A valid conclusion?

[Weird Harold]

http://www.registerguard.com/news/2002/08/08/3a.nat.contrails.0808.html

By MICHAEL STROH, The Baltimore Sun

On Sept. 11, the Federal Aviation Administration grounded all commercial aircraft in the United States following the terrorist attacks. For three days, the skies were nearly as clear and quiet as they'd been since the Wright Brothers skidded aloft.

It was a difference not lost on David Travis. ``I realized this was an opportunity to study what the U.S. used to be like before the aviation age began,'' the University of Wisconsin atmospheric scientist says. Specifically, he realized he had an unprecedented chance to answer a question that has vexed him and others for decades:

Do the wispy tracings left behind by jets - known formally as contrails - somehow alter the environment?

His study, published in today's edition of the British journal Nature, offers the first direct evidence that contrails do have a slight but measurable effect, making the days a little cooler and the nights a little warmer when jets are flying.

...

Is three days without contrails enough to make such a sweeping conclusion? Especially when the comparison is against an average temprature over about ten years? (the exact dates used are in the full article.)

1 to three degrees celsius doesn't seem to me to be outside the statistical devation of the averages they used for comparison.

Three days without any air traffic at all is indeed unprecedented, but hardly enough time to draw conclusions about climate effects.

 

[Guest]

Assuming you're correct would you suggest a longer period of
empty sky?

3 months,6 months?.

 

[Weird Harold]

Assuming you're correct would you suggest a longer period of
empty sky?

3 months,6 months?.

I would suggest not wasting money on worrying about it.

As another link in the Flat Earth attempt to wind the clock back it's very weak and actually counters their argument that Jet Aircraft are causing ozone depeletion and global warming.

PS: if they want to study the affect contrails have, there are numerous ways to measure how much radiation contrails reflect in each direction without grounding aircraft.

 

[sigh]

Without seeing the statistical workup, it's impossible to say if the conclusions are valid or not.

Now, do I care if the conclusions are valid? Not really. I don't imagine we're going to do away with air travel any time soon anyway.

 

[sigh]

As another link in the Flat Earth attempt to wind the clock back....<snip>

Are you suggesting a conspiracy here? What is this?

 

[Weird Harold]

Are you suggesting a conspiracy here? What is this?

Nope, not a conspiracy. Luddites, Flat Earthers, Creationists, Tree-huggers, et al, aren't conspiring to commit fraudulent science. Say rather that they all seem to suffer from mass delusion and an inability to think logically.

I'm not sure how the statistical analysis can overcome such a small sample. I don't doubt that the long term data is reasonably accurate and statistically sound.

I just wonder if three days is enough of a sample to be valid, and if three days is enough time for the atmosphere to settle from 98 years of air travel.

 

[lienm]

Theory

You are probably right it would not be accurate to base data on three days of free skies as weather anomolies cannot be removed satisfactorily from datato give a proper normalised result.
It would be fair to say that records showed some difference from a large mass of data used to determine the norm but then to try and isolate three days and compare not realistic.
Theory may well be valid but proof is not proof because it is not conclusive

 

[Weird Harold]

Re: Theory

Theory may well be valid but proof is not proof because it is not conclusive

To be fair, I have watched contrails spread into high hazy clouds. When the conditions are right, contrails are very probably responsible for weather forecasts falling a few degrees off the mark. It also stands to reason that, when conditions are right, many contrails will have many times the effect.

Logically, the theory holds water -- I can't say the same for this study because there are too many other variables that could explain the results.

 

[SINthysist]

I agree 100%. It was an interesting, but meaningless analysis. Now the article at the source I read it from was even worse because in the very last paragraph it had to add the caveat that this effect by no means offset the global warming caused by the jet burning hydrocarbons.

Now to read the other replies...

 

[SINthysist]

As someone who worked in the field and was in the Air wing of the Marine Corps, I'd have to say that contrails are too thin to have more than a negligible, local effect. The heat sinks caused by city streets alter temperature much more dramatically, and can sent columns up into the air creating localized thunderstorms.

In contrast, contrails are the stuff dreams are made of...

 

[Dillinger]

I'd say the time frame of the study was much to short to draw any valid conclusions. Additionally the scientific method calls for valid AND repeatable results. Even if there is something to this, one study doesn't prove anything.

 

[Shy Tall Guy]

All valid observations - within this thread that is. One I didn't hear/see mentioned was that this ban was only over the US and we are talking global weather. I didn't read the article to see if this was addressed, and maybe the observations were limited to the US, but weather is a global phenomena and besides only observing what happened for three days and comparing it to ten years, what about only observing what happened in the US for three days and comparing it to the world for three days??

Clear as mud?

 

[sigh]

Unfortunately, reading an article about a scientific study is about as useful as a nail clipper when you go out to mow your lawn. There is little or nothing to be gained from such an activity. They invariably get it wrong. I do agree though that such a small sample seems inadequate, but again, I need to read the study to be sure.

SIN, I have only one (that's not so bad, is it?) point to pick with you. I often see arguments regarding the environment that say in effect, "so what?, the impact of this other thing is much worse" (I'm referring to your comment on the heat sinks caused by city streets). Just because there might be other problems in the world, doesn't justify continuing a problem that can be controlled.

