Biofuels are among the many solutions being considered and developed as ways to alleviate the nation’s reliance on fossil fuels. Among the types considered are grasslands, ocean algae and forests. While they offer some benefits, there are drawbacks to each, depending upon the fuel source.
Biofuels often play a role in carbon sequestration. This is the process by which plants absorb carbon dioxide from the atmosphere and retain it in biomass. In essence, it is a natural way to lower atmospheric carbon dioxide by tying it up, as it were, in plants.
Depending upon the use of harvested timber, the carbon dioxide contained with the trees may be released or continued to remain in sequestration. Because certain tree species grow quickly, they have been considered as a possible biofuel source. However, doing so would eliminate their important role in carbon sequestration.
According to the U.S. Environmental Protection Agency (EPA), a pine plantation can sequester about one metric ton of carbon dioxide each year. Carbon dioxide is not the only greenhouse gas affected. Methane and nitrous oxide are also players. In addition, small amounts of sulfur dioxide are released when forests are used as biofuels.
The development of biofuels carries another unexpected twist that can have serious implications in terms of carbon sequestration. If the fuel source is corn-based ethanol rather than trees, this may motivate other countries to grow crops such as soybeans.
This action can, in turn, lead to deforestation in developing countries and exacerbate the problems with greenhouse gas emission. The EPA estimates that loss of tropical rainforests accounts for about 20 percent of the global carbon dioxide emissions each year. An incentive to increase deforestation can drive this figure even higher.
What this possible chain of events shows is that the solution to global warming is equally as complex as the phenomenon itself. Any development of alternative fuel sources must take into account the consequences to other aspects of the environment. The goal, after all, is to reduce greenhouse gas emissions, not shift the source to someplace else. It also underscores the need for a global approach that is acceptable in the long term.