Study: Jet Exhaust Affects Weather 191
An anonymous submitter writes: "Warp 10 speeds may affect... Ooops, wrong story.. Apparently, jets are affecting the weather and contributing to about a 3 degree daily temperature variation. Even a single degree variation in overall temperature (climate) is significant, but I'm not certain how significant is 3 degrees in local temperatures." We mentioned this before - there was a Wired story - but now their work has been published in Nature and the AP has picked up the story.
Bah (Score:4, Interesting)
As usual, no one reads the article (Score:3, Informative)
Re:As usual, no one reads the article (Score:2)
Refer back to "no one reads the article."
They determined this from the break in flights after 9/11. Note that although plane flights stopped, the airports themselves did not get torn down or anything like that, so this change is independent of the existance of airports.
The airports may have a _similar_ effect, but it is different from the one caused by the planes themselves.
Re:Smoking/Pools (Score:1)
Not to mention that air inside most restaurants and other commercial buildings is exhausted and replaced with outside air several times a day (probably a few times every hour). Can the same thing be said about the pool? This is an HVAC issue.
Water usage (Score:1, Interesting)
I read once (can't find it now) about how many more gallons of water are used depending on temperature. It was amazing how the amount used went up per degree increase.
don't encourage them (Score:3, Troll)
This will only encourage the weird science crowd who are looking at the contrails as "chemtrails" and look at the whole thing as an effort to control global warming, or do other mean and nasty things.
Google reveals about 18,000 hits on the word "chemtrails" [google.com] alone. Have a party.
Re:don't encourage them (Score:2)
This is fair and square experimental science. It doesn't break theoretical ground, but measures the magnitude of a predictable effect. And as a trained gubmint meteorologist, I find the reported magnitude of the effect both surprising and interesting.
I couldn't care less what the chemtrail wackos will make of this, and we can't start modulating the spread of valid scientific information with concerns about the effect it will have on people with bad memes on their brain.
If I had mod points, the parent post would earn -1, troll.
Existence of nuts shouldn't prevent science (Score:4, Insightful)
Lunatics believe that aliens visit earth on a regular basis to indulge their twisted ass fetish. When we look for evidence of martian microbes, are we just encouraging them (lunatics, not martians)?
This contrail weather effect is good science - the deviation they've identified in temperatures is statistically significant. Now, that isn't proof; statistically significant variations do arise by chance, and you can certainly get a stistically significant result that confuses the real causality (Less people Drove around Sep 11th, did that cause a significant local drop in CO2? Is this an incidental effect of overall climate change? So on and so forth.) However, just because it isn't proven, we can't dismiss it either (personally, I think contrails probably do effect the weather,) just because there are loonies who believe something similar.
Re:Existence of nuts shouldn't prevent science (Score:1)
Cell phones don't cause brain cancer. This is Limbaugh-esque arrogance.
Studies are incomplete, &c. &c. &c. Avoid sounding so self-assured with presenting any data. There are no 10 yr usage studies much less 25 or 40 yr studies.
Re:Existence of nuts shouldn't prevent science (Score:2)
Uh, you did read the article yesterday about Conspiracies and Probabilities right? You know the part about clusters happening naturally but people wanting to attribute causal affects to them?
Re:Existence of nuts shouldn't prevent science (Score:2)
If you want to talk about damning paperwork, go ahead and talk about that. You should also mention the study at the University of Washington that found there was a possible risk of cancer from cellphones and then had their funding cut off as soon as they published their results. Guess which industry had been funding the research?
However when you throw in "I know two people who got cancer and they both use cell phones! What are the odds of that?" it doesn't really help your argument. In fact, because of that whole trying to put together patterns bit in the above mentioned article, people who know how meaningless that statement is tend to assume that you don't know what you're talking about and let that view flow over even into the reasonable evidence that you have presented.
If you ever find something that seems to be 100% sure proof of the existance of aliens, don't also announce at the same time that you've been abducted and probed by alien visitors to earth, even if you're sure it's true.
Four days? (Score:3, Insightful)
Re:Four days? (Score:1)
But I've not read this article, so I could be talking out my ass.
Re:Four days? (Score:3, Informative)
Your right, (Score:3, Funny)
Oh bother.
Don't be so short-sighted... (Score:4, Insightful)
(Fact: Venice is sinking and many of its famous piazzas are frequently flooded. Fact: Bangladesh is under constant threat from flooding, which affects millions and kills thousands practically every year in recent history.)