Of course, this one can't be controlled either. I wonder what it cost us to do this study?

 

[Never]

Weird Harold:
"Nope, not a conspiracy. Luddites, Flat Earthers, Creationists, Tree-huggers, et al, aren't conspiring to commit fraudulent science. Say rather that they all seem to suffer from mass delusion and an inability to think logically."

As a confessed tree-hugger I'm not feeling too cozy about being grouped with the others.

And, no, three days isn't enough time.

 

[phrodeau]

The job of a scientist is to collect observations and produce theories to explain them. He did what he could with what was available.

This study provides the first direct evidence to support his theory. Eventually, more evidence will be collected and the theory strengthened or weakened by it.

 

[sigh]

Weird Harold:
"Nope, not a conspiracy. Luddites, Flat Earthers, Creationists, Tree-huggers, et al, aren't conspiring to commit fraudulent science. Say rather that they all seem to suffer from mass delusion and an inability to think logically."

As a confessed tree-hugger I'm not feeling too cozy about being grouped with the others.

That thought crossed my mind too, Never.

 

[Never]

sigh:
"That thought crossed my mind too, Never."

Perhaps he meant Eco-Terrorist?

 

[Shy Tall Guy]

Weird Harold:
"Nope, not a conspiracy. Luddites, Flat Earthers, Creationists, Tree-huggers, et al, aren't conspiring to commit fraudulent science. Say rather that they all seem to suffer from mass delusion and an inability to think logically."

As a confessed tree-hugger I'm not feeling too cozy about being grouped with the others.

As a creationist I don't feel comfortable being grouped with Tree-huggers either.

Seriously, I believe WH is referring to the tree-huggers who literally hug trees to save their spirits from the evil corporations that want to kill them with chain saws, and to the Creationists who believe that God created the universe in six days, six thousand years ago, and sprinkled fake dinosaur footprints and bones around jsut to tempt us into believing in evolution so he could separate out the good souls from the bad.

 

[ma_guy]

Nope, not a conspiracy. Luddites, Flat Earthers, Creationists, Tree-huggers, et al, aren't conspiring to commit fraudulent science. Say rather that they all seem to suffer from mass delusion and an inability to think logically.

I'm not sure how the statistical analysis can overcome such a small sample. I don't doubt that the long term data is reasonably accurate and statistically sound.

I just wonder if three days is enough of a sample to be valid, and if three days is enough time for the atmosphere to settle from 98 years of air travel.

You are exactly right. The conclusion can only be valid if ALL other possible causes are eliminated and there is NO way that can be done in a 3 day study. We've been studying the atmosphere for decades and still can't pin-point an exact cause for global warming.

There IS an entire group out there that is convinced that contrails are a huge government plot and that the government has the ability to control global weather patterns. This is the kind of stuff they feed off of.

 

[Problem Child]

I believe the scientific community is becoming more and more solidified in believing that global warming is real and that human beings are responsible for a large part of it.

Having said that, it took decades of research on global warming to come to this point, and there is still a lot of debate. Debate over whether dumping millions of tons of carbon into the air every year from all sources causes a minor global temperature change.

Compared to that, I can't see how three days worth of airline contrails can make a spit-in-the-ocean's worth of difference, and I'm sure whatever change there was is not statistically significant. Add to that (as has already been mentioned) are all the other modifying factors. It's just much to complicated a question to be answered with three days data.

 

[lovetoread]

[/]lot[/i]

Psst. Spelling Buddy?

You need to edit that and make it lot.

 

[Shy Tall Guy]

There IS an entire group out there that is convinced that contrails are a huge government plot and that the government has the ability to control global weather patterns. This is the kind of stuff they feed off of.

IF anyone doubts this, jsut go to one of the conspiracy newsgroups and see if this has been referenced yet - if not, post it and watch the fun begin.

 

[Problem Child]

I never claimed to be your helpful HTML buddy.

But, thanks for the correction.

 

[ma_guy]

IF anyone doubts this, jsut go to one of the conspiracy newsgroups and see if this has been referenced yet - if not, post it and watch the fun begin.

They can start here:
http://www.rense.com/politics6/chemdatapage.html

(This a page of nuts who think contrails are chemicals being sprayed by all the governments in the world to control the weather and populations. They've renamed them "chemtrails".

Next time you aren't feeling up to your "normal" self you'll know why.

 

[RhumbRunner13]

They do exist.......

Enough Chemtrails

From Marlene LaVonne
3-10-2

Dear Jeff - On Mar. 5th at 9 in the morning, I was visiting the power vortexes of Sedona, AZ. I looked up in the sky and with my very own eyes observed about 3 jets (they were visible to all) doing the crisscrossing pattern. Shortly after, (about 1 hour) the skies were blocked and I noticed my breathing became impaired and my eyes burned. Jeff, when are we all going to stop talking about this and DO something about it?

Kind Regards, Marlene La Vonne


C'mon people, let's do something about it!

Anybody ready for a beer?

Rhumb