Contrails!

[Summer of 95]

I've mentioned in the past my dislike for this form of air pollution that nobody high up (pun intended) seems to be trying to tackle- well the sky over Shrewsbury this morning is so polluted that if it were at ground level it would be time for masks and handkerchiefs. I've noticed a definite increase in them over the last 5 years or so- both in their number and persistence (the typical 1980s or 90s contrail was just a thin streak behind a plane that seemed to vanish in a few minutes) but the sight today is just ridiculous and should spur people into a) noticing it and realising that something has to be done. In every direction there are wide bands of milky haze darting across the sky, some have merged together to form what could be taken natural Cc or Cs cloud by those who don't look closely enough; the sun is visibly dimmed (at times to the point where it struggles to cast shadows!), no part of the sky is free of them (the normal scenario here is to see some on the SE horizon diving towards Birmingham, and another lot low in the N caused by planes around Liverpool and Manchester; rarely do you see lots overhead) and what should be a glorious crisp autumn day of that type so rarely seen nowadays has been turned into a frustrating day of haze with the occasional glimpse of direct sunlight.

This is not pretty, it's industrial pollution just like those London smogs which is clearly affecting our weather by filling the sky with artificial clouds that reduce sunlight (reading the Vitamin D thread this could have consequences for our and other species' health) and also affect temperatures by reducing the daily temperature range (that I know has been proven).

The sky here this morning alone should kick-start those who think it's not a problem worth tackling into action- I pay my taxes and I want my sunshine back!

[VillagePlank]

Contrails are water vapour, aren't they?

[Louby]

What do you expect them to do ?

[Summer of 95]

Contrails are water vapour, aren't they?

And various components of aircraft fuel/exhaust (which provide the condensation nuclei amiong other things). Even water vapour though can be a pollutant if it creates artificial clouds that disrupt the natural weather cycle as these things do.

[Andy Bown]

I was taken aback by the number of contrails visible this morning, at one point I counted 6 planes moving roughly ESE!

We have more of a problem round here with a local company whose chimney blurts out 'steam' that occasionally convects into shallow cumulus (today is one of those days!).

[Cat 5]

Air travel is a necessity in the modern day.

I read somewhere that British Airways donated approx 6 million pound last year to help the environment. Year on year, they impliment new inititives to tackle their carbon footprint.

I would suggest that there is 10 times as much air travel now compared to 20 years ago, yet only twice as many pollutants being pumped into the atmos.

[Summer of 95]

Air travel is a necessity in the modern day.

I read somewhere that British Airways donated approx 6 million pound last year to help the environment. Year on year, they impliment new inititives to tackle their carbon footprint.

I would suggest that there is 10 times as much air travel now compared to 20 years ago, yet only twice as many pollutants being pumped into the atmos.

While I don't deny that air travel has become a necessity in this day and age, and that it has bought countless positive advances in the way we live (a few hours to get to places that used to take weeks to reach), the contrail menace is something that needs to be tackled IMO because with the projected increase in air travel it will only get far worse in years to come if people keep denying that 1) they are a form of pollution and 2) they affect the climate.

As they only form in certain atmospheric conditions surely it shouldn't be too difficult in this day and age to pinpoint the areas of sky which are (at any one time) experiencing "contrail-friendly" conditions, and divert planes away from them? I've seen an article claiming that most of the time the area of sky conducive to contrails is only 1,500 feet thick- yet we persist in sending planes right through the middle of it?

[Bobby]

I wouldn't say air travel is a "necessity". The vast majority of international flights are people going on holiday. Nice perhaps to get away to a warmer climate for a few weeks, but not essential surely.

[Essan]

Researchers are investigating how air travel can be adapted to ease its impact on the environment.

The investigation focuses on how aircraft can avoid creating vapour trails, also known as contrails. These spindly threads of condensation may not seem important but some persist for hours and behave in the same way as high altitude cirrus clouds, trapping warmth in the atmosphere and exacerbating global warming.

~ ~ ~

As the climate changes, so will the general condition of the atmosphere and the new work aims to understand how this will affect contrail formation. They have already found that aircraft could generally minimise contrail formation by flying lower in the atmosphere. Their work suggests that in the summer, when the air is warmer, restricting jets to an altitude of 31,000 feet could be beneficial. In winter, when the air cools, and contrail formation becomes more likely, the ceiling should be no more then 24,000 feet.

http://www.imperial.ac.uk/P5997.htm

[Cat 5]

I wouldn't say air travel is a "necessity". The vast majority of international flights are people going on holiday. Nice perhaps to get away to a warmer climate for a few weeks, but not essential surely.

I'm talking more cargo and business. The economy would crumble if there was no air travel.

[Stratos Ferric]

While I don't deny that air travel has become a necessity in this day and age, and that it has bought countless positive advances in the way we live (a few hours to get to places that used to take weeks to reach), the contrail menace is something that needs to be tackled IMO because with the projected increase in air travel it will only get far worse in years to come if people keep denying that 1) they are a form of pollution and 2) they affect the climate.

As they only form in certain atmospheric conditions surely it shouldn't be too difficult in this day and age to pinpoint the areas of sky which are (at any one time) experiencing "contrail-friendly" conditions, and divert planes away from them? I've seen an article claiming that most of the time the area of sky conducive to contrails is only 1,500 feet thick- yet we persist in sending planes right through the middle of it?

S95,

First up, I'm not convinced that the situation today is much worse than it was a decade ago, and in the right conditions, often with a warm front moving in, contrails can persist for a long time: this has always been true.

As to diverting planes; great theory, but it rather overlooks the fact that air corridors are designated largely for reasons of safety; shifting planes around to avoid cloud formation would end up with planes concentrated into too little space, and dramatically increased risks of air accidents.

