This paper reviews the case for alternative transport fuels in the context of greenhouse gas constraints. Fuel efficiency improvements and modal split shifts offer a potential to stabilize CO2 emissions from transportation. In the longer-term, however, alternative non-oil fuels will be needed to reduce emissions. Full fuel cycle CO2 emissions for various alternative transport fuels are presented. Carefully designed biofuel schemes, hydrogen and electric cars may be called upon to reduce greenhouse gas emissions; compressed natural gas and methanol are identified as transient fuels.
