"The most comprehensive analysis so far of how much warming is caused by aeroplanes has found that flying’s contribution to global warming nearly doubled between 2000 and 2018. Rapid growth is far outpacing efforts to reduce its contribution.
“It is growing so rapidly,” says David Lee at Manchester Metropolitan University in the UK. “It’s just astonishing.” The study only goes up to 2018, before the big decrease in flying due to the coronavirus pandemic, but this is just a blip, says Lee. “It’s not going to make much difference in the long term.” (New Scientist: 3rd Sept 2020 here.)
"There is a disconnect between aviation's role in our personal and collective carbon emissions. Air travel dominates a frequent traveller’s individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO2) emissions. This is because there are large inequalities in how much people fly – many do not, or cannot afford to, fly at all [best estimates put this figure at around 80% of the world population – we will look at this in more detail in an upcoming article].
The second is how aviation emissions are attributed to countries. CO2 emissions from domestic flights are counted in a country’s emission accounts. International flights are not – instead they are counted as their own category: ‘bunker fuels’. The fact that they don’t count towards the emissions of any country means there are few incentives for countries to reduce them." (Our world in data October 2020 here.)