contrail

Research came out of 911 that showed the temperatures dropped 1 to 3 degrees C over the USA when all the aircraft were grounded. That appears to be traced to contrails, that cover a percentage of the sky, normally producing a warming effect.

Has any research been done on increase or decrease in surface temperatures relating to aircraft frequency of flights? Seems that one case to check would be 2008 to 2010 when there were fewer flights due to the economic turmoil...

John

Tut tut tut.

What are you doing reading the commie[1] press? Don't try the "inverse Playboy excuse" that you were only looking at the pictures :)

So, global warming has been caused by jet travel?

Sounds like bullshit to me. ...Jim Thompson

I thought it was impressive. Roughly 150,000 lbf of thrust at 600 MPH can move a lot of air.

Clicked on a link to a video. Sounds like you didn't find it to be interesting.

Pretty silly and lame stuff. OOh, some middle-aged celebrity flashed a bit of sideboob!

Condensing atmosphere and the low pressure zone above the wings turns humidity into water droplets aka clouds. You often see it off the wing tips at low levels and especially with military display aircraft.

Or for a more extreme example when going supersonic.

You sometimes see the same condensing effect off wind turbines eg.

Global cooling, not warming. There was a Nova about it.

Same as when a big volcano goes off, dust and such causes a cooling.. less sunlight reaching the earth.

George h.

From George's link above - the summery:

These results suggest that contrails can suppress both daytime highs (by reflecting sunlight back to space) and nighttime lows (by trapping radiated heat). That is, they can be both cooling and warming clouds. But what is the net effect? Do they cool more than they warm, or vice versa? "Well, the assumption is a net warming," Travis says, "but there is a lot of argument still going on about how much of a warming effect they produce."

It would be interesting to see if there was an increase or decrease in Arctic temperatures during the three day hiatus in air travel over the pole. There were still flights to/from Canada, but we are a tiny percentage of polar flights compared to the US.

More study is needed, but the premise is interesting - not to mention that one of the results of temperature monitoring has been a slight increase in night temperatures.

Certainly the IPCC was looking at the effect:

However that report is stale being from 1999. Anything post 911? I can't find anything easily...

John

Are you some kind of retard? The temperatures shot up nearly 2o in 24 hours, they did not drop. It is understood that contrails contribute to global shading ( along with particulate air pollution), not global warming.

Typical climate science. Not only do we not know the magnitudes of causalities, we don't even know the signs.

The Nova I watched said it was a cooling effect. Just like a big volcano. (I hope we can all agree that mount Pinatubo made it cooler.)

There was also some data from Australian evaporation tanks, showing that less sunlight was getting to the Earth... The presumption was that it was due to particles in the air.. from burning coal most likely. There was some speculation that we could cool our planet (if that becomes necessary) by putting more stuff in the air. We may want dirty coal and more wood burning!

George H.

Tell 'em that in London.

Is that the Nova with the bit about the 'Pan evaporation rate' ?

Cheers

I'm thinking that must be a fuel dump. Generally, contrails form way behind the aircraft, as the exhaust cools, and the ice crystals take a while to form.

Jon

It's the weight of the plane that moves the air. Thrust and velocity is what keeps it in the air.

t-surface-temperatures

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No. Aircraft do burn a lot of fossil carbon and dump the CO2 produced in th e atmosphere which has a much larger long term effect than con-trails - Geo rge Monbiot's "Heat" figured that mass tourism ought to be put on hold unti l we've got some hydrogen (or ammonia) fuelled aircraft - but air travel is merely one contributor to anthropogenic global warming, if one of the hard er ones to dial back.

Actually we do know the magnitude of the effects - in both directions - but not accurately enough to be entirely confident about the net effect of contrails.

The fossil carbon that get burnt to get the aircraft into the air and keep them there has much better documented effect (and it's all warming) but John Larkin is too pig-ignorant to realise this and much too idle to bother finding out.

The jet engine is producing the same amount of the invisible H2O gas (water vapor) regardless if it nearly immediately form contrails (ice crystals or water droplets) or spread as H2O gas into the atmosphere.

Ice crystals reflects sun light, thus reducing the daytime surface temperatures.

The water vapor is a much more effective greenhouse gas than CO2 thus reducing heat radiation out from the earth, especially during the night, increasing night time temperatures.

Thus the net effect depends if the planes fly at altitudes producing contrails or not. For west-east flights, pilots prefer the jet stream, in opposite direction other altitudes aren preferred, in addition to the FL (Flight Level) standards to avoid collisions. Thus, it is hard to predict what the net warming effect is.

How about after 9-11-2001, there was very little jet flight right after that. I took the family to Disney World soon after, there were no lines at each ride! (no one flying) The place was very slow.

Mikek