Land Clearing and the Biofuel Carbon Debt

Executive summary

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 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, 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.

Excerpts

Demand for alternatives to petroleum is increasing the production of biofuels from food crops such as corn, sugarcane, soybeans and palms. As a result, land in undisturbed ecosystems, especially in the Americas and Southeast Asia, is being converted to biofuel production and to crop production when agricultural land is diverted to biofuel production. Such land clearing may be further accelerated by lignocellulosic biofuels, which will add to the agricultural land base needed for biofuels unless biofuels are produced from crops grown on abandoned agricultural lands or from waste biomass.

Soils and plant biomass are the two largest biologically active stores of terrestrial carbon, together containing ~2.7 times more carbon than the atmosphere. Converting native habitats to cropland releases CO2 due to burning or microbial decomposition of organic carbon stored in plant biomass and soils. After a rapid release from fire used to clear land or from decomposition of leaves and fine roots, there is a prolonged period of GHG release as coarse roots and branches decay and as wood products decay or burn.

We call the amount of CO2 released during the first 50 years of this process the ‘carbon debt’ of land conversion. Over time, biofuels from converted land can repay this carbon debt if their production and combustion has net GHG emissions that are less than the life-cycle emissions of the fossil fuels they displace. Until the carbon debt is repaid, biofuels from converted lands have greater GHG impacts than the fossil fuels they displace.

Our analyses suggest that biofuels, if produced on converted land, could, for long periods of time, be much greater net emitters of greenhouse gases than the fossil fuels that they typically displace. All but two, sugarcane ethanol and soybean biodiesel on Cerrado, would generate greater GHG emissions for at least half a century, with several forms of biofuel production from land conversion doing so for centuries:

• The biofuel carbon debt from biofuels produced on converted Brazilian Cerrado is repaid in the least amount of time of the scenarios we examined. Sugarcane ethanol produced on Cerrado would take ~17 years to repay the biofuel carbon debt.
• Converting lowland tropical rainforest in Indonesia and Malaysia to palm biodiesel would result in a biofuel carbon debt of of CO2 that would take ~86 years to repay.
• Ethanol from corn produced on newly converted US Central grasslands results in a biofuel carbon debt repayment time of ~93 years.
• Converting lowland tropical rainforest in Indonesia and Malaysia to palm biodiesel would result in a biofuel carbon debt that would take ~86 years to repay.
• Converting tropical peatland rainforest to palm production incurs a similar biofuel carbon debt from vegetation, but the required drainage of peatland causes an additional sustained emission which would require ~420 years to repay.
  
• Soybean biodiesel produced on converted Amazonian rainforest would require ~320 years to repay compared with GHG emissions from petroleum diesel.

At least for current or developing biofuel technologies, any strategy to reduce GHG emissions that causes land conversion from native ecosystems to cropland is likely to be counterproductive.

Additional factors may influence biofuel impacts on GHG emissions, including the following:

• biofuel production can displace crops or pasture from current agricultural lands, indirectly causing GHG release via conversion of native habitat to cropland elsewhere.
• greater biofuel production might decrease overall energy prices, which could increase energy consumption and GHG release.

If biofuels are to help mitigate global climate change, our results suggest that they need to be produced with little reduction of the storehouses of organic carbon in the soils and vegetation of natural and managed ecosystems. Degraded and abandoned agricultural lands could be used to grow native perennials for biofuel production, which could spare the destruction of native ecosystems and reduce GHG emissions.

Biofuel production that causes land clearing and GHG release may be favored by landowners who receive payments for biofuels but not for carbon management. To accurately incorporate the costs of carbon emissions in market signals, emerging policy approaches to GHG emissions must be extended to the full life-cycle of biofuels including their net GHG emission or sequestration from land-use change. Moreover, it is important that international policy negotiations to extend the Kyoto Protocol beyond 2012 address emissions from land use change due to increased demand for biofuels.

Joseph Fargione¹ Jason Hill^2,3 David Tilman² Stephen Polasky^2,3 Peter Hawthorne^2
1The Nature Conservancy

²Department of Ecology, Evolution, and Behavior, University of Minnesota

³Department of Applied Economics, University of Minnesota

Published: Science, 07/02/08

Cap-and-trade in the U.S.

