This is more like the sort of info I was after - rather than weddings in Mallorca
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The expedition calculated C02 from travel as 31 tonnes. There is a letter from a company called Go Balance which states that they have "retired 35 Natural Capital to fully offset the calculated carbon footprint of the" [expedition]. This appears to relate to a tree saving project in the Amazon. What do folk think of it.
I thought it worth trying to check some of the figures given on pages 87 & 88 of that report, but it’s not easy to find anything the sensible person would trust as being impartial.
The OP was about flying.
For flying the Department of Transport gives a figure of 134kg of CO2/passenger-hour.
The journey Munich – Stockholm – Keflavic for 3 people is stated in the report as generating 2.111tonnes of CO2.
According to Google the 2 flights involved have average times totalling 5h 35m, and using the D of T figure gives 2.2tonnes, which is as close as anybody could want.
But there are other figures available, including 150, 250 and 350kg/passenger-hour from the National Energy Foundation, an outfit called Carbon Independent and Quaker Green Action respectively.
The differences appear to be due to how much account is taken of something called the Radiative Forcing Factor, which attempts to come up with a factor by which the CO2 emissions of high-flying aircraft should be multiplied to take account of the other ways in which they affect climate (methane from their NOx emissions, water vapour, particulates, ozone).
It is difficult to come up with an accurate RFF and over the years numbers like 1.9 and 2.7 have been offered, so it’s not a trivial thing, and so far as I can see nobody denies that it exists.
The D of T figure does not take it into account at all, and technically that is right – it doesn’t increase the amount of CO2, but it certainly has an effect on the contribution to global warming by aircraft, and if you are going to make up for that by planting or saving trees – assuming that is possible – you really ought to plant or save 2 or 3 times as many trees as the CO2 figure suggests.