Learn how plants respond to higher atmospheric CO2 concentrations

How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic


More Bad Consequences of Biofuels
Volume 11, Number 29: 16 July 2008

In his misguided attempt to enlist Christianity to help promote the Intergovernmental Panel on Climate Change's anti-CO2 campaign, which is described in the September 2007 issue of Physics Today, England's Sir John Houghton claims we need "very large growth in renewable energy sources," among which he lists biomass in second place after solar. Already, however, it has been made abundantly clear that this "moral imperative" of his is not only not helpful, it is hurtful, as food prices around the world have soared in response to crops such as corn and sugar cane being sold for fuel -- as in ethanol -- instead of food.

But that is not the half of it, as we have indicated in a number of subsequent editorials that may be readily accessed by employing our website's search engine to seek out archived items containing the words "Sir John." And we here extend the list of bad consequences of this perverted policy even further, reviewing the findings of two groups of researchers published earlier this year in Science.

In an article entitled "Land Clearing and the Biofuel Carbon Debt," Fargione et al. (2008) explore what happens when non-agricultural lands are cleared for the growing of biofuel crops. In addition to the destruction of precious habitat needed to support what we could call "wild nature," this process releases huge amounts of CO2 to the atmosphere due to the burning and microbial decomposition of organic carbon stored in plant biomass and soils. And this initial "carbon debt" must be repaid before there is any net reduction in CO2 emissions from the use of the biofuel crops grown on the newly-cleared land.

So just how big can initial carbon debts be?

Fargione et al. make detailed calculations for six different scenarios of "native habitat conversion," which from the viewpoint of wild nature may be more properly described as native habitat destruction. These are: "Brazilian Amazon to soybean biodiesel, Brazilian Cerrado to soybean biodiesel, Brazilian Cerrado to surgarcane ethanol, Indonesian or Malaysian lowland tropical rainforest to palm biodiesel, Indonesian or Malaysian peatland tropical rainforest to palm biodiesel, and U.S. central grassland to corn ethanol." These conversions, in their words, would release "17 to 420 times more CO2 than the annual greenhouse gas reductions that these biofuels would provide by displacing fossil fuels." And they note that the huge carbon debts they produce "would not be repaid by the annual carbon repayments from biofuel production for decades or centuries."

Much the same conclusions are reached by Searchinger et al. (2008), who write that earlier studies of the benefits of substituting biofuels for gasoline "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." And by using a worldwide agricultural model to estimate emissions from such land-use changes, they find that "corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years," while "biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%."

In light of these several findings, it is clear, as concluded by Searchinger et al., that "when farmers use today's good cropland to produce food," which is what reason has always dictated they should do, "they help to avert [the release of] greenhouse gases from land-use change." To suggest anything different, as John Houghton and his climate-alarmist colleagues do when they promote the production of biofuels -- and to invoke religion as the basis for such actions -- is a perversion of both sound science and morality. Each domain needs the other to enable proper policy decisions to be made. In this particular case, sound science is required to determine what is moral, and morality is what we all hope would constitute the basis for our actions.

Sherwood, Keith and Craig Idso

References
Fargione, J., Hill, J., Tilman, D., Polasky, S. and Hawthorne, P. 2008. Land clearing and the biofuel carbon debt. Science 319: 1235-1238.

Searchinger, T., Heimlich, R., Houghton, R.A., Dong, F., Elobeid, A., Fabiosa, J., Tokgoz, S., Hayes, D. and Yu, T.-H. 2008. Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land-use change. Science 319: 1238-1240.