In any case, what evidence there is suggests that contrails are helping to put a lid on current warming.

I'm talking more cargo and business. The economy would crumble if there was no air travel.

I'm not sure it would crumble: a lot of freight still goes by land and sea, but commerce would be dented.

[WhiteFox]

As to diverting planes; great theory, but it rather overlooks the fact that air corridors are designated largely for reasons of safety; shifting planes around to avoid cloud formation would end up with planes concentrated into too little space, and dramatically increased risks of air accidents.

Plus of course, flights are often routed to take best advantage of winds at higher levels. Diverting to avoid contrail ripe zones may reduce occurrence, but at the same time may burn more fuel therefore increasing emission of pollutants... The answer lies in more efficient engines. Also, planes such as the A380 may help to improve via economies of scale. Incidentally, Heathrow is forecast to be the number 2 airport in the world for large plane movement (777, A340, 747, A380) behind Hong Kong by 2025...

[johnholmes]

the post by SF sums up the procedures well.

[pottyprof]

Personally, I think they are a means of deploying weather controlling agents....

[FenlandWeatherWatcher]

Personally, I think they are a means of deploying weather controlling agents....

Hi,

Last Thurs am I counted at least 24 trails over our area of North Cambs. They spread out and cover nearly the whole sky in a grid pattern, they take about 4 to 6 hours to disperse. A beautiful sunny day was ruined.

I woud suggest anyone interested could Google "Chemtrails" for some alternate explanations. One thing I am convinced of is that if this was water vapour then why would they take so long to disperse?

Chris.

[Essan]

I woud suggest anyone interested could Google "Chemtrails" for some alternate explanations. One thing I am convinced of is that if this was water vapour then why would they take so long to disperse?

Hate to tell you this, but the Tooth fairy, Father Christmas and Chemtrails are not real

Read, learn, understand:-

http://www.grida.no/climate/ipcc/aviation/032.htm

Persistent contrails produced by aircraft have been studied for decades, for example:

http://ams.allenpress.com/archive/1520-046...69-27-6-937.pdf

They are more prevalent today for the simple reason that you you 'orrible lot insist on flying more and more and more. Although some more enlightened folk are looking at ways of reducing them:

http://www.imperial.ac.uk/P5997.htm

[pottyprof]

And here was me thinking that they loaded them with pixie dust...

[FenlandWeatherWatcher]

Hate to tell you this, but the Tooth fairy, Father Christmas and Chemtrails are not real

Read, learn, understand:-

http://www.grida.no/climate/ipcc/aviation/032.htm

Persistent contrails produced by aircraft have been studied for decades, for example:

http://ams.allenpress.com/archive/1520-046...69-27-6-937.pdf

They are more prevalent today for the simple reason that you you 'orrible lot insist on flying more and more and more. Although some more enlightened folk are looking at ways of reducing them:

http://www.imperial.ac.uk/P5997.htm

Hi Andy,

Thank you for the very informative websites which I have read through after your instruction to read, learn and understand. I didn't find an answer why the flightspaths are nearly perfect grids. If these trails are left from scheduled flights I would have thought that they would follow a pattern of the same day/week etc. when weather conditions are more or less the same. However, I have an open mind on the matter and have seen and read some convincing reports both ways.

Father Christmas is real thank you very much! I bet his reindeer don't leave trails.

Chris

[Gray-Wolf]

Father Christmas is real thank you very much! I bet his reindeer don't leave trails.

Chris

But if my lawn is anything to go by they leave something else.........

[Essan]

I didn't find an answer why the flightspaths are nearly perfect grids.

Grid pattern is simply down to flightpaths - a an airliner going from Gatwick to Edinburgh will fly south-north and be intersected by one going from Amsterdam to Dublin flying east-west, for example. Given thousands of flights over the UK every day in all directions, it's little wonder a grid pattern sometimes appears.

[skidders]

I'm sure I read somewhere recently that there are more emmisions from shipping than there are from air travel. I guess that the emmisons from air travel spread around more than the emmisions from shipping due to the height at which they are emmited and are more obvious due to the contrails. Anyway unless we stop travelling altogether, moving all the cargo back to shipping won't alleviate it!! Combatting it the way the airlines are doing so now with 'cleaner' engines is clearly the right way forward in my opinion.

[johnholmes]

if you access the CAA website they give a link to where you can purchase a map showing all the air routes over the UK. Possibly one of you may be able to point to a web site which shows one of these. Once you have seen the airways then you will appreciate why they may seem like cross roads in places when conditions are right for contrails. I'll do a quick explanation of why/when they are formed when I get time. Nothing sinister in it whatever. We, well most of us fly far more than we ever used to, hence more contrails as there are more jet aircraft about.

[pottyprof]

They don't call them contrails for nothing though John...

I mean... Take the air space over us. All those mind control drugs from wall to wall trails.. :lol:

[Chris Knight]

Hi Andy,

Thank you for the very informative websites which I have read through after your instruction to read, learn and understand. I didn't find an answer why the flightspaths are nearly perfect grids. If these trails are left from scheduled flights I would have thought that they would follow a pattern of the same day/week etc. when weather conditions are more or less the same. However, I have an open mind on the matter and have seen and read some convincing reports both ways.

Father Christmas is real thank you very much! I bet his reindeer don't leave trails.

Chris

If you see checkerboard grids of contrails, it is due to the high level winds shifting the contrails of earlier planes, thus the contrails appear to be parallel to one another. Having lived in Isleworth, about 300 feet below the Heathrow south approach path, I have witnessed distrails - dissipation trails as the planes punch through the cloudbase - the holes and tracks through the clouds roll northwards and every 90 seconds or so another parallel track is produced.

[johnholmes]

unlikely with contrails, the checkerboard as you call it is explained above, airways crossing.