The flight path from San Francisco to London only goes over a small section of Eastern Canada. The return flight covers more of Canada, but only the eastern half. There are probably very few flights over Western Canada, and a minimal number over the eastern half north of Toronto and Montreal. All the large Canadian cities are within a few hundred miles of the southern border, so it seems safe to guess that most of Canada is normally contrail free.

In other words, this study is probably irrelevant.

Yesterday was the first day when it was warm enough to attempt to fly the hydrogen powered rocket I got the kids for Christmas. At about 4:00 a small, narrow bank of cirrus clouds blocked the low angle sun and it immediately became uncomfortably cold - until the sun dropped below the clouds.

The rocket was pretty cool, except that it had an electronic voice which kept spewing global warming propaganda - "Hydrogen does not cause global warming." A curious statement given that the hydrogen was generated using electricity.

Reminds me of a story (perhaps apocyphal) that I read a couple years ago about some not-so-high-level contrail researchers who snagged a grant, rented a 707 and flew it around in circles over the Pacific for several hours to see what, if any, effect this would have on cloud formation. This is known as the "poking things with sticks to see what they do" investigative method - certainly a time-honored tradition among my in-laws.

Anyway, the story goes, the concentration of contrails did indeed induce further cloud formation - to the extent that a storm formed and ended up drenching the Southern California coast. Oopsie!

Not particularly GW-related, but pretty funny, in a Darwin Award way, if true. Anybody else hear about this?

Do "we" know what kind and magnitude of "adjustments" were made to the USAian and Canadian data sets?

How do the adjustment algorithms differ?

This artical interests me greatly, this is the question for everyone to examine. In the sat photo, can anyone calculate the average length of the longest group of contrails. In this snapshot of "contrails" one has to ask what altitude these trails are, what is the composition of these trails and what plausible cloud forcing is resulting from these "contrails". My understanding of normal jet contrails is that they are composed of primarily water vapour that condenses into trails of ice crystals (Usually about 30,000 plus ft). Then after about a mile or so the normal contrail sublimates to invible gass water vapours. Thus, how do we explain contrails being so persistant for what appears to be hundreds of miles? If these were just water vapours then why are they sooooo long ? ;)

Here is the site of the co-author of contrail study -
http://facstaff.uww.edu/travisd/

see 'Recent Research' for *.pdfs of same.

Skimming his papers, their continental US temperature dataset included 4,000 stations. The Canadian work reports using 112.

Reply: Good find Jay!

I agree with Patrick. And just because the temperature increased 1.5C during a 3 day period doesn't mean anything. It's called a heat wave, they happen. It is irrelevant.

Patrick, I share your doubts on hydrogen - for many years now. Yes it burns to water, but where do you get it from and what form of energy do you use? I have seen some things on fermentation techniques, not yet commercial, but most rests on electrolysis.
Similarly on "biofuels" most rely on converting a tiny proportion of the plant to alcohol. I can't make sense of that either in economic or ecological terms. If you are converting cellulose/ starch/ sugar to alcohol using the whole plant and specific enzymes, it might make sense. But if you are just picking the corn, eat the thing - it's more valuable that way. The big attraction of trees is that you can use the whole plant, not just a bit. But you can't pour a tree into your gas tank, so there is still some work to be done.

George N: Answer to long contrails is time-laps photography. Nothing special.

Patrick: Today, you made me laugh. Thanks.

Terry,

I haven't seen any evidence that biofuels are better for the environment. Probably worse. Combine that with rapidly rising food prices and it sounds like a big mess.

There are lots of hungry people in the world. Intentionally reducing the food supply in a vain attempt to ward off the AGW bogeyman, sounds as misguided and primitive as any excesses from the darker periods of human history.

Brett

Where is the sat photo from? I have seen my pictures of our planet but never once noticed any contrail...

Reply: it is a NASA photo that I googled

I suppose one could argue both ways on this. On the one had contrails are short lives, and thier presence depends upon many things (moisture levels, turbulence, etc...). On the other hand, in areas of high air traffic density such as Atlanta and Chicago, contrails may have some effect (cooling during the day, warming at night). I've never seen any study that definitely said contrails do in fact have a change on our climate. This study would be hard to conduct, as surface temps could be affected by microsite issues (low level cloudiness, surface temperature advection, onshore/offshore wind flow, precipitation, etc...). The best play to test this out would be the Pacific Ocean. But, then again, how many contrail exist over Fiji, Pago Pago, or Kawajalien?

