Walking and cycling have long been considered the most environmentally sound methods of getting around. They still are but some environmentalists have argued that food production has become so fossil-fuel intensive that driving could be considered greener than walking (though the analysis has been debunked as flawed).
What of other, more obviously polluting, modes of transport? The data below gives an idea of how your carbon footprint might grow depending on how you make a journey. If you were to take an average domestic flight rather than a high-speed electric train, you'd be personally responsible for 29 times as much carbon dioxide.
The data also highlights how the UK government's plans to electrify parts of the rail network could cut emissions. Diesel trains are responsible for more greenhouse gases than electric trains, even taking into account Britain's carbon-heavy electricity production.
On the roads, next-generation hybrid and electric vehicles can help those of us behind the wheel to be that little bit greener. However, no journey is completely carbon free.