I find it curious that a great number of people who comment on
If there was a small chance that toxic chemicals were seeping into your drinking water then you'd be mad to dismiss it so nonchalantly. If there was a small chance that your car's tyres were defective and could kill you then you'd be mad to ignore that too.
Similarly, if there's a small risk that your actions (together with that of the rest of the civilisation that you live in) was causing major damage to the ecosystem then you'd have to be a complete idiot to ignore the possibility.
Somehow, on
Re:Don't be so short-sighted... (Score:3, Insightful)
Venice is a total red herring. The reason Venice is sinking is primarily caused by the depletion (mostly by the mainland) of the aquifer that extends out under the bay and the island. I don't recall whether water usage has changed since identifying the problem, but I do remember that a large portion of the depletion actually resulted from WW2 era industrialization.
Bangledesh flooding might in fact be related to global warming, but the direct cause is increased rainfall (e.g. more/stronger monsoons) in the local river basins.
In neither case is changing global sea levels the main source of their problems. I suspect that there might be some islands that have a bone to pick with sea level change, but at current I don't know of any locales where this is their primary environmental concern.
As for chemicals in drinking water or defective tires, of course there is always a small chance that these things are happening to me. What you probably meant to say was that it would be foolish to ignore it if there was some evidence to suggest it was true. While I've never seen anything particularly bad about my tap water, there certainly is at least some evidence to suggest global warming is happening and is potentially very bad.
Honestly though, I don't think it's "mad" for most people to ignore global warming, because in all reality most people are irrelevant to the debate. Few people have the scientific background to contribute meaningfully to the debate, and even fewer are in the position to make policy decisions that will matter. Sure, it's all well and good that you recycle and turn out the lights in empty rooms, but even if the whole world started doing that it's unlikely to matter as much to global warming as, for instance, if US politicians insisted on a 10% increase in car fuel efficiency.
Maybe you think advocacy matters in setting policy? But even if you and a million of your friends yelled about the dangers of global warming till blue in the face, politicians are only going to do enough to placate you or shut you up, unless you can present a well reasoned, solid, and scientific case to justify the huge expense of actually doing anything significant about global warming. Frankly, I wouldn't want my politicians to spend billions of dollars because the sky MIGHT be falling; I'd want them to be pretty damn sure. Which goes right back to why most people are irrelevant.
Ultimately, what to do about global warming will be addressed in research labs and government offices, and what the average Joe thinks won't matter very much. I suppose the nebulous fear that people feel about global warming does help keep research dollars flowing, but other than that it's pointless anxiety for most people.
Re:Don't be so short-sighted... (Score:2)
And it's _still_ possible that we're at risk for an ice age. It's even possible thatthe factors to start the next ice age have already occured and we haven't seen the results because of human induced global warming.
And even if that were the case that wouldn't necessarily mean global warming is all good. We might be overdoing the global warming bit so much that we get flooded anyway instead of getting covered with ice. The cities that end up under water won't care too much whether it ends up being of the liquid or solid variety.
If you mix the right proportions of chemicals you get gunpowder, screw up the proportions even a little and it can explode during the manufacturing process and kill you. Oxygen and sugar both damage living tissue over time, so if you don't breath and don't eat you'll live forever, right?
As much as the average person wants it to be, most things in the universe are not a simple yes or no proposition. If we decide not to bother with anything that doesn't have a simple answer than we might as well just go back to to hitting each other over the head with sticks and stones.
And if we always wait until the trends are so obvious that they can't be ignored, most of the time it will be too late to do anything about them.
Re:Don't be so short-sighted... (Score:2)
Really, look at your own arguments, yous ay we know nothing about the climate 30,000 years ago. If that's the case, how do we know there was an Ice Age then? If geological data isn't giving us very good data, then how do we know that Antartica was near the equator a few hundred million years ago?
They've got estimates of temperatures from ice core samples going back to the last ice age. The fossils and geologic samples from Antartica might not tell scientists much about conditions at the pole that long ago but it tells them a _lot_ about what conditions were like near the equator. If they want to to know about polar conditions they look at geologic data from other continents.
trail of this story (Score:1)
Short fictional address by President McCain (Score:1, Interesting)
Commondreams.org has written a fictional address [commondreams.org]; conservatives and non-believers will call it propaganda, but then, as the weather patterns continue to change and the news [gbrmpa.gov.au] stories about environmental catastrophes keep coming, they may have some trouble making the charge stick...
