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Study: Jet Exhaust Affects Weather
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.
All the concrete in the airports have been doing this for years. Ever hear of urban heat islands?
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
Trust the Computer. The Computer is your friend.
Cell phones don't cause brain cancer. Does this mean researching the effect of high voltage power lines is a waste of time?
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.
The good and new comes from no quarter where it is looked for, and is always something different from what is expected.
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 ?
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.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
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.
I spent a year in Iraq looking for WMD and all I found was this lousy sig.
A more interesting study would be to stop all petroleum based engines for a month (including jets), and measure the impact on the climate...Alas, this will never happen, because people are addicted to their lifestyles.
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.
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.
Sig (appended to the end of comments I post, 54 chars)
When slashdot selected the same story just three short days ago, they also linked to an NPR story and a blurb on the nature website.
I'll one more, very important, link to the mix. You can read the abstract 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.
Slashdot is jumping the shark. I'm just driving the boat.
You know, you might laugh about it, but if you lived somewhere where even a slight variation in sea level is of major concern, say Venice or Bangladesh, then I doubt you'd be so flippant about the issue.
/. stories that have an environmental slant to them have nothing positive to add to the debate and prefer joking about the subject rather than even admit that there might be a serious problem that needs to be addressed.
/. if not elsewhere, it's fashionable to be worried about the chances of the human race being wiped out by a giant asteroid collision but it's laughable to suggest that we (and countless other species) may be at danger because of our own reckless behaviour.
(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
"Accept that some days you are the pigeon, and some days you are the statue." - David Brent, Wernham Hogg