In order to tot up these differently paced warming impacts into a single carbon footprint number for a flight or any other activity, it’s necessary to decide what time frame you’re talking about. Conventional wisdom is to add up the total warming impact of all the different greenhouse gases over the period of a century to create a nice, round but ultimately arbitrary number.


If, by contrast, we shifted the focus to a much shorter time period – which arguably would make more sense, given that the next decade or so could turn out to be make-or-break in terms of avoiding climate tipping points – then the impact of vapour trails and other short-lived impacts look massively more significant.

via The surprisingly complex truth about planes and climate change | Duncan Clark | Environment | The Guardian.