Small Statistical Sample (Score:3, Insightful)
According to most theories the earth is 3.5 billion years old. We (humans) have been measuring the temperature for less than 200 years. 200/3.5X10^12=5.7X19^-8. We are attempting to calculat trends in global warming with
Re:Small Statistical Sample (Score:1)
Re:Small Statistical Sample (Score:2, Informative)
Ever heard of Population sample ? (Score:2, Insightful)
The amount of measure don't say anything about a model being wrong or correct. The problem is first to determine if the measure we did amount to correctly represent the whole "populaztion" we are measuring or not, second whether those are following the known modell or not.
Measure on 4 days are enough to establish a modell of temperature on variation of monthes or year. WE DO NOT care on temperature variation on geological scale for that study ("does jet have influence on local temperature or not")
Same pr9oblem with your reasonement on global warning. it doesn't matetr if we have a popualtion measurement on 0.000001% of the history of earth. We are effectively measuring something on the historicalö size (last 200 years) and that is what matters for our modell and sampling. We are trying to see if we influence temperature enough so that it becoems dangerous for US ("now"). Not that wetheter such warming occurs at slow geological scale. Who cares if temperature change by 10 grad celsius in 10 power 7 years, we are seing if we are generating the same change in 100 years...
Everything is a matter of sampling and scales. The aforementionned Competent statistician would mention it to you. Take a representative number of the population and you will have a good enough snapshot of the population (within error).
Now i am waiting for somebody with the infamous proverb "there are 3 types of lie : Big lie, DAmned lie and statistics".
The error is pretty damn huge... (Score:2, Troll)
Re:The error is pretty damn huge... (Score:2)
Depends what you are looking for. If your interested in global warming on the scale of 10E6 years, it would be certainly be a quite small timeframe.
The point is, this global warming is on a much smaller time-scale, more up to 10E2. (Actually, being on such a small time-scale is the problem).
Same point applies to local weather. The knowledge of global climate does not help us to predict, wether it rains in four days in Seattle or not.
>Fact is we aren't going to have an accurate snapshot
It does make as much sense as saying life doesn't exists because we don't have statistical evidence. On a certain scale, it may be correct. But on the scale, which currently interests us, it is not.
BTW, there are a geological study, which took geological cycles into account, which actually make much less optimistic.
Here is an essay [washington.edu]
PS: Hopefully, you don't involve some butterflies in the discussion.
Re:The error is pretty damn huge... (Score:1)
It isn't a small size. (Score:1)
Re:The error is pretty damn huge... (Score:2)
Believe what you want (Score:3, Insightful)
Re:Small Statistical Sample (Score:1)
To use your logic, a person who is fourty years old and has made over a million dollars in their life would not experience any undue financial effects from refusing to pay a few bills, or going on a credit-card spending spree of a few thousand dollars. After all, today is only 1/14600th of their life to date and shouldn't be that important, and a thousand dollars is only
Your arguments are irrelevant to the research being discussed. Try again.
Search on the net before trolling! (Score:1)
There a hundreds of good sites on the internet, try http://www.climate.org/ [climate.org] for an easy starter. Don't forget the Scientific American article [sciam.com]. And do some googeling [google.com].
Re:Search on the net before trolling! (Score:1)
More junk science which appeals to moronic nerds and their gut reactions.
Re:Search on the net before trolling! (Score:2)
First, it is a common misconception that global warming means, it will be warmer everywhere. This is not true, especially for Europe (see Gulf-stream, effect of lower density due to molted ice on).
Second, Greenland (named by Erik the Red to encourage his people [si.edu] to settle there, after discovering that a name like Iceland was detrimental to it's publicity) is still green in some areas (and there are still glaciers, too)).
Re:Search on the net before trolling! (Score:2)
And we never will unless we invent a time machine. Just like we don't know what the temprature in pluto is, just like we don't know how far the moon is.
Sure we can never KNOW what happened in the past but we can make pretty damned good guesses. For a long time atoms were guesses. Nobody KNEW that atoms existed for sure. Nevertheless it was a well accpeted theory and it was right.
You mean we're not omnipotent? (Score:2)
Dendracronology and ICE cores (Score:3, Interesting)
There have been studies of tree rings (Dendracronology) thousands of years old, the width of the tree ring tells you about the climate at the time it was growing.
So we have measured global tempretures back a few thousand years at least.
Then there's the ICE cores that can also tell you about global climate, they too go back thousands of years.
So you can say that in the past 50-100 years the climate has changed a stastically signifacant amount when compaired to the past 3-4 thousand years
failing that....
Rock strata can tell you somthing about climate going back 10's or hundreds of thousands of years.
