Contrail Question for Skeptics - What's the Effect of Contrails on Climate?

Lone Bison

New Member
Skeptic or believer, we can all agree these lingering contrails are world wide and very widespread. Data has also shown the possibility for them to change weather patterns, effect cloud formation, and trap heat. My question for the skeptics is this;

To what extent do you think the rise in persistent contrails are effecting the climate? Do you think their effects are just localized or on a global scale?

Thank You.
 
They must be global and local since they are formed on both scales. You ask if they affect climate, and using the strict definition of climate, no they don't.
They do affect the weather by increasing cloudiness.

The net effect is debated, since the cirrus clouds they most closely resemble can both reflect insolation for a cooling and also prevent nighttime cooling for a warming effect.

I disagree that they are widespread on a worldwide basis. They will only form where airplanes fly, and that coverage is not so widespread as you may think, and many of these flights will not make any contrails at all.

To learn more about the spatial and temporal extent of flight coverage worldwide, study Mick's great interactive flight visualization app:

http://contrailscience.com/interactive-flight-map-visualization/
 
They must be global and local since they are formed on both scales. You ask if they affect climate, and using the strict definition of climate, no they don't.
They do affect the weather by increasing cloudiness.

The net effect is debated, since the cirrus clouds they most closely resemble can both reflect insolation for a cooling and also prevent nighttime cooling for a warming effect.

I disagree that they are widespread on a worldwide basis. They will only form where airplanes fly, and that coverage is not so widespread as you may think, and many of these flights will not make any contrails at all.

To learn more about the spatial and temporal extent of flight coverage worldwide, study Mick's great interactive flight visualization app:

http://contrailscience.com/interactive-flight-map-visualization/
Do you have any concerns what so ever about the rise in persistent contrails? What kind of negative consequences could we expect from contrails or are they harmless in all forms?
 
Contrails are not a personal concern to me. I consider that the negative consequences, if any, seem very small and I see no permanent harm being done. They are, after all, made up almost totally from water which was already in the atmosphere which goes back there when the contrail dissipates.. Very little of the visible persistent contrail ever came from the airplane exhaust.The airplane leaves the exact same exhaust even if no contrail forms.

Modern airliners are among the most energy efficient and low polluting forms of very quick transportation. That situation keeps improving. Air travel allows many fantastic things to happen which would be impossible without it.

There are some ways by which contrail formation could be minimized, and possibly some day that might become a reality. Probably the worst thing that ever happened to real activism to get there was the chemtrals hoax.

Ultimately, all involved in that concern will see the chemtrails hoax as setting that cause back by about 20 years.
 

This is copied from the thread on useful contrail images and graphics. It shows a very small net influence for contrails. Atmospheric conditions favorable for persistent contrail formation are present about 16% of the time. The persistent contrails have a mixed impact. During the other 84% of the time, the CO2 and water vapor emitted by aircraft are simply greenhouse gases without the complexity of clouds. The impact of air traffic on climate is proportional to the percentage of total world fossil fuel usage contributed by this industry. I think this number was posted somewhere on the forum but I don't have it at my fingertips.
 
Do you have any concerns what so ever about the rise in persistent contrails? What kind of negative consequences could we expect from contrails or are they harmless in all forms?

They are harmless to fly inside... that I can attest. As far as climate goes, more research is probably needed.

 
Thanks for the graph and great links, I will look into them.

Due to my personal experiences of witnessing contrails turn a beautiful crystal clear blue sky into a uniform haze from horizon to horizon, it has me believing it is a lose-lose situation even if they are just water vapor. Watching entire cities and regions of states/countries around the world become overcast from dissipating contrails has be effecting our climate and/or health on a great scale by trapping all that light, heat and pollution in my humble opinion.
 
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Due to my personal experiences of witnessing contrails turn a beautiful crystal clear blue sky into a uniform haze from horizon to horizon, it has me believing it is a lose-lose situation even if they are just water vapor.
Haze can also form without contrail influence, depending on weather conditions. Contrails may just come in later then, as a result rather than as a cause.
So you would have to separate these cases from those where contrails are in fact the main cause for the haze formation.

Anyway, if you look into "global dimming", the current research indicates a slight downward trend, meaning less clouds/haze overall. Of course, there can always be local peaks and reverse trends.
 
Thanks for the graph and great links, I will look into them.

Due to my personal experiences of witnessing contrails turn a beautiful crystal clear blue sky into a uniform haze from horizon to horizon, it has me believing it is a lose-lose situation even if they are just water vapor. Watching entire cities and regions of states/countries around the world become overcast from dissipating contrails has be effecting our climate and/or health on a great scale by trapping all that light, heat and pollution in my humble opinion.


One thing to remember is that the areas affected by large scale contrail formation actually represent a very small percentage of the Earths surface.
 
