Contrails

[W5]

https://www.avweb.com/aviation-news/contrail-avoidance-possible-but-uses-more-fuel/

 

Contrail Avoidance Possible But Uses More Fuel

A small study facilitated by American Airlines and Google has shown that it’s relatively easy to cut the amount of contrails created by airliners but it comes at a fuel penalty. American supplied the aircraft for 70 flights and used software developed by Breakthrough Energy to create flight plans that avoided frozen water vapor-producing conditions. In the trial they were able to reduce contrails by 54 percent but maneuvering to avoid the contrail conditions used about 2 percent more fuel. And even though more fuel was used, the contrail avoidance might be worth it from an environmental point of view, according to the authors of the study.

 

“Avoiding contrails might be one of the best ways to limit aviation’s climate impact, and now we have a clear demonstration that it’s possible to do so,” said Marc Shapiro, Breakthrough Energy’s director of contrail studies. Contrails were generally considered to be a harmless byproduct of jet fuel combustion but their impact on climate change might have been underestimated. The artificial clouds trap heat in the atmosphere.

According to the Dallas Morning News, Google and Breakthrough used artificial intelligence to modify the flight plans for the 70 flights to steer clear, as much as possible, from the altitudes, weather and humidity where contrails were most likely to form. Then Google used its satellite cameras to check the results. Jill Blickenstein, American’s VP of Sustainability, said pilots played a big role in carrying out the research. “One of the main reasons that we had success is that we had a small group of pilots who were really excited about trying this,” she said, adding that others who were recruited also quickly got interested in the project.

 

 

[Seeker]

1 hour ago, W5 said:

 The artificial clouds trap heat in the atmosphere.

 

I thought the contrails reflect sunlight and reduce the amount of heating in the atmosphere.  Didn't Bill Gates have some plan to seed the atmosphere with particle to reflect sunlight?

Yes, he did:  https://www.popularmechanics.com/science/a35938287/bill-gates-solar-geoengineering-block-sunlight-research/

[Vsplat]

Clouds work both ways.

Daytime, some wavelengths reflect back to space, others pass through, still others are absorbed by the cloud and raise cloud temperatures.

At night the cloud layer releases that stored heat both up and down, but also reflects and absorbs heat from the surface that would otherwise radiate into space.  This limits the amount of overnight cooling, so the next morning heating cycle starts from a higher set point that it might have on a clear night.

Vs

[Seeker]

So which is the greater effect or is it a wash?  Do contrails help cool the earth by reflecting some sunlight away or warm the earth by preventing some heat from leaving?  The cynic in me thinks it's a big nothing-burger and that it's an idea created by the climate crazies for fame and funding. 

It's interesting and thanks for posting it but, IMHO ,of all the things on this planet worth fixing contrails are so far down the list as to be insignificant.

 

[Vsplat]

It's not universally one way or another.    It would depend on seasonal things like OAT and hours of daylight, but also on concentration.  On the NAT with the close spacing of high altitude tracks in use now it might add up.

[Seeker]

On a somewhat related topic I just got my Climate Action Incentive Payment today.  Maybe I could donate it to the Contrail Avoidance project.