Re:Dendracronology and ICE cores (Score:1)
http://www.ghcc.msfc.nasa.gov/MSU/hl_temp
Of course that isn't to say that we are still under going a short term warming trend since Europes mini ice age of the 17th and 18th centuries - didn't know about those, now did you ?
Thought not, better to buy into hysterical rhetoric then look at real stats.
Damn it would be cool (Score:1)
Yeah of course there would be problems with modern technology... I mean who was the bright person in Scotland who put the water pipes on the *outside* of the buildings? When it got to -25 celcius they encountered a few problems.
Re:Dendracronology and ICE cores (Score:2)
Re:Dendracronology and ICE cores (Score:2)
Lotts of different tree types (Score:2)
Some trees grow better when it's hot
Some when it's cold
Some when it's dry
etc.....
Re:Small Statistical Sample (Score:1)
Even more absurd than that from the article:
researchers seized upon the unique opportunity to compare the climate data for the clear skies on Sept. 11-14 against days of normal air traffic when jets streak the heavens with contrails.
They're comparing the temperatures over a range of 3 days! (article doesn't say to what they're comparing it to). Sounds to me like the simplest explanation is just a cold front.
Re:Small Statistical Sample (Score:1)
a minor technicality but a good point nonetheless
Re:Small Statistical Sample (Score:2)
I'm not sure exactly what you're saying. You may or may not be agreeing with this: We know that over long periods of time the climate changes dramatically, thus we expect over a contiguous section of 200 years there should be some sort of trend. Some people see a trend and shout that the sky is falling.
As with the polls that are done, if you poll 1000 random individuals across the country, the statistics work out something like you have an 80% chance of being within 10% of the true answer. There's a couple percent chance that their answer is significantly off because by chance they polled a cluster.
Hardly science.. (Score:1, Troll)
The "researchers" compared the weather of the 4 days following september 11th when most (non millitary) air traffic was suspended to the 'average' temperature, for those 4 days, of the past 30 years.
Anyone with even the smallest knowledge of statistics can tell you that this 'experiment' is absolutely non-scientific and the researchers admit it that global warming is likely responsible for most of the increase.
And anyone with even the smallest knowledge of scientific research can tell you that those results will never get published in any acientific journal since the basic requirement of all research today was not met. The "control group". There was no control group. No, the days before and after don't count as control group.
Apart from that, air traffic might have effect on weather. But my point is that we can't conclude from this "experiment" what that effect is. More (real) research is required.
Re:Hardly science.. (Score:1)
What they do have is an indication. If you are sceptical about this, you've never noticed that under certain weather conditions, the jet stripes do not easily disapear and form a sort of mist.
A dutch scientific magazine(Natuur&Techniek) had an article about that some months ago. It described a DIY experiment where you could determine the temperature at high altitudes from the type of aircraft and the width of the stripe. There were some nice pictures of a jet-stripe filled skie. I don't have it at hand, though. Did anyone else read it?
Re:Hardly science.. (Score:2)
A minor point, but important
Re:Hardly science.. (Score:2)
'acientific'? Freudian pseudo double-negative?
If you read the article, or even the
Re:Hardly science.. (Score:5, Insightful)
You didn't even have to RTFA - the write-up itself says, "but now their work has been published in Nature." You know, the well-known scientific journal [nature.com]?
Let me let you in on something...in investigations of the natural world - you know, that thing outside the lab? - you often don't get to have a formal control group. Cosmologists, for example, don't have a "control" universe to check against. Neither do meterologists have a "control" Earth to check against.
And if you had RTFA, you might see that what they were looking at was not the average temperature, but the temperature swing between day and night.
Saddest thing of all is that your post was modded up.
Re:Hardly science.. (Score:2)
Re:Hardly science.. (Score:2)
There is a joke non-existing journal eften refered to in the scientific world, it's called "Journal of non-repeatable results", and belive me "Nature" is one such journal..
And if you had RTFA, you might see that what they were looking at was not the average temperature, but the temperature swing between day and night
Read carefully: the difference between day and night is greatly affected by skyes.. Skyes, during night, act as a isolator, and keep the heat from escaping into space.
Many skyes = Colder day & hotter night = less difference between night & day
Few skyes = Hot day & cold night = more difference between day & night
Add the effect from greenhouse gases and your "data" is worthless.
Trust me, 4 days of data is absolutely insignificant and those results will never get published in any scientific journal !!