One thing to remember is that the areas affected by large scale contrail formation actually represent a very small percentage of the Earths surface.
In my opinion, the negative impacts of contrail induced cirrus clouds, etc are primarily psychological and local . . . the sky has been the early warming system for terrestrial species forever. . . the sky tells us when to run for cover or run from a fire, stampede, volcanic eruptions, massing armies, locust swarms, dangerous storms , etc . . . so when people complain about their marked up skies there may well be a very deep instinctual fight or flight component involved. . .
 
Thanks for the graph and great links, I will look into them.

Due to my personal experiences of witnessing contrails turn a beautiful crystal clear blue sky into a uniform haze from horizon to horizon, it has me believing it is a lose-lose situation even if they are just water vapor. Watching entire cities and regions of states/countries around the world become overcast from dissipating contrails has be effecting our climate and/or health on a great scale by trapping all that light, heat and pollution in my humble opinion.

I agree with JFDee, the way you describe the change in the sky it is more likely that the change was due to ordinary weather, and it was the change in weather that allowed the contrails to persist. In other words, the change would have happened even without contrails. If the change was accompanied b even scattered rain, it is almost absolutely certain that what you witnessed was simply weather.

Also, be aware that the world is very big. To get some perspective, use google earth this way:
draw a 200 mile diameter circle around your location. Zoom out 1000 miles into outerspace. Look at where you were, because that is about the maximum extent of your view of the sky. It is a big world. I've crossed oceans a few times on ships. Yo can sail for weeks seeing absolutely nothing at all.
 
In my opinion, the negative impacts of contrail induced cirrus clouds, etc are primarily psychological and local . . . the sky has been the early warming system for terrestrial species forever. . . the sky tells us when to run for cover or run from a fire, stampede, volcanic eruptions, massing armies, locust swarms, dangerous storms , etc . . . so when people complain about their marked up skies there may well be a very deep instinctual fight or flight component involved. . .
That's a good point, very likely a factor.
 
Watching entire cities and regions of states/countries around the world become overcast from dissipating contrails has be effecting our climate and/or health on a great scale by trapping all that light, heat and pollution in my humble opinion.
Contrails don't trap light but they might reflect sunlight which falls on them back out to space. In general light cannot be trapped. It can be absorbed, reflected, refracted or scattered.

While the jet exhaust is a source of pollution which exists whether there is a contrail or not, the contrails don't trap other pollution since they are formed so high up in the atmosphere. For the same reason, altitude, they aren't any greater and probably a lesser hazard to health than the far greater and closer sources of pollution on the ground such as road transport, biomass burning and power generation.
 
LB, regarding the idea that a general global dimming is underway due to contrails/chemtrails/geoengineering, that is not true. Long term measurements demonstrate that on a global basis atmospheric transmission of sunlight is about where it settles out to absent large volcanic eruptions which are the major actors on that stage. Here are two graphics demonstrating this, one is a measurement of how much sun is reaching the ground(transmission), the other is a measurement of aerosols specifically in the stratosphere where geoengineering would take place.

mauna loa4.JPG

35 years of backscatter aerosols.JPG

These two methods validate each other, and yet other measurements by satellite are available which also agree.
 
Seems to me there is other evidence which makes the issues of global dimming rather complicated . . .

The new GRL study also builds on a 2011 study led by Solomon showing stratospheric aerosols offset about a quarter of the greenhouse effect warming on Earth during the past decade, said Neely, also a postdoctoral fellow in NCAR's Advanced Study Program.

The new study relies on long-term measurements of changes in the stratospheric aerosol layer's "optical depth," which is a measure of transparency, said Neely. Since 2000, the optical depth in the stratospheric aerosol layer has increased by about 4 to 7 percent, meaning it is slightly more opaque now than in previous years. http://www.sciencedaily.com/releases/2013/03/130301123048.htm
Content from External Source
 
That's a good point, very likely a factor.
Thanks !!! Me thinks it is one reason Chemtrail believers have a difficult time dismissing persistent contrails as harmless . . . even when they know they are most likely only jet exhaust . . .
 
Seems to me there is other evidence which makes the issues of global dimming rather complicated . . .

The new GRL study also builds on a 2011 study led by Solomon showing stratospheric aerosols offset about a quarter of the greenhouse effect warming on Earth during the past decade, said Neely, also a postdoctoral fellow in NCAR's Advanced Study Program.

The new study relies on long-term measurements of changes in the stratospheric aerosol layer's "optical depth," which is a measure of transparency, said Neely. Since 2000, the optical depth in the stratospheric aerosol layer has increased by about 4 to 7 percent, meaning it is slightly more opaque now than in previous years. http://www.sciencedaily.com/releases/2013/03/130301123048.htm
Content from External Source

It looks like Neely and that group are leaning more toward a volcanic explanation of changes in aerosol content than the were in their 2011 paper. http://www.sciencemag.org/content/333/6044/866.abstract The 2011 paper was referenced in Geoengineeringwatch as evidence of chemtrails, although it isn't really. It does create a need to look at more than the Mauna Loa data, which was one of four data sets they used.
 
