Biofuels, and especially biodiesel and ethanol, are often discussed as a big part of the solution to reducing greenhouse gas emissions from transportation. Since both ethanol and biodiesel come from agriculture products such as corn, sugar (ethanol), palm oil and rapeseed (biodiesel), there are no direct emissions from petroleum, gasoline or conventional diesel. The carbon cycle, in which biofuel crops absorb CO2 from the atmosphere that offsets emissions during fuel consumption, means that biofuels are essentially carbon neutral.
Biofuels may have an additional benefit: they could go hand-in-hand with sustainable development. In developing countries, sustainable economic development is usually a bigger concern that reducing GHG emissions. That's a real problem, because developing country emissions are growing more rapidly than those of developed countries. But could you create policies that achieve sustainable development with the secondary benefit of reducing GHG emissions?
That's the concept in WRI's Growing in the Greenhouse report. The report gives an overview of the "sustainable development policies and measures" (SD-PAMs) approach, and looks at four case studies in developing countries involving rural electrification (India), urban transport (China), ethanol (Brazil), and carbon capture and storage (South Africa).
Which brings us back to ethanol. There are legitimate concerns about the downsides of large-scale ethanol production, which sparked a spirited exchange on climatechangeaction.com. WRI analyst Rob Bradley, a lead author on Growing in the Greenhouse, responded to the issues, particularly those that affect Brazil. Among them:
- Deforestation to grow sugarcane
- Unfair labor practices
- Energy balances (how much energy do you get out of ethanol compared to the energy required to produce it?)
No doubt this conversation will continue. Ethanol is not a perfect solution to global warming, but all the current alternatives have downsides and tradeoffs.