Re:Hardly science.. (Score:2)
Re:Hardly science.. (Score:2)
Re:Hardly science.. (Score:3, Insightful)
Nature is a well-respected peer-reviewed scientific journal. So your assertation is simply not true.
As for the rest of your post, I can't find any defintion of "skyes" other than a chain of islands off of Scotland, so I have no idea what you're talking about.
Almost sounds like you're talking about clouds - but of course, the whole fscking point of this research is how contrails affect cloud formation which then affects local climate.
Re:Hardly science.. (Score:2)
Wow, that is quite a lot of research material.
Cloud formation is one thing and it's effects on climate is another. But have a look at the article:
for Their conclusion: Without jets or contrails, the clear skies boosted the temperature swing between daytime highs and nighttime lows by about 3 degrees nationwide
So the 'swing' rose, indicating less skies ? (more skies would have decreased the swing)..
What is the theory here ? "publish crap and get some money "
Re:Hardly science.. (Score:2)
??? Pardon me, but last tie I knew they had thousands.
Neither do meterologists have a "control" Earth to check against.
And that, my dear watson, is why the earth is not studied as one big rock, but as many small, where you have 'control groups'
Re:Hardly science.. (Score:2)
The "researchers" did more than just compare weather reports:
However, instead of studying the lack of airborne jets during the FAA's three-day moratorium, Minnis considered the few aircraft that were in the skies -- military jets and transport planes.
In a usually packed air corridor around Washington, D.C., Minnis followed satellite images of a lone contrail drifting through the mid-Atlantic states on Sept. 12. The three days of grounded air travel provided him a unique opportunity to model the evolution of single contrails where normally scores or hundreds would be found.
He witnessed six contrails, each no wider than an airplane wing, evolve in a matter of hours into cloud banks that covered 20,000 square kilometers.
Yes, more research is required. Yes, it's pretty damn obvious that there is an effect. No, nobody knows if the effect is good or bad, but it is quite definitely there.
Re:Hardly science.. (Score:2)
There is no increase caused by jets.
Unfortunately, the article submitter obviously didn't understand at all what the article says -- first, it doesn't say earth's average temperature increases or decreases, it says the daily variation, i.e. the difference between night and day, changes. This is something that you can very well observe with just a few days of data.
Second, the researchers claim that the jets reduce the temperature range.
Re:Hardly science.. (Score:2)
To suggest that you can't learn anything from these situations reflects a misunderstanding about how science really works.
Absolutely, but where did I suggest that ?
My point was that there was *nothing* done to cancel out other factors or even explain how the numbers could have been affected. A real scientist would also have explained how the average of the same 4 days can change drasticly between years.
It is possible to skip the control group, sure. But in that case you have to repeat the experiment again and again, with and without the factor you are trying to measure (and you also have to include numbers from other factors), and then you calculate convergence for what you are trying to measure.
One measurement like this isn't worth piss, and yet it is presented as science.
Weather, not climate (Score:4, Informative)
More worriesome is that jet exhaust probably contributes proportionally more to the greenhouse effect than the amount of pollutants realeased would indicate, as it tends to be dumped high up, resulting in more greenhous gases ending up in the ozone layer than it would have had it been burned close to the ground.
/Janne
You're confusing your atmospheric problems (Score:3, Insightful)
Re:You're confusing your atmospheric problems (Score:1)
Jet exhaust? (Score:5, Insightful)
I love the "3 days isn't statistically significant" crowd. They had 3 days with no civilian air traffic. They observed military cargo flights leaving contrails that over a few hours turned into very large cloud formations.
Weather satellites observing six separate instances of these contrail to cloud formation growths is significant. There were more, but they spotted six instances where one plane flew through a clear area and made a cloud formation. Thet's pretty clear. Take 3 days without vast airplane formed cloud cover and, using all the other days with the manmade clouds as a control group, you can spot a 3 day blip with temperature variations of 3 degrees celcius more than all the days before and all the days after.
We had a 3 day window with wider variation in temperature extremes. We had a 3 day window with negligible air traffic. We have documented how well one airplane can make cloud cover. I'm not a global warming person or anything, but if it looks like a duck, swims like a duck and quacks like a duck, then you've got an agenda of your own if you won't admit that we've got a duck.
Saying that air travel affects our weather isn't panic or tree hugging, it's observation. We're not going to stop flying. We are affecting things, for good or bad we don't even know. I don't know how we'll be able to tell- that's where this information is insignificant. The effects are obvious, but whether these effects are actually bad is not something we can determine yet, if ever. Who knows, maybe more research on jet propulsion can end up stopping this. different insulation, directed airflow, who knows? Just because we don't fully understand something doesn't mean it doesn't exist. We may not have to, or even want to change anything. We just don't know enough about it yet.