[...] when people complain about their marked up skies there may well be a very deep instinctual fight or flight component involved. . .
If this behaviour is so deeply ingrained in our genetic heritage - why doesn't it affect the vast majority of the human population?

I'm not convinced.
 
If this behaviour is so deeply ingrained in our genetic heritage - why doesn't it affect the vast majority of the human population?

I'm not convinced.
I suggest most people in the high density northern latitudes are now habituated to them presently . . . that does not mean it has no psychological effect . . . especially to those most sensitive to, for example, seasonal affective disorder (SAD). I was raised on a farm in a rural area and knew every change in the sky including clouds, smoke, dust, aircraft, birds, insects, changes in sunsets . . .
 
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It looks like Neely and that group are leaning more toward a volcanic explanation of changes in aerosol content than the were in their 2011 paper. http://www.sciencemag.org/content/333/6044/866.abstract The 2011 paper was referenced in Geoengineeringwatch as evidence of chemtrails, although it isn't really. It does create a need to look at more than the Mauna Loa data, which was one of four data sets they used.
Yes, these measurements suggest science does not have a complete understanding of all the stratospheric particulate sources and their specific contributions to the earth's energy balance . . . a most dynamic process with measurable fluctuations within longterm trends . . .
 
Yes, these measurements suggest science does not have a complete understanding of all the stratospheric particulate sources and their specific contributions to the earth's energy balance . . . a most dynamic process with measurable fluctuations within longterm trends . . .
Actually George, the 35 year stratospheric aerosol graph I cited has some very convincing analysis of the sources. They back-casted some of the spikes and identified many of the sources as being volcanic. It was publshed 2012:
https://www.google.com/url?sa=t&rct...=2vjHn2feAJHv8TwU92Z2rg&bvm=bv.57752919,d.aWM
 
If this behaviour is so deeply ingrained in our genetic heritage - why doesn't it affect the vast majority of the human population?

I'm not convinced.
I think most don't decide it's a 'sign' of things amiss until they discover the fuss being made about it by some. Then they tap into their unconscious unease about it and decide maybe it's justified. If they also have a strong anti-authoritarian paranoia (we all do to some extent) then they'll more readily buy the chemtrail script. Some though just want their curiosity about the phenomenon satisfied.

Looking at the sky allows you to see things happening far away and to anticipate them affecting you, it's a form of fortune-telling we all engage in.
 
Actually George, the 35 year stratospheric aerosol graph I cited has some very convincing analysis of the sources. They back-casted some of the spikes and identified many of the sources as being volcanic. It was publshed 2012:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CC8QFjAA&url=http://www.atmos-chem-phys.net/13/5205/2013/acp-13-5205-2013.pdf&ei=3bKkUvn0A4WgqAH21YHIDw&usg=AFQjCNHWRC7npFdANu6khNTQ8tCqYqYDxw&sig2=2vjHn2feAJHv8TwU92Z2rg&bvm=bv.57752919,d.aWM
What is the explanation for the increase in volcanic sources for SO2 in the stratosphere when no major eruptions were identified previously . . . . this does not seem to fit the assumed historically experienced mechanisms? Are we to assume an increase in small to moderate volcanic activity (previously given little notice) is now the primary cause slowing down warming when this has not been suspected before?
 
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;)
I think most don't decide it's a 'sign' of things amiss until they discover the fuss being made about it by some. Then they tap into their unconscious unease about it and decide maybe it's justified. If they also have a strong anti-authoritarian paranoia (we all do to some extent) then they'll more readily buy the chemtrail script. Some though just want their curiosity about the phenomenon satisfied.

Looking at the sky allows you to see things happening far away and to anticipate them affecting you, it's a form of fortune-telling we all engage in.
I agree with your thoughts . . . fits human nature like a glove . . . LoL!! ;)
 
What is the explanation for the increase in volcanic sources for SO2 in the stratosphere when no major eruptions were identified previously . . . . this does not seem to fit the assumed historically experienced mechanisms? Are we to assume an increase in small to moderate volcanic activity (previously given little notice) is now the primary cause slowing down warming when this has not been suspected before?
Did you read the paper?
 
I pretty much only see two kind of contrails from airplanes; either none at all or persistent contrails that last almost the entire day by spreading out into overcast year round. Here is a picture from my area of some of things I'm seeing that disgust me. This was taken last month around 9:30am.
 
You tend to notice the persistent trails more, as they are about 10,000x times more likely to be seen (visual area x persistence time)
 
How about paying attention to the weather conditions that precede and follow your noticing these contrail overcasts?
See if there's a pattern.
 
Yes, these measurements suggest science does not have a complete understanding of all the stratospheric particulate sources and their specific contributions to the earth's energy balance . . . a most dynamic process with measurable fluctuations within longterm trends . . .

I would say these measurements show an improving ability to measure particulates and correlate with sources. They have progressed from just noticing major eruptions to correlating minor perturbations with minor eruptions.
 
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