In the UK we have the highest rate of aviation emissions in the world. Because government planning policies don’t yet count aviation emissions, there is no policy to reduce them, so by 2050 aviation would contribute at least a whopping 25% of total UK emissions.
However, the latest government Climate Change Committee (December 2020) says it’s time to include aviation emissions in our accounting. And that UK aviation emissions overall should not rise at all.
2.4% of global CO2 are from aircraft fuel burn, but this becomes 2.9% when upstream emissions are included (extracting and processing fuels, source: https://stay-grounded.org/fact-sheet-climate-impact/), and 6% when total climate impact is considered.
Even at 2% of global emissions, if global aviation were a country it would rank in the top 10 emitters – more than the UK or Brazil (https://ec.europa.eu/clima/policies/transport/aviation_en)
Air travel remains a very high-carbon way of getting around, as these comparisons of carbon show (from www.bbc.co.uk/news/science-environment-49349566):
Importantly, air travel typically covers much greater distances than surface transport, so the overall emissions are much higher. So the g/km figures could be multiplied by the distance travelled to give more accurate comparative figures of emissions per journey.