Re:Jet exhaust? (Score:1)
100% ack. I am quite ashamed that such stupid discussions happens here on
I don't want to sound elitarian but if one is not a scientist or at least very familiar with the topic and statistics in general, one should just try to STFU^H^H^H^H^H learn by browsing the available [google.com] resources [google.com] instead of posting confused comments. As one wrote before: The saddest thing is that these postings got moderated up...
Cloud growth pictures (Score:1)
Yep, looks to me like the extra cloud cover from contrails could easily case a change in temperature. (pictures from a hokey site)
Re:Jet exhaust? (Score:1)
So... Who knows, maybe more research on jet propulsion can end up stopping this.
Might be a good thing (Score:2)
On more reason to get off the fossil fuel habit.
Except that you're assuming this effect is negative, which is by no means clear. If global warming turns out to be a significant problem, increasing the impact of airplane contrails is one of the more interesting technical hacks that has been proposed to fix the problem.
The relevant patent can be found here: Stratospheric Welsbach seeding for reduction of global warming [164.195.100.11].
Re:Might be a good thing (Score:1)
Except that you're assuming this effect is negative
He Said:
We are affecting things, for good or bad we don't even know.
Did you just get tired of reading and decided to reply? So typical
Re:Jet exhaust? (Score:2)
I fully agree. I wasn't trying to claim that 3 days without major flights over one country proved global warming. I wanted to slap everyone who claimed that 3 days wasn't a large enough study to show that we are affecting our environment. It seems that any discussion of man and earth immediately divides into two groups: those who think we're killing the earth and those who think we'll never run out of oil. They're both off base. I think we probably are causing global warming, but I'm not convinced. I am convinced that we're affecting the world, and that's what I was trying to get across. I was just trying to discount the large groups here that can't read a report with open minds; simply hailing it if it fits with their pre-conceived notions and blasting it if it doesn't.
And they all ran for the hills... (Score:2, Insightful)
Re:And they all ran for the hills... (Score:2)
That having been said, this article certainly wasn't alarmist. They said that they observed those effects unfor those conditions, and really have no idea at all how it might afect larger scale issues in the weather or climate.
As for "tribal segments" the real crap is believing that they are somehow specially adapted to their enviroment and cause no harm. The middle east used to have trees and vegetation, before ancient tribes chopped down all the trees for firewood and their goats ate all the grass. It's strongly suspected that a lot of the extinctions of big mammals about 10,000 years ago are due to the spread of ancient humans around the globe.
The only difference between "tribal" people and technologically advanced people is the rate at which we can make those changes to the enviroment.
It PREVENTS temperature variation (Score:5, Insightful)
First, they're not actually talking about exhaust here, they're talking about contrails, i.e. condensed water (clouds).
Second, the contrails, don't contribute to a temperature variation, they prevent it: "the clear skies boosted the temperature swing between daytime highs and nighttime lows by about 3 degrees nationwide."
Third, to all those who say this is laughable statistical analysis, it is not. They studied the weather, not long-term climate changes. And in fact it is well known that on days with a clear sky, it gets hotter during the day and colder during the night. I'm sure everyone of you already noticed that. The clouds prevent the sun from heating up the earth during the day, and during the night, they prevent the heat from radiating into space. The only thing that had not been researched so far was the effect of the (small) amount of clouds that are artificially created by jets every day. Surprisingly, it turns out that these clouds have the same effect that other clouds have.
Relating this to global warming is just speculation. Contrails are basically just clouds, and I don't think reducing variation in temperature between day and night will contribute to or reduce global warming. That just doesn't make sense, it's like saying rainy days contribute to global warming because there are so many clouds. Now I'm pretty sure that jets do contribute to global warming, but that's due to burning fuel, not due to creating contrails -- they could just as well burn the fuel on the ground, causing no contrails at all, and it would contribute to pollution of the air.
Re:It PREVENTS temperature variation (Score:1)
Re:It PREVENTS temperature variation (Score:2)
Well, yes, but I suppose that they compared their data not with that of cloudy days but with data from other, clear days during similar times of the year. I think what they're saying is not that the clear skys were caused by a lack of air traffic, but that the temperature variation was even higher than it normally can be expected on days with a clear sky. Of course, you can never prove that this wasn't just a coincident, but on the other hand the data does show an effect that you would expect anyway, so it does make sense to conclude that there is a relation between air traffic and temperature variation.
