2 studies conclude that biofuels are not so green after all
International Herald-Tribune, Feb. 7, 2008
Almost all biofuels used today cause more greenhouse gas emissions than conventional fuels if the pollution caused by producing these "green" fuels is taken into account, two studies published Thursday have concluded.
The benefits of biofuels have come under increasing attack in recent months as scientists have evaluated the global environmental cost of their production. The new studies, published by the journal Science, are likely to add to the controversy.
These studies for the first time take a comprehensive look at the emissions effects of the huge amount of land that is being converted to cropland globally to support biofuels development. The destruction of natural ecosystems - whether rain forest in the tropics or grasslands in
"When you take this into account, most of the biofuel that people are using or planning to use would probably increase greenhouse gasses substantially," said Timothy Searchinger, the lead author of one of the studies and a researcher on the environment and economics at
Plant-based fuels were originally billed as better than fossil fuels because the carbon released when they are burned is balanced by the carbon absorbed when the plants grow. But even that equation proved overly simplistic because the process of turning plants into fuel causes it own emissions - through refining and transport, for example.
The land-use issue makes the balance sheet far more problematic: The clearance of grassland releases 93 times the amount of greenhouse gas that would be saved by the fuel made annually on that land, said Joseph Fargione, the lead author of the other study and a scientist at the Nature Conservancy. "So for the next 93 years, you're making climate change worse, just at the time when we need to be bringing down carbon emissions."
The United Nations Intergovernmental Panel on Climate Change has said that the world has to reverse the increase of greenhouse gas emissions by 2020 to avert disastrous environmental consequences.
Together, the two studies offer sweeping conclusions: It doesn't matter if it is rain forest or scrub land that is cleared, although the former releases more emissions than the latter. Taken globally, the production of almost all biofuels resulted in such clearing, directly or indirectly, intentionally or not.
The European Union and a number of national governments have recently tried to address the land-use issue with proposals for regulations stipulating that imported biofuels cannot come from land that was previously rain forest, for example.
But even with such restrictions, Searchinger's study said, the purchase of biofuels in Europe and the
Fargione said that the dedication of so much cropland in the
International environmental groups and the United Nations responded cautiously to the studies, saying that biofuels could still be useful. "We don't want a total public backlash that would prevent us from getting the potential benefits," said Nicholas Nuttall, spokesman for the UN Environment Program.
"There was an unfortunate effort to dress up biofuels as the silver bullet of climate change," he said. "We fully believe that if biofuels are to be part of the solution rather than part of the problem, there urgently needs to be better sustainability criterion." He added that the United Nations had recently created a panel to study the evidence.
The EU has mandated that countries use 5.75 percent biofuel for transport by the end of 2008. In the
On Thursday, Syngenta, a major global agricultural conglomerate in
Bob Dineen, president of the Renewable Fuels Association in
"While it is important to analyze the climate-change consequences of differing energy strategies, we must all remember where we are today, how world demand for liquid fuels is growing, and what the realistic alternatives are to meet those growing demands," he said. "Biofuels like ethanol are the only tool readily available that can begin to address the challenges of energy security and environmental protection."
Most of the biofuel sold in
But the new studies suggested that when land use is taken into account few, if any biofuels, will be acceptable.
"This land-use problem is not just a secondary effect," Searchinger said. "It is major. The comparison with fossil fuels is going to be adverse for virtually all biofuels on cropland."
The only possible exception he could see for now, he said, was sugar cane grown in
The land-use debate started in the
Alex Kaat, a spokesman for the group, said: "If the whole point of biofuels directives was to reduce greenhouse gas emissions, we've found out that most biofuels are not really better than conventional fuels at that."
According to one study, titled: Use of US croplands for biofuels Increases Greenhouse Gases through Emissions from Land Use Change
"Most prior studies have found that substituting iofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. Using a worldwide agricultural model to estimate emissions from land use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on
According to a second study, titled: Land clearing and the Biofuel Carbon Debt:
"Increasing energy use, climate change, and carbon dioxide (CO2) emissions
from fossil fuels make switching to lowcarbon fuels a high priority. Biofuels are
a potential lowcarbon energy source, but whether biofuels offer carbon savings
depends on how they are produced. Converting rainforests, peatlands,
savannas, or grasslands to produce food-based biofuels in
Asia, and the
to 420 times more CO2 than the annual greenhouse gas (GHG) reductions
these biofuels provide by displacing fossil fuels. In contrast, 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."
Clearing raw land to produce biofuels actually contributes to global warming by emitting large amounts of greenhouse gases into the atmosphere, researchers have warned.
Carbon dioxide (CO2) emissions from new croplands carved into rainforests, savannas, wetlands or grasslands would easily surpass the overall amount of CO2 emissions reduced through the use of biofuels , according to a report in the Feb. 8 edition of Science.
"If you're trying to mitigate global warming, it simply does not make sense to convert land for biofuels production," said Joe Fargione, a founder of private environment protection agency the Nature Conservancy and co-author of the study.
"All the biofuels we use now cause habitat destruction, either directly or indirectly," he said.
"Global agriculture is already producing food for six billion people. Producing food-based biofuel, too, will require that still more land be converted to agriculture."
Converting land to grow corn, sugar cane or soy beans -- crops used in the production of biofuels -- creates a "biofuel carbon debt" by releasing 17 to 420 times as much CO2 into the atmosphere as the greenhouse gas reductions which the biofuels provide by displacing fossil fuels.
Carbon is stored in dead trees and plants as well as in the soil, and naturally seeps into the atmosphere in the form of CO2. Converting native habitats to cropland increases the release of CO2 into the air, the report said.
It would take years, and in some cases centuries, before biofuels derived from crops on converted land would lead to a net reduction of greenhouse gases, according to the report.
The researchers calculated that in
"We don't have proper incentives in place because landowners are rewarded for producing palm oil and other products but not rewarded for carbon management," said report co-author Stephen Polasky, an applied economics professor at
"This creates incentives for excessive land clearing and can result in large increases in carbon emissions."
An incentive for carbon sequestration or a penalty for carbon emissions is needed in order to slow CO2 emissions and environmental destruction, Polasky said.
The researchers noted that strong growth in the demand for corn-based ethanol in the
To address the ethanol demand, US farmers have stopped rotating corn crops with soy, leaving their Brazilian counterparts to produce more soybeans to meet rising global demand, resulting in further Amazon deforestation, they said.
The report stresses that certain biofuels do not contribute to global warming because they leave the natural ecosystem intact, and that obtaining biofuels from biomass waste or forestry products such as wood chips causes less harm to the environment and is the aim of several scientists.