How contrails are affecting climate and contributing to Global Dimming

I thought it was high time that ATS started discussing the very real affects of contrails in regards to Earth's climate.

Contrails, like clouds, seem to come in a variety of shapes and sizes. Some disappear very shortly after they're formed by the aircrafts. Some persist long after the planes are out of sight. The persisting ones will often dissipate to form cirrus clouds that cause the sky to appear foggy or cloudy. Some persisting contrails form grids and other unnatural designs. People have speculated many things about these persisting trails. Some believe they're reflecting sunlight back into space, which has been discussed by scientists as a valid means of Solar Radiation Management, or SRM, technology. Some people believe that these persisting trails contain toxins that are building up in the water, soil, and living bodies.

No matter what is speculated, the fact of the matter is is that scientists are confident that the persisting trails are affecting the climate. This topic is widely discussed and accepted as a problem among the scientific and meteorological communities.

articles.cnn.com...:TECH

The thin wisps of condensation that trail jet airliners have a significant influence on the climate, according to scientists who studied U.S. skies during a rare interruption in national air traffic after the September 11 terrorist attacks.

During the three-day commercial flight hiatus, when the artificial clouds known as contrails all but disappeared, the variations in high and low temperatures increased by 1.1 degrees Celsius (2 degrees Fahrenheit) each day, said meteorological researchers.

In some ways, contrails differ from their natural brethren. Cirrus clouds let less heat out than in overall, producing a net increase in the Earth's temperatures, according to climate scientists. With contrail clouds, they said they are not so sure.

"Contrails are denser and block sunlight much more than natural cirrus clouds," said Travis, who with colleagues reported the findings this week in the journal Nature.

"And contrails are much more prevalent when the sun is out," he said. "When this is factored in, there is a possibility that they offset global warming, and this is what we are trying to determine now."

newswithviews.com...

NASA research studies show that increasingly persistent jet contrails may turn into man-made clouds (or white haze), that are “…trapping warmth in the atmosphere and exacerbating global warming…” NASA (2005 Newsletter), goes on to state their studies reveal that “…Any change in global cloud cover may contribute to long-term changes in the Earth’s climate. Contrails, especially persistent contrails, represent a human-caused increase in the Earth’s cloudiness, and are likely to be affecting climate and ultimately our natural resources…”

3- NASA, in an October 2005 newsletter states: “…A recent investigation focuses on how aircraft can avoid creating vapor trails, also known as contrails. These spindly threads of condensation may not seem important but some persist for hours and behave in the same way as high altitude cirrus clouds, trapping warmth in the atmosphere and exacerbating global warming…" NASA October 2005

www.wrh.noaa.gov...

Contrails are a concern in climate studies as increased jet traffic may result in an increase in cloud cover. Several scientific studies are being conducted with respect to contrail formation and their climatic effects. Cirrus clouds affect Earth's climate by reflecting incoming sunlight and inhibiting heat loss from the surface of the planet. It has been estimated that in certain heavy air-traffic corridors, cloud cover has increased by as much as 20%. Since contrails can spread out and essentially become cirrus clouds, it is felt that contrails may affect the planetary climate in similar ways. Other studies are underway to better understand the role that jet exhaust itself plays in modifying the chemistry of the upper levels of the atmosphere.

www.albionmonitor.com...

And the short answer, according to Steven Ackerman, a University of Wisconsin professor of atmospheric science, is that jet exhaust plumes -- commonly referred to as contrails -- can indeed influence regional climate.

Addressing scientists at a meeting of the American Geophysical Union, Ackerman detailed the results of a year-long study of contrails and their fate in the upper atmosphere.

There are two broad areas of concern when it comes to contrails, he said: One, are they changing the chemistry of the upper atmosphere? And, two, are they responsible for increased regional cloud cover, a phenomenon that could disrupt the radiation balance, and thus the climate, of a region?

Ackerman and his colleagues, supported by the National Science Foundation and NASA, have been focusing on the latter question for the past year. The Wisconsin scientists are exploring the geometry and fate of contrails in a set of field experiments employing four different aircraft. One lays down a contrail, the second tailgates and samples the contrail at close range, the third observes from an intermediate distance and the fourth high-flying aircraft looks down on the contrail much like a satellite would.

And, he said, contrails appear to be different than other types of ice crystal-based clouds, such as thunderstorms, mountain wave clouds and cirrus clouds. The field experiments indicate that contrails process infrared radiation differently. Those differences, Ackerman suspects, arise from the varying cloud particle sizes and shapes in contrails.

Clouds of all kinds, including contrails, affect weather and climate because they can both reflect the sun's radiation back into space, and trap the infrared radiation emitted by the surface of the Earth.

"If contrails spread out, then they can modify the energy balance of a region," Ackerman said. "But how it affects the energy balance is not just a function of how much cloud is up there, but what kind of cloud is up there."

As you can see, there is more than enough evidence that contrails are a threat to the Earth's climates and ecosystems.

Now, those who have studied geoengineering and have explored the many topics of discussion among climatologists are well aware that a type of Solar Radiation Management (SRM) referred to as Global Dimming has been decided to be the least expensive as well as the most reversible option available to combat global warming. But, there has been no green light documented and it's widely accepted that SRM has not been deployed, which leads me to the next piece of the puzzle: Does Global Dimming need a concrete OK/Go Ahead since it's happening already because of regular and increasing air traffic?
www.globalissues.org...

On January 15, 2005, the BBC broadcast its weekly acclaimed Horizon documentary. This one was about a dangerous phenomenon called Global Dimming.

This reduction of heat reaching the earth is known as Global Dimming.

Given the above evidence, at this time we can safely say that Global Dimming is happening whether our "leaders" have officially announced it or not.

I have never seen con or chem trails in Toronto, Canada. The skies are clear here. So I don't know about the global effect.

reply to post by NewerBeing


Please read the links. It is happening globally.
No place on Earth is immune to contrails.

reply to post by Afterthought


Never ever get contrails where I live.

But I'm not under any flight paths either, so I wouldn't expect any...and for SRM to work it needs to be global and since I live in one of the hottest countries in the world and am not seeing any contrails I'm 100% confident there is no concerted effort to geo-engineer.

Here's some more evidence to chew on:

ramblingsdc.net...

Research by many workers and in a number of countries has indicated that the amount of solar energy reaching the Earth's surface has been gradually falling for the past fifty years or so.

Aircraft contrails are responsible for some global dimming. (All commercial flights were stopped for a few days following the New York Twin-Towers 2001/09/11 incident. Researchers discovered some unexpected changes associated with the sudenly greatly reduced contrail density.) Contrails also decrease the diurnal temperature variation; that is, they cause nights to be a little warmer and days to be a little cooler than they would otherwise be.

The dimming of sunlight may well cause reduced evaporation from the oceans with consequent reduction in rainfall. There have been suggestions that the effect may be responsible for droughts in