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Yes, that's interesting. To be clear, the hypothesis is that contrail clouds reduce differences between max and min daily temperatures by both lowering maximums and raising minimums, thereby slightly raising average daily temperature. The researchers in that paper say:
“The temperature increases related to global warming could be made worse in areas where you have a lot of contrails,” said Carleton. “When you’re increasing the temperature, then that means there is more potential for evaporation of water, which can put more water vapor into the atmosphere and increase temperatures further by increasing the greenhouse effect.”
Nevertheless, they're not saying that contrails themselves contribute to climate change, but CO2 emissions from jets certainly do.
Yes, that's interesting. To be clear, the hypothesis is that contrail clouds reduce differences between max and min daily temperatures by both lowering maximums and raising minimums, thereby slightly raising average daily temperature. The researchers in that paper say:
“The temperature increases related to global warming could be made worse in areas where you have a lot of contrails,” said Carleton. “When you’re increasing the temperature, then that means there is more potential for evaporation of water, which can put more water vapor into the atmosphere and increase temperatures further by increasing the greenhouse effect.”
Nevertheless, they're not saying that contrails themselves contribute to climate change, but CO2 emissions from jets certainly do.
All I have said is that I observed a difference in our skies during that one 'experiment'. I also have said that when I let my co-driver look through my polarized sunglasses he confirmed my observations. What effect no aircraft had on our environment I do not know. But this has always bothered me and I wish that we did more studies of this one particular event.
My suspicion is that car, truck, train emissions are closer to the ground and that rain scrubs out a lot of the carbon particles. Where our jets deposit their carbon particles far above the earth and they stay up there for some time. But I was a truck driver and now a lab technician and not a research scientist. So it is simply speculation on my part.
I don't believe jet engine produce much particulate at cruising altitude. These aren't diesels.
The problem is that my observations and your "I don't believe" doesn't make for good scientific studies. We need the experts to look at what is really happening. Of course it is difficult to find experts that have not been influenced by the money that funds them.
The problem is that my observations and your "I don't believe" doesn't make for good scientific studies. We need the experts to look at what is really happening. Of course it is difficult to find experts that have not been influenced by the money that funds them.
Actually one doesn't need to be an expert to determine that particulate emission from jet engines isn't a big deal. It's reasonably well documented, and an issue on takeoff and landing. The particulates emitted would also produce cooling, not warming.
Last edited by DCforever; 10-18-2019 at 10:22 AM..
Actually one doesn't need to be an expert to determine that particulate emission from jet engines isn't a big deal. It's reasonably well documented, and an issue on takeoff and landing. The particulates emitted would also produce cooling, not warming.
I have shown you an article that kind of backs up my observations. It is an experiment that we hope we never repeat. But there is data that was collected that points to the fact that there is a difference when planes are not flying. I don't know if it is good or bad; but it made a difference that I observed. I just hope that our experts in climatology thoroughly go over the data, without prejudice, and can make some sense out of all that.
Actually one doesn't need to be an expert to determine that particulate emission from jet engines isn't a big deal. It's reasonably well documented, and an issue on takeoff and landing. The particulates emitted would also produce cooling, not warming.
Yes and No....here is a discussion of how the cooling and warming work when it comes to contrails.
IT IS the contrails that contribute to global warming. The smoking gun is that ALL the global warming is due to an increase in nighttime temperatures. Daytime temperatures have remained flat.
It is the contrails that contribute to global night time warming.
It is way past time to limit jet travel to save the planet.
IT IS the contrails that contribute to global warming. The smoking gun is that ALL the global warming is due to an increase in nighttime temperatures. Daytime temperatures have remained flat.
It is the contrails that contribute to global night time warming.
It is way past time to limit jet travel to save the planet.
Actually not all temperature increase is at night, but that much of it is at night is just the physics of the process. To use a simple analogy, global warming works like a blanket in that it slows the cooling of the part of the planet that is experiencing night.
No more contrails at night than any other time. Probably less as most travelers prefer to travel during the day. But since 1/2 the planet is alway in day and 1/2 a night these is even less difference.
It's time to put aside silly theories that have no scientific support and focus on what is important. Reduction in GHGs overall at the lowest cost -- coal fired power plants.
I think everyone is ignoring the info in my OP: the newly published studies use computer derived data that completely ignores the shading effect of contrails on incoming solar radiation and conclude that contrails cause warming...While the single, actualobservational study available (post 9/11 episode) shows contrails cause cooling. Apparently more shading than heat trapping.
I think everyone is ignoring the info in my OP: the newly published studies use computer derived data that completely ignores the shading effect of contrails on incoming solar radiation and conclude that contrails cause warming...While the single, actualobservational study available (post 9/11 episode) shows contrails cause cooling. Apparently more shading than heat trapping.
Do you have a reference to the 9/11 study that showed contrails cause cooling??
The skies cleared dramatically for two days on 9/11. That should have resulted in COOLER night time temperatures due to the lack of contrails.
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