Consequences of ramping up biofuels
7 May 2013
MIT study looks at the unintended consequence of using biofuels as a source of energy.
The Massachusetts Institute of Technology (MIT) has found that land-use changes caused by a major ramp-up in biofuel crops could make some regions warmer.
“Because all actions have consequences, it’s important to consider that even well-intentioned actions can have unintended negative consequences,” said Willow Hallgren, the lead author of the study and a research associate at MIT’s Joint Program on the Science and Policy of Global Change.
“It’s easy to look at a new, cleaner energy source, see how it will directly improve the climate, and stop there without ever considering all the ramifications. But when attempting to mitigate climate change, there’s more to consider than simply substituting out fossil fuels for a cleaner source of energy.”
Emphasising changes not only globally, but also regionally, is vitally important
Hallgren and her colleagues explored some of those consequences in considering two scenarios: one where more forests are cleared to grow biofuel crops, and one where forests are maintained and cropland productivity is intensified through the use of fertilizers and irrigation.
In both cases, the researchers found that at a global scale, greenhouse-gas emissions increase — in the form of more carbon dioxide when CO2-absorbing forests are cut, and in the form of more nitrous oxide from fertilizers when land use is intensified.
But this global warming is counterbalanced when the additional cropland reflects more sunlight, causing some cooling. Additionally, an increase in biofuels would replace some fossil fuel-based energy sources, further countering the warming.
While the effects of large-scale expansion of biofuels seem to cancel each other out globally, the study does point to significant regional impacts- in some cases, far from where the biofuel crops are grown.
“Emphasising changes not only globally, but also regionally, is vitally important when considering the impacts of future energy sources,” Hallgren says. “We’ve found the greatest impacts occur at a regional level.”
While Hallgren focused specifically on the climate implications of expanded use of biofuels, she admits there are many other possible consequences, such as impacts on food supplies and prices.