Not so fast Bob, unless one knows exactly what kind of time lapse we are talking about your answer is a non answer. Seccondly if this was a satelite that is in a geosynchronous orbit then yes a time lapse is possible on the order of how far and how long it takes for a jet to go that far. Furtherthermore, upon closer inspection of the "contrails" one can see that some trails have "gaps" in them, so what does that mean? Engines turning on and off? Or are other substances added into the trails? Also you can see clearly the contrails at diferent stages of expansion, where some are freshly laid out and others are "smeared" indicating a long term persistant quality as they spread out and become part of the general cloud field. So, what kind of time lapse are we talking? If this satelite pic was generated from a non-geosynchronous orbit than your suggestion is very unlikely to reediculous. Keep trying folks!

A small personal observation:
Several weeks ago, January 2008, I was hiking in the mountains on the north side of the San Fernando Valley in the Los Angeles region. At about 3000 feet altitude, I had a good view of the sky over the valley and across to portions of the shoreline of the Los Angeles area. The sky was filled with thin linear clouds formed from jet trails going to LAX, Burbank Airport and others, since there is a lot of overhead traffic.
Without the jets, it would have been a completely clear blue sky.

George, it appears you're right--or I'm easily swayed. Note, however, that the effect seems to diminish or stop near the northern borders of Alabama, Georgia, and South Carolina. So are the contrails within that hazy cloud layer or above?

Regards

Don't biofuels get about 20% less mpg, is this factored in on how much CO2 is produced or do they just go by the gallon?

Hey George N:

I suppose those "contrails" last longer when you mix in barium sulfate & aluminum oxide, among other things! :()

Note, however, that the effect seems to diminish or stop near the northern borders of Alabama, Georgia, and South Carolina.

There's a bad historical joke about slavery and the confederacy lurking in there someplace ...

To Anonymous -

Fuels can be compared by something called a Fuel Value, which is the quantity of heat produced per gram of substance. According to the Chemistry textbook that I use, the Fuel Value of Gasoline (without any Ethanol) is 48 kJ/g whereas Ethanol is about 30 kJ/g. So, yes, you do get a lot less energy from the combustion of Ethanol. The quantity of carbon dioxide also varies with the percent of carbon found in each gallon. Gasoline is about 85% carbon whereas ethanol is 52% carbon. Thus, the gasoline produces more CO2, but that is offset by the fact that you have to burn more ethanol.

The effect contrails have would be to hard to to gauge, except for clear, calm days. During those conditions,there could be some effect. I wonder what kind of voodoo goes on in the adjustments of data sets.

Much more research will have to be done. Comparing the effects of natural high cirrus and artifical creation by contrails. An extremely difficult task to say the least.

OK Folks, I have posted this site before, but it so aptly applies to this thread that I have to share:)
http://www.newruskincollege.com/gorbachevbushartificialcloudsinstitutenewruskincollegecom/id7.html

I think I hear those black helicopters again.

Jean Raines: Yes it would be so beautiful to see those blue skies, and to see a sunset without abnegating it's beauty to the infrared spectrum it
falls victim to. This board doesn't see the obvious beauty around us but bows it's head to a higher authority (their own ego, and well informed bragging).Most normals are out looking for real answers to scientific questions. Like does the Jet activity make the days warmer? Here they don,t like to talk about the concept of global warming. I don't know why?(just kidding)I do know. Poor Brett has had to deal with these fringe folks for a while. They don't talk about the topics either. Just Existential to obscurity. Welcome Jean. And good luck!

Kipp, are you not a part of this board? Or is that the AGW elitisim rearing its head.

Kipp, do you want us to do away with air transit?

Let's talk about global warming, the earth has shown an increase in temperature over X years, but now prove that is our fault, prove that if we did not increase CO2 like we do, there would be no warming, or the warming would be much much smaller. Also, please prove that the small fraction of a percentage point of "accurate data" is enough to wholeheartedly say that this is not the the way the earth is supposed to be, this is not a natural cycle.

You want to discuss AGW, then do it!

Kipp,

On a previous thread, I and a few other asked you to elaborate on CO and CO2 and their carcinogenic properties. Never heard from you. What's up with that?

You brought up that subject, not I. I would still like to hear your thoughts on these alleged carcinogenic compounds.

Buehler....Buehler.