Of course, I'm not a meteorology expert, so I habe no idea how much data you would usually collect before drawing conclusions -- but that fact that this study has been published by Nature imho shows that at least it can't be totally bogus.
Re:It PREVENTS temperature variation (Score:2)
No, but your argument about how to define a "clear" day...
...makes sense. So I guess now I'll have to read the Nature article to find out :-)
You got it backwards! (Score:1)
When North American air traffic was grounded after Sept. 11, daily temperature variation INCREASED (hotter during day, colder during night) by around 3 degrees Celsius. That's a big difference, globally speaking.
Read the Abstract (Score:4, Informative)
I'll one more, very important, link to the mix. You can read the abstract [nature.com] for free. Reading the paper itself is not free, unless you count going to your local university library for the dead tree copy as free. Before anyone else comments on the science behind this, please at least read the abstract, and hopefully have the knowledge to pass at least one introductory statistics course.
If you don't want to affect the environment... (Score:2, Funny)
Re:If you don't want to affect the environment... (Score:1)
Re:If you don't want to affect the environment... (Score:2)
Of course... (Score:1, Funny)
Sheesh, what are we paying these people for?
And this is news? (Score:1)
Aeroplanes definitely cause a lot of pollution and affect the atmosphere quite badly.
About as close to proof as nature lets you have (Score:1)
Another thing they didn't factor in (Score:3, Interesting)
Maybe they didn't measures what they thought they were.
NASA contrail images (Score:3, Informative)
Here's everything that I can find in 5 minutes, it comes close to showing what I saw once. (I swear it was from the Terra satelite, but I can't find it right now)
http://www.wrh.noaa.gov/Flagstaff/science/contrai
http://visibleearth.nasa.gov/cgi-bin/viewrecord?2
http://www.wrh.noaa.gov/Flagstaff/science/contrai
http://visibleearth.nasa.gov/cgi-bin/viewrecord?5
http://visibleearth.nasa.gov/cgi-bin/viewrecord?4
Ships put out an amazing amount of water vapour, and photos of the Western Seaboard have shown huge numbers of ship generated cloud banks off of San Francisco. Here's one example:
http://visibleearth.nasa.gov/cgi-bin/viewrecord?1
Re:Perhaps we have a bigger problem... (Score:1)
Re:Perhaps we have a bigger problem... (Score:1)
Re:Touching the surface (Score:5, Insightful)
Are you kidding? You're asking every single person in the world to roll back their technology over 100 years. How would ANYONE get around? It has nothing to do with addiction to lifestyle, it has to do with that technology being necessary for most people's LIVES, since so few people have any alternate means of transportation. Since the advent of the supermarket, corner markets no longer exist (sure, convenience stores exist, but have you ever tried to actually eat a meal from a convenience store that consists of more than chips and beer?). The majority of the population would have a hard time getting to and from a grocery store, typically located several miles from their home. For most people, walking that far would be an all-day proposition, or out of the question entirely. Not many people have a horse and buggy anymore, and a bike that isn't set up to carry a load is woefully inadequate to the task of hauling large quantities of groceries. Not to mention the fact that farmers wouldn't be able to harvest their crops without their petroleum-burning tractors, combines, etc, so even after your little experiment was over, people STILL couldn't eat. Few people would be able to get to work, since few people live within a short distance of their jobs (the car made suburbs possible). Do you consider natural gas- or oil-fired power plants to be petroleum based engines? If so, we wouldn't have much electricity either. In short, the economy would completely shut down, thousands of people would die, and your "interesting study" would have a disastrous effect on the world.
Re:Touching the surface (Score:2)
Now if life were to change such that cars were no longer economical or possible for some reason, i would look into moving or changing jobs. However for the sake of a one month experiment, no way.
And while i've heard that it's different in some other countries, in America at least without gasoline everyone who lives in a city or major suburbs would have to move. With out current infrastructure we don't have the means to deliver the food we produce to the people who eat it without petroleum products. Most people in cities or suburbs may be within walking distance of a supermarket, but it doesn't do much good if the supermarket doesn't have any food.
Sure we could fix all those issues, between alternate fuel supplys and alternate methods of transporation, but it's a bit too entrenched to be refered to as just a lifestyle. Whether or not i can go down to the mall and buy a cd or some new clothes is a lifestyle, the method by which the food necessary to my life is delievered isn't so much.
