Over the past few years the aviation industry has worked hard on how to replace fossil fuels by biofuels that would meet specific aviation criteria. But before implementing expensive biojet fuel manufacturing it seems legitimate to study global environmental impacts of a significant share of biofuels in transports by 2020. For that purpose, a method has been developed to study biofuels policies based on the life cycle methodology and adapted to the macro level to study indirect large scale effects on economic sectors.In this study, an economic general equilibrium model, has been coupled with an environmental Input/Output table in order to provide the amount of substances emitted in the environment by each economic sector in each region of the world when a biofuel policy is implemented. The economic model is also able to provide data for land use change that are then coupled with environmental factors, to obtain greenhouse gas emissions. Finally the GHG emissions from both the changes in economy and changes in land use are compared for two scenarios: one including the biofuel policy, the other assuming a business as usual situation.Results show that, even though the biofuel scenario is designed to mitigate climate change, it seems to cause more impacts. The inclusion of the emissions due to land use change in the global impacts enables to improve the completeness of this method. Nevertheless some improvement need to be achieved in order to adapt the method to the specificities of the aviation biofuels.