Con-trail data would match the CO2 and temperature line. It would show another correlation that might call into question the validity of the absolute undeniable fact that CO2's correlation is causation.
There are people with simple minds that would then question CO2's role in Global Warming. We can't give those deniers anything else to hang their hat on.
It's the same reason we need to use the "Land Use" data instead of deforestation data. It would just confuse the non-believers. It's better to keep it simple and stay on message.
> We can't give those deniers anything else to hang their hat on.
Is this sarcasm? I can understand this kind of nonsense on r/politics but we should be speaking plainly and of facts at HN. I hope HN isn't turning into another propaganda machine hivemind.
I recall reading an article, but can't seem to find it, that studied changes in the atmosphere after the post-9/11 grounding of US flights. Granted, it was only free of condensation trails for a short period, but it was an unprecedented opportunity to test hypotheses related to their effect on the atmosphere.
The three or so days without US air traffic showed warmer days (because of lowered albedo, and thus less reflected sunlight) and cooler nights (because less of the earth's radiative heat energy was trapped). The thought, because of the efficiency differences of the albedo-vs-"heat blanket" effect that clouds bring, was that it was a net-warming effect that contrails cause. Scientists continued studied that, IIRC, and found that its contribution is indeed measurable, but accounts for an increase of something like 0.02° Fahrenheit.
The primary concern with commercial air traffic is their conversion of matter millions of years in the making to energy and waste products that have a more measurable effect on climate. The physical contribution of their condensation trails, via their reflective and absorptive properties, is a minor player. A player, certainly. I suspect air traffic won't decrease until we see other modes of transportation compete economically, which isn't happening any time soon.
The effect on daily temperature range is huge (1.1 to 1.8 degree C depending how you look at it). The effect on global average temperature is harder to get at, but it looks quite likely that planes increase average temperature. How much is very much in question and I'm skeptical of 0.02 degree F - that seems really low. Unfortunately we can't repeat the experiment and good models don't exist yet.
>> There are people with simple minds that would then question CO2's role in Global Warming. We can't give those deniers anything else to hang their hat on.
Why not? What if con-trails turned out to be THE major contributor after all? The implications would be that we should develop clean coal powered aircraft because they'd only emit CO2 instead of water vapor. It would kind of derail the entire "fossil fuels are bad" concept which looks like the real agenda to me.
I don't like the geopolitics of fossil fuels either, but I'd prefer if we don't create a fake crisis to change it.
There are people with simple minds that would then question CO2's role in Global Warming. We can't give those deniers anything else to hang their hat on.
It's the same reason we need to use the "Land Use" data instead of deforestation data. It would just confuse the non-believers. It's better to keep it simple and stay on message.