Re:Touching the surface (Score:2)
Re:Touching the surface (Score:2)
And before (nearly) everyone had a car, everything everyone needed to survive was within walking distance. Work, the grocery store, the drug store, the doctor, EVERYTHING. I live 12 miles from where I work. I live 4 miles from the nearest grocery store. I'm guessing here, but I probably live about 5 miles from my doctor.
Look at monkeys, and tell me I'm wrong.
You're wrong. Last I knew, monkeys lived within inches of their food. Humans did too, when we were all subsistence farmers or hunters. Now a lot of us live in cities. How much food do you see being grown within most metropolitan regions of the US?
I don't know about you, but walking a few miles to a store doesn't take all day.
No, it doesn't, for me and (presumably) you. But ask the average American (whose idea of exercise is to lift the remote off the table and walk to the bathroom a couple times a day) to walk 3 miles to a grocery store, then 3 miles back while carrying 30 pounds of groceries, and it could take a while.
you'd be forced to produce your OWN [food].
Now that's a funny thought. I live in a city. Where do you propose I grow this food? Where do you propose I get the seeds? Etc.
Those who can't care for themselves are already cared for by others, so the disabled and elderly have their bases covered for the most part.
Both my grandmothers are in their 80s, neither are cared for by others, and neither would be able to walk to the grocery store, let alone back with an armful of groceries.
Our society is not so unethical that in such an experiment, we would just abandon those in need.
No, but when I'm spending 8 hours a day at work, 6 hours a day walking back and forth to work, and a few hours walking back and forth to the grocery store, I have little time to walk 150 miles to bring my grandma groceries.
First, I didn't mention the world.
From your original post: A more interesting study would be to stop all petroleum based engines for a month. Since the US does not have a monopoly on petroleum based engines, I merely assumed you meant the world. I apologize.
Second, if my experiment came about from an uncontrollable event, you would probably be the first to die.
Ha. Not likely. I'm a backpacker, so I know my edible plants, and I'm in excellent shape. It's the fat ignorant slobs that mostly populate the country that I think would die.
Re:Touching the surface (Score:2)
and probably good eatin' too.
Tree-hugger paranoia, of course. (Score:2)
You have a plane flying around with a nuclear reactor on board. First, you have to keep it cool and dump the excess heat. Whether that'd be the equivolent to a coventional jet engine or more, I'm not sure, but you're basically coming around to the same problem. Second, you have a nuclear reactor flying around above peoples heads. Nevermind that you can make it damn near fool-proof and crash resistant (like nuclear warheads that'll withstand impacts the rest of the airframe won't), environmentalist propaganda would paint pictures of meltdowns in the sky and the scattering of nuclear material everywhere. The last reason alone will guarantee you won't see em in unclassified aircraft anytime soon. That, and about the only real advantage nuclear will gain you (after the signifigant increase in weight) will be endurance to stay aloft as long as the reactor provides power. An intresting point to be made would be that in a crash you wouldn't have to worry about a fiery impact scortching miles on end. Even if the reactor somehow "cracks", a 747 won't have as large a pile to draw power from. Sure, radiation would be a problem, but more than a fiery ball of death?
Have you forgotten about hijackers? (Score:3, Interesting)
Oh please. Even if the reactor is made 100% safe so that a skyscraper impact spreads no radiation, how do you prevent the plane from being hijacked and flown to an "axis of evil" nation that wants to get its hands on the plutonium? A nuclear plane could fly around the world many times without refueling, so this is an issue even for domestic flights. A nuclear-powered commuter flight from Boston to New York would easily be in range of North Korea. How are you going to guarantee that this won't be a problem? With computer-enforcement of no-fly zones? Or by arming pilots?
The tight export controls on a nuclear plane would be just one of the many headaches that an aerospace manufacturer would face, and while those caused by "tree-hugger" sensibilities are among them, there are many others. Ideology aside, safety and nonproliferation are serious problems that need to be addressed in any project of this nature. Nuclear planes are not cost-effective to manufacture. And unlike nuclear submarines, they do not solve any compelling problem that is left unaddressed by their conventional counterpart. Even the military, which comissioned the manufacture of nuclear submarines during the Cold War and was not as affected by "environmental propaganda", never did the same for the nuclear airplane.
Re:Have you forgotten about hijackers? (Score:2)
Re:planes farting affects the weather (Score:2)
I guess I should cancel my upstart, Burrito Airlines.
Re:planes farting affects the weather (Score:1)
Re:Local fauna - zilch (Score:1)
I'd love to know where you came up with that crock of baloney.