Global Warming and the Minefield of Unintended Consequences

Dubner and Levitt recently wrote a column discussing the unintended consequences of legislation intended to help the neediest segments of society.

Few movements for change have met with as many unintended consequences as the efforts, both in the public and private sector, to combat global warming. Take biofuels (another topic Dubner has addressed here and here). Hailed as the darling of the alternative fuel market, this new energy source, led by the most popular form, ethanol, was declared the solution to burning fossil fuels in 2006. It has since been embraced by companies from luxury car makers to airlines. To meet the growing demand for ethanol, U.S. farmers and agribusiness firms invested millions in growing corn (a move that has already come back to bite them financially). Biofuels have become such a staple of international plans to combat climate change, reports the Times, that governments are even legislating and subsidizing their use:

The EU has mandated that countries use 5.75 percent biofuel for transport by the end of 2008. In the United States, a proposed energy package would require that 15 percent of all transport fuels be made from biofuel by 2022. To reach these goals, biofuels production is heavily subsidized at many levels on both continents.

Fantastic! A worldwide movement to cut emissions and halt what a growing number of scientists call a massive global crisis. Except it all hit a roadblock last week, when two newly-released studies reported that the net environmental effect of using biofuels may be even more harmful than burning the gasoline they were created to replace.

The first study, led by Princeton University environment and economics researcher Timothy Searchinger, found that replacing fossil fuels with corn-based ethanol could actually double greenhouse gas emissions for the next thirty years. As Scientific American writer David Biello explains it:

“Prior analyses made an accounting error,” says [Searchinger]. … “There is a huge imbalance between the carbon lost by plowing up a hectare [2.47 acres] of forest or grassland from the benefit you get from biofuels.”

Growing plants store carbon in their roots, shoots and leaves. As a result, the world’s plants and the soil in which they grow contain nearly three times as much carbon as the entire atmosphere. …

By turning crops such as corn, sugarcane and palm oil into biofuels – whether ethanol, biodiesel, or something else – proponents hope to reap the benefits of the carbon soaked up as the plants grow to offset the carbon dioxide (CO2) emitted when the resulting fuel is burned. But whether biofuels emit more or less CO2 than gasoline depends on what the land they were grown on was previously used for…

The second study, led by Joseph Fargione, a scientist at the Nature Conservancy, found that by switching to biofuels, we could essentially be worsening climate change for the next 93 years, in that “[t]he clearance of grassland releases 93 times the amount of greenhouse gas that would be saved by the fuel made annually on that land,” according to the Times. Not to mention the fact that, by switching to growing corn, U.S. farmers have turned away from growing other crops, such as soy. As a result, Fargione told the Times, “‘Brazilian farmers are planting more of the world’s soybeans – and they’re deforesting the Amazon to do it.'”

So in a matter of days, biofuels go from a celebrated fossil fuels alternative to a rainforest-killing disaster, with scientists already calling for government reform on biofuel policies. If anything, this provides a window into how little we actually know about this issue, and the wide lengths left to go in reaching a viable solution.