look at for any indirect land use change caused by U.S. biofuel production.

Keeney and Hertel do not calculate the impact that yield increases might also have in in Canada and Brazil, helping to meet demand. However, researchers at the University of Wisconsin do examine that possibility. Still, according to these researchers, the shift of land use does increase emissions and in the near term, demand is most likely to be met through expansion of land rather than increases in yield.

A group of researchers recently wrote to the California Air Resources Board, saying that until the uncertainties in the “indirect land use change” models had been thoroughly studied, they should not be calculated in the life cycle analysis required for biofuel producers in California. Other researchers responded that the effect certainly exists, so some calculation of it must be included under the law. They say that most calculations estimate that indirect land use change will double the greenhouse gas emissions attributable to biofuels.

The debate should not be whether land use change and cutting of rainforests releases carbon — it does. It should be whether indirect land use change can be reliably attributed to individual biofuel producers. Bruce Dale of Michigan State University put it this way during a field hearing of the Senate Agriculture Committee in Omaha, Neb., on Aug. 18:

It seems to me that making U.S. farmers responsible for land use decisions made by others is both unfair and a terrible precedent. Are we going to make every U.S. industry responsible for greenhouse gas generation by its competitors around the world?”

In other words, there are many factors that lead to deforestation in Brazil. As Iowa State University professors Eugene Takle and Don Hofstrand put it, “The conversion of native ecosystems to agricultural production started well before the emergence of the biofuels demand.”

It’s Carbon Payback Time

A recent study from researchers at the University of Wisconsin takes another look at the “carbon debt” models proposed by Searchinger and Fargione in ScienceXpress earlier this year. Searchinger and Fargione argued that biofuel development in the United States and Europe would lead to the destruction of rainforests and grassland in Brazil and other tropical climates, which would of course release massive amounts of carbon into the atmosphere (See earlier posting).

The new study takes into account some factors that other researchers criticized Fargione and Searchinger for ignoring. Bringing crop yields in the developing world up to the production level in the United States would increase biofuels’ carbon recycling benefits by up to 50 percent, according to the study authors. Further, if biofuels displace future production of oil from tar sands, their climate benefit will increase by another 25 percent. The researchers conclude that “future carbon payback times could be substantially shorter with increases in crop yields, changing petroleum sources and improved biofuel technology.”

Biofuels could have immediate benefits, the study authors conclude, if they are grown on degraded farm land. As another recent study from Stanford University shows, there are nearly 1 billion acres of abandoned farm land around the world. Some of this former agricultural land was once pasture grazed by cattle, and some was cropland that was abandoned for greener fields or because of changing needs. The study’s principle author calculates there is enough land in the United States to supply 9 percent of U.S. transportation energy, using current crop yield data.

UK Study Highlights Uncertainty in Calculating Indirect Land Use Emissions

Britain’s Renewable Fuels Agency this week released the Gallagher Review, a report on the indirect effects of biofuels production that was prompted by the Searchinger and Fargione studies published in Science earlier this year. (See this blog’s earlier post on the forthcoming study.)

The summary of the conclusions of the Gallagher Review include some very telling comments:

Quantification of GHG emissions from indirect land-use change requires subjective assumptions and contains considerable uncertainty.
“Current lifecycle analyses of GHG-effects fail to take account of indirect land-use change and avoided land use from co-products.
“Mechanisms do not yet exist to accurately measure, or to avoid, the effects of indirect land-use change from biofuels.”

Where does the uncertainty identified by the Gallagher Review in the Searchinger and Fargione models come from? Factors include the complex global nature of agricultural markets, the potential for a variety of biofuel feedstocks, production of co-products from the same feedstocks, and the prices of commodities.

According to the Gallagher Review, the model proposed by Searchinger cannot accurately predict future demand for commodities and how global markets will respond. The review notes that agricultural production of food and feed was already shifting from America and Europe to other parts of the world. U.S. and EU biofuel policies were a response to this shift intended to provide new markets for agricultural production.

Searchinger’s model also does not account for future productivity or increases in yield –- he assumes there will be no increase in yield. The model similarly does not take into account increases in productivity from biofuel production technology.

Further, Searchinger does not accurately account for uncertainties in the amount of greenhouse gas emissions that occur from land-use change. Professor Bruce Dale of Michigan State University has previously noted the difficulty in assessing emissions from land-use change. BIO’s 2006 study on Achieving Sustainable Production of Agricultural Biomass shows that adoption of no-till agriculture, which has been increasing, can reduce greenhouse gas emissions and even store additional carbon in soil, a fact that the Gallagher Review makes note of.

