Black carbon may be the second most important man-made warming agent after carbon dioxide.

BBC: Academics urge radical new approach to climate change

While methane is a cleaner source of energy than oil or coal when burnt, on its own it is an unusually powerful heat-trapping agent -- perhaps 20 times more potent than carbon dioxide.

CNN: Japan warms to 'fire ice' potential

If your employer participates, your travel management company or business travel agent can likely calculate how much it will cost to offset the carbon emissions from your flight.

BBC: Business travel gives back

He also uses a Canadian carbon-offset company, Offsetters.ca, which he gets through his travel agent.

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