By Alison Crawford, CBC News

Former Liberal leader Stephane Dion waves before boarding his campaign plane parked next to Prime Minister Stephen Harper's campaign plane at Vancouver International Airport in September 2008. (Ryan Remiorz/Canadian Press)

Last year around this time, leaders of all three major political parties were hopscotching across Canada by airplane and bus.

And it's looking like they might well do so again, sometime this fall.

Together, Canada's travelling politicians pumped an awful lot of carbon dioxide into the air.

Much was made of how the very small-G green then-Liberal leader Stephane Dion hired an aged pollution-spewing Air Inuit plane to spirit him hither and yon.

Dion immediately pledged to offset his campaign's pollution by purchasing carbon credits. In the end, it cost the party roughly $50,000.

New Democrats paid $65,000 to cover their carbon emissions. Both the Liberals and NDP say they're committed to doing it all again.

The Conservatives did not offset their 2008 campaign carbon footprint.

When asked whether the party has plans to do so in any upcoming election, the prime minister's chief spokesperson Dimitri Soudas responded: "We don't want an election. That hasn't changed."