As a result, the Gallagher review disputes Searchinger’s calculation of a 167-year carbon debt for U.S. ethanol production, stating, “This review has been unable to definitively assess the accuracy of the Searchinger calculation for the GHG emissions arising from US maize ethanol.”

The studies conclusion for future policy is that biofuels have the potential to reduce greenhouse gas emissions and that policy should encourage innovation and new technologies that increase that potential.

Trying to Define the Indirect Land Use Issue

Michigan State University Professor of Chemical Engineering Bruce Dale recently sent a letter to colleagues interpreting the analyses by Searchinger et al. and Fargione et al. in Science. In the letter, Dale says, “The Searchinger and Fargione argument at its root is this: corn (and perhaps cellulosic) ethanol is not sustainable because it will divert land use for animal feed (over 70% of corn is fed to animals) to new lands that will release large amounts of greenhouse gases as they are cultivated.”

But Searchinger appears to go beyond accounting the carbon released from newly tilled soils in rainforests and grasslands. He includes as a cost the lost opportunity to store carbon in soils when they are converted from production of food and feed to production of biofuels.

In a published response by Timothy Searchinger to criticisms by Argonne National Lab’s Michael Wang and DOE’s Zia Haq, Searchinger says,

Prior studies all assign to biofuels the benefit of using land to take carbon out of the atmosphere by growing feedstocks, but fail to acknowledge that using land in this way has carbon costs, because it sacrifices other carbon benefits of land.”
“Even in the unlikely event that the world’s farmers could boost increases so high that the need for world cropland declines even with a higher population, each additional gallon of ethanol would still preclude some amount of cropland from reverting to forest or grassland.”

The DOE posted an official response to the Fargione study in which they question the assumption that Conservation Reserve Program land will be widely used for biofuel production.

Searchinger’s response and many other useful resources are published on a wiki discussion on the “Current Debate on Land Use” started by The Roundtable on Sustainable Biofuels. The wiki is open to the academic community for debate and discussion of the land use issue.

Scientists Respond to Carbon Debt Issue

Reaction to the ScienceXpress articles by Searchinger et al. and Tilman et al. has focused on the assumptions the teams of authors used in measuring greenhouse gas emissions from changes in land use. As Michigan State University Professor of Chemical Engineering Bruce Dale points out,

Both of these papers are modeling studies and are therefore completely dependent on the validity of the models themselves and also of the basic assumptions and data input to the models. If the models, assumptions and data are appropriate, then the predictions are useful, if not, the predictions may have little or no value.”

Dale is editor of Biofuels, Bioproducts & Biorefining (Biofpr) and head of the Biomass Conversion Research Laboratory at MSU. Michigan State University Bruce Dale Letter to Science

Michael Wang of Argonne National Laboratory and Zia Haq of the U.S. DOE provide a useful definition of “greenhouse gas emissions from land use change” in a published response to Searchinger.

Direct land use changes involve direct displacement of land for farming of the feedstocks needed for biofuel production. Indirect land use changes are those made to accommodate farming of food commodities in other places in order to maintain the global food supply and demand balance.”

Wang developed the GREET model used in the Searchinger analyis. Michael Wang, Zia Haq, Letter to Science

According to Wang and Haq, Searchinger et al. assume that use of corn in the United States for biofuel production will cause Brazil, China and India to convert forest and grassland to corn production to replace what they would have imported from the United States. Wang and Haq write that Searchinger’s assumption about indirect land use change is “seriously flawed” because it relies on data from the 1990s. Brazil and China have since that time adopted policies to prevent deforestation and conversion of grassland. Wang and Haq also criticize Searchinger for ignoring improvements in the use of land for growing crops and in technology to convert crops and crop residues as well as other biomass for biofuels.

The 25×25 coalition  notes that the ScienceXpress articles highlight the need for energy crops and production of cellulosic ethanol. They point to a study published in the Proceedings of the National Academies of Science that shows “that switchgrass grown for biofuel production produced 540 percent more energy than that needed to grow, harvest and process it into cellulosic ethanol.” 25×25 concludes, “Developing new sources of renewable fuels is a far better alternative to trying to squeeze petroleum from a depleting resource of fossil fuels at a demonstrably appalling environmental cost.”