The world's population is forecast to rise to 9 billion by 2050. As I wrote nearly three years ago, one challenge will be to feed these extra people, but a bigger challenge will perhaps be to feed these extra 3 billion people without destroying forests and wildlands to grow the additional food. With the growth of biofuels – using the land to grow fuel as well as food – that challenge will be even greater. And increasingly, studies are showing that higher prices and subsidies of biofuels worldwide have resulted in forests and wildlands being destroyed to grow fuel, while actually increasing, not decreasing, greenhouse emissions.
From a recent study in the journal Science Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change:
Most prior studies have found that substituting biofuels 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. By 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 U.S. corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products.
How is it that the old studies didn't report this? For years, studies have attempted to determine if the energy obtained from biofuels was greater or less that the energy required to grow and process them. Some researchers concluded that biofuels were greener than fossil fuels; others disagreed. But as Time Magazine recently reported, all these studies – both pro and anti-biofuels – seem to have ignored one major factor:
There was just one flaw in the calculation: the studies all credited fuel crops for sequestering carbon, but no one checked whether the crops would ultimately replace vegetation and soils that sucked up even more carbon. It was as if the science world assumed biofuels would be grown in parking lots. The deforestation of Indonesia has shown that's not the case. It turns out that the carbon lost when wilderness is razed overwhelms the gains from cleaner-burning fuels.
See the picture on the right from the Time article, that perfectly illustrates what is happening. This all used to be Brazilian rain forest, but now only a sliver of wild forest is left. That can't be good. I’m not really in a position to evaluate the green (or otherwise) credentials of biofuels in detail, and in any case the answers you get depend on what assumptions you start off with and which biofuels you are talking about. But it seems clear to me that it makes no sense to sacrifice wild land to grow fuel when we need to feed an increasing population and maintain our wild land. It was obvious this would result in an undesirable increase in monocultures, fertilizer run-off, higher food costs etc, even before we considered the additional cost of releasing more carbon into the atmosphere as the land is cleared. Studies like these recent ones just make the case against biofuels even stronger.
We’re only producing a small amount of our fuel requirements now via biofuels, but government subsidies and regulations are set to increase this considerably in the future. Fortunately the US congress has acted quickly to remove subsidies for biofuels as well as to rescind future requirements for increased biofuel production. Just kidding. The subsidies and requirements to increase biofuel production are still in place.