Cultiver des biocarburants augmente les émissions de gaz à effet de serre

Cultiver des biocarburants sur des terrains qui étaient auparavant des forêts ou des prairies génère des émissions de gaz à effet de serre non prévues et augmente donc leurs coûts, ce qui suscite des craintes sur l’objectif ambitieux en matière de biocarburants, révèle une nouvelle étude de Tim Searchinger du German Marshall Fund.

The February study’s findings disprove prior research claiming that substituting biofuels for gasoline would reduce greenhouse gases by revealing that it overlook one crucial factor: the fact that the conversion of forest and grassland to cropland in order to replace the grain diverted to biofuels produces additional carbon emissions. 

Despite this negative effect, the author criticises the EU for not allowing the use of biofuels produced on land converted for crops to contribute to their target of supplying 10% of transport fuel from biofuels by 2020. This safeguard would not solve the problem but instead require that biofuel producers use existing crops, he argues. 

« Most analyses have counted the carbon benefits of using land for biofuels, but not the carbon post, » Searchinger writes. The author also criticises the EU for having set the target of producing 10% of transport fuels from biofuels by 2020 in the first place.

Moreover, the new study found that corn-based ethanol nearly doubles greenhouse emissions over 30 years and indeed increases them for 167 years, instead of producing a 20% saving as previous studies suggested. 

Another recent study shows that soybeans are meant to have a similar effect to corn ethanol, Searchinger reveals. Thus he author suggests a shift towards greater use of soybeans. 

The article concludes by endorsing the particular value of making biofuels from municipal, industrial or agricultural waste products.