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Flying is one of the most climate-damaging things we can choose to do – but there is a way to lessen the impact of your flight: fly by day, never at night. Better yet, take it a step further: Make like a goose and avoid winter flying. Indulge your far-flung travel fantasies in the summer.

Jet engines spew out tonnes of carbon dioxide, but that's not the only way they contribute to climate change. The water droplets, ice particles, nitrous oxide emissions and bits of soot they leave behind in contrails (condensation trails) also have a big effect. Moist, hot jet exhaust mixes with the cold air of the upper atmosphere to produce clouds of water vapour that condense into water droplets and ice particles – forming those white lines trailing behind airplanes, crisscrossing the sky, slowly expanding and drifting into the horizon. These trails, as pretty as they are, contribute to the greenhouse effect and global warming as the water, ice and soot trap the Earth's heat.

During the day, this warming effect is mitigated somewhat as the ice in the contrails also reflects some sunlight back to space. A study in the top science journal Nature found that, at a site in England, night flights – even though they only accounted for a quarter of flights – were responsible for up to 80 per cent of contrail warming.

What's more, winter flights have a greater impact than summer flights because colder winter weather is more favourable to the formation of contrails. That same study found that winter flights account for only 22 per cent of all flights, but are responsible for up to half the annual effect of contrails.

So even though it can be cheaper to fly at night, and a lot easier for your jet lag, stick to sunny skies and say goodbye to guilt.

Special to The Globe and Mail