A contentious topic that we've often seen batted around in policy circles and scientific forums over the past few months has concerned the long-term viability of biofuels — namely, is the trade-off inherent in converting ever larger tracts of forest to cropland worth it? We've expressed our own reservations about the merits of biofuels in the past but have remained somewhat open to the idea in the face of new research and ongoing developments taking place in the scientific and business communities. An article published in this week's issue of Science has helped rekindle our worries about the feasibility of a global biofuel energy market by claiming that no amount of biofuels can ever offset the environmental damage caused by the cutting down of forests to grow more crops.
Renton Righelato of the World Land Trust and Dominick Spracklen of the University of Leeds estimated that the initial cutting down of forests to plant more food crops, like corn and sugarcane, would release as much as 100 - 200 tons of carbon per hectare. They calculated that it would take between 50 and 100 years alone to compensate for these emissions by burning biofuels instead of fossil fuels — and that's assuming governments don't continue their rigorous regimen of deforestation. According to their best estimates, a 10% substitution of gasoline and diesel fuel would require 43% and 38% of current cropland alone in the United States and Europe, respectively. "We cannot afford that, in terms of climate change," said Righelato.
They also compared how much carbon could be stored by replanting forests with how much could be saved by consuming biofuels and found that reforestation would sequester 2 - 9 times as much carbon over the next 30 years than would be saved with biofuels (see chart above). Righelato and Spracklen thus argue that if the aim of switching to biofuels is to reduce the total amount of carbon emissions, "policy-makers may be better advised in the short term (30 years or so) to focus on increasing the efficiency of fossil fuel use, to conserve the existing forests and savannahs, and to restore natural forest and grassland habitats on cropland that is not needed for food."
While they concede that a biofuel derived from woody biomass could prove as effective as forests in sequestering carbon, they explain that — at this early stage of development — it is difficult to foresee exactly how much it will contribute to lowering emissions.
The researchers conclude that focusing on the conversion of large tracts of land to secondary forest would be most beneficial at this time and, thus, should be the primary aim of policymakers. Doing so would proffer a host of benefits — besides the obvious (reducing the net amount of carbon dioxide emissions), it would prevent further desertification, maintain biological diversity and provide regional climate regulation. For the long run, they go on to argue (to no one's surprise), we should make the development of carbon-free transport fuel technologies our main focus, a point we have consistently argued at TH.
Via ::Science: Carbon Mitigation by Biofuels or by Saving and Restoring Forests? (magazine, subs. required), ::New Scientist Environment: Forget biofuels - burn oil and plant forests instead (blog), ::Wired Science: Can't See the Forest for the Biofuels (blog)
See also: ::The Big, the Bad and the Biofuels, ::Italians Face Tough Call: Pasta or Biofuels?, ::Biofuel Plants Causing Air, Water and Soil Problems in Iowa
Images courtesy of World Land Trust and VerdeSam via flickr