Sens. John McCain, Hillary Clinton and Barrack Obama have endorsed putting into place a cap-and-trade system to reduce carbon emissions though they differ on how that system should be structured.

Sens. Clinton and Obama both say they would cut emissions 80% by the year 2050. Sen. McCain aims for a lower 65% target. Sens. Clinton and Obama have rejected calls from utilities and other businesses to allocate the initial polluting rights based on a company’s current emissions. Instead, they want to auction off all the pollution rights. Sen. McCain is less clear on this point.

Moreover, the impact of such scheme on the economy may not be substantial. According to an analysis prepared by the U.S. Environmental Protection Agency (EPA), published on March 14 2008, the leading congressional proposal to control greenhouse-gas emissions could be implemented without significantly harming U.S. economic growth over the next two decades.

According to the analysis, if the U.S. were to implement the bill, GDP growth over 2010 – 2030 would be one percentage point less than in the absence of the bill. However, it projects that the proposal would cause electricity prices to increase by 44% by 2030.

The proposed bill would cap greenhouse-gas emissions from power plants, factories, oil refineries and other polluters. EPA also declared that, if it determines that greenhouse-gas emissions human health or well fare, it could have to impose costly new permitting requirements on a range of relatively small emitters of carbon dioxide, including large apartment buildings, schools, hospitals and retail stores.

Source: WSJ, 18/03/08

Preventing deforestation through carbon credits

Just two countries—Indonesia and Brazil—account for about ten per cent of the greenhouse gases released into the atmosphere. Neither possesses the type of heavy industry that can be found in the West, or for that matter in Russia or India. Still, only the United States and China are responsible for greater levels of emissions. That is because tropical forests in Indonesia and Brazil are disappearing with incredible speed. And when forests disappear, the earth loses one of its two essential carbon sponges (the other is the ocean).

Paying farmers or governments to prevent deforestation in countries like Indonesia would be one of the best investments the world could ever make. From both a political and an economic perspective, it would be easier and cheaper to reduce the rate of deforestation than to cut back significantly on air travel. It would also have a far greater impact on climate change and on social welfare in the developing world. Possessing rights to carbon would grant new power to farmers who, for the first time, would be paid to preserve their forests rather than destroy them.

The easiest way to finance such a plan would be to use carbon-trading allowances. Anything that prevents carbon dioxide from entering the atmosphere would have value that could be quantified and traded. Since undisturbed farmland has the same effect as not emitting carbon dioxide at all, people could create allowances by leaving their forests untouched or by planting new trees.

Source: The New Yorker, 25/02/08

Food miles and carbon footprint

It is a widely held assumption that the ecological impacts of transporting food—particularly on airplanes over great distances—are far more significant than if that food were grown locally. Yet the relationship between food miles and their carbon footprint is not nearly as clear as it might seem. In fact, many factors besides freight emissions influence the carbon footprint of a product.

Last year, a study of the carbon cost of the global wine trade found that it is actually more “green” for New Yorkers to drink wine from Bordeaux, which is shipped by sea, than wine from California, sent by truck. The study found that “the efficiencies of shipping drive a ‘green line’ all the way to Columbus, Ohio, the point where a wine from Bordeaux and Napa has the same carbon intensity.”

The environmental burden imposed by importing apples from New Zealand to Northern Europe or New York can be lower than if the apples were raised fifty miles away. New Zealand has more sunshine than in the U.K., which helps productivity. That means the yield of New Zealand apples far exceeds the yield of those grown in northern climates, so the energy required for farmers to grow the crop is correspondingly lower. It also helps that the electricity in New Zealand is mostly generated by renewable sources, none of which emit large amounts of CO₂.

Researchers at Lincoln University, in Christchurch, found that lamb raised in New Zealand and shipped eleven thousand miles by boat to England produced six hundred and eighty-eight kilograms of carbon-dioxide emissions per ton, about a fourth the amount produced by British lamb. In part, that is because pastures in New Zealand need far less fertilizer than most grazing land in Britain (or in many parts of the United States).

Similarly, importing beans from Uganda or Kenya—where the farms are small, tractor use is limited, and the fertilizer is almost always manure—tends to be more efficient than growing beans in Europe, with its reliance on energy-dependent irrigation systems.

The Natural Resources Department of Cranfield University, in England recently completed a study that examined the environmental costs of buying roses shipped to England from Holland and of those exported (and sent by air) from Kenya. In each case, the Department made a complete life-cycle analysis of twelve thousand rose stems for sale in February—in which all the variables, from seeds to store, were taken into consideration. It even multiplied the CO₂ emissions for the air-freighted Kenyan roses by a factor of nearly three, to account for the increased effect of burning fuel at a high altitude. Nonetheless, the carbon footprint of the roses from Holland—which are almost always grown in a heated greenhouse—was six times the footprint of those shipped from Kenya.

Source: The New Yorker, 25/02/08

EPOBIO report on the potential of micro- and macro-algae for industrial applications

The purpose of EPOBIO, a Science to Support Policy Consortium funded by the European Commission, is to realise the economic potential of sustainable resources – non-food bioproducts from agricultural and forestry feedstocks.

This final report from EPOBIO addresses emerging opportunities presented by phototrophic organisms of the aquatic environment. Of net primary production of biomass, it is generally accepted that 50% is terrestrial and 50% aquatic. Policies of governments have focussed almost exclusively on the use of land plants, with little consideration so far of the non-food applications and utility of macro- and microalgae and their products.

The limitations of agricultural land and the impacts of global climate change on agricultural productivity are factors of increasing relevance in the decisions that must be taken on land use for food, feed, chemicals and energy.

Various estimates for the production costs of algal biomass in photobioreactors range from US$ 30 – 70 kg, which is almost three orders of magnitude more expensive than waste biomass from conventional agriculture. The cost of producing algal biomass in raceway ponds, about US$ 10 kg, is about 2 orders of magnitude higher than that of biomass produced in conventional agriculture.

The major conclusion of the cost analysis is that the cultivation of algae solely for biofuels and CO2-mitigation is not cost-competitive by 1 – 2 orders of magnitude. Only if the algal biomass is a by-product of wastewater treatment systems, or high value compounds such as astaxanthin or β-carotene, commercially viable processes become feasible. However, this limits the scale of energy production and GHG abatement from algae by default to the amount of algal biomass produced to support the profitable applications, which is quite small.

Source: EPOBIO, Anders S Carlsson, Jan B van Beilen, Ralf Möller and David Clayton, 09/07

Hazards of wind power

A recent grid problem in Texas illustrates the potential shortfalls of wind power. The grid problem unfolded on Feb. 26 after a cold front blowing through West Texas temporarily lifted wind production.

When it subsided, wind speeds dropped and the productivity of wind turbines dropped by 80% from 1,700 to 300 megawatts. The problem was exacerbated by energy demand that was greater than forecast and by lower availability of some fossil-fuel units. The result was an electricity shortfall.

Shortages do more than degrade reliability; they push up prices. Wholesale power prices surged to $1,055 a megawatt hour in West Texas on Feb. 26, versus $299 elsewhere in the state.

To get the system back in balance, the grid operator declared an emergency and paid big customers to temporarily curtail electricity use. The problem illustrated the need for better wind forecasting tools.

Currently, the Electric Reliability Council of Texas, operator of the state’s high-voltage transmission system, accepts estimates of energy generators without second-guessing their accuracy. That is about to change. Texas is working on a method integrate more robust wind forecasts to make sure it doesn’t rely on resources that won’t materialize.

Source: WSJ, 06/03/08

Airline biofuel test

On February 24 2008, Virgin Atlantic Airlines flew a Boeing 747 from London to Amsterdam with one of the four engines burning a mixture of 80% jet fuel and 20% plant oil. The first commercial airline test of biofuel went without a hitch.

The fuel was produced by Imperium Renewables Inc., a four-year old Seattle manufacturer of biodiesel fuels. The company solved a problem many fuel experts had thought might be insurmountable – making a biofuel for jets that wouldn't freeze in low temperatures at flight altitude. Imperium came up with a process that yield fuel that won't freeze at minus 44 degrees Celsius.

The future for viable biofuels won't likely be coconuts and babassu nuts, whose oil were used for the test, however, because enough oil from those plants, which are both used in cosmetics, can't be produced to power the world airlines.

John Plaza, founder of Imperium, says its technology can make biofuels out of just about any renewable crop, and the substance that may hold the most promise is algae. Sewage treatment plans offer an ample source, and algae-produced fuel wouldn't use up food crops.

Source: WSJ, 26/02/08