? A flight from Toronto to Rome produces 1.5 tonnes of carbon emissions per passenger, according to Air Canada's carbon calculator.
? CO2 emissions from aviation have increased a staggering 83 per cent since 1990.
? Air travel accounts for 12 per cent of CO2 emissions; road vehicles account for 75 per cent.
The greenhouse effect
? The burning of jet fuel releases water vapour, nitrous oxides, sulphate and soot, contributing to the formation of contrails and cirrus clouds that trap infrared radiation beneath them, heating the earth.
? The climate impact of aircraft is two to four times greater than the effect of their carbon dioxide emissions alone, because their emissions take place at high altitude, where they trigger chemical reactions that have a warming effect.
? Countries with national emissions targets under Kyoto, like Canada had until global warming laggard Stephen Harper came along, are only required to account for emissions from domestic flights, not international air traffic.
Fuel efficiency deficiencies
? We've pretty much maxed out on jet fuel efficiences, so unless there's some radical discovery in jet propulsion tomorrow, newer and better fuels aren't going to save us.
What's being done
? Not much. Some airlines are reducing carrying capacities for lighter takeoffs and landings to save fuel. But the EU is just now developing a plan to place limits on aviation emissions and, possibly, tax aviation fuel.
What you can do
? Vacation closer to home. A road trip from Toronto to the east coast, for example, produces less CO2 than jumping on a plane to Europe.
? Fly during the day. Daytime contrails offset the amount of heating on the earth's surface by blocking out some of the incoming light. Not so at night.
? Buy carbon credits. Airlines are giving passengers the opportunity to offset their carbon footprint when they fly, offering credits for purchase that end up funding tree-planting and other green projects.
?There are a few outfits putting carbon credits to eco good works.
?Green My Flight, our personal pick, funds only Environment Canada-approved projects. They're a bit more expensive, but are officially certified.
?Toronto-based CarbonZero funds windmills and retrofits for social housing.
?Toronto-based Zerofootprint, Air Canada's partner, is primarily involved in tree-planting projects.