The carbon footprint of moving people

If you have ever been in an American airport or walked in any large American city you will have rapidly become aware of the massive amount of transportation that America devotes to moving people. There are cars, planes, railways, boats and buses trams and other forms of public transport. People often associate pollution and climate change solely with transportation. Of course there are other culprits but transportation is a particularly large source of greenhouse gas emissions and pollution in the United States, accounting as it does for 20% of US energy consumption and 5% of world energy consumption. Apart from sail vessels and horse drawn canal barges there are no forms of clean renewable energy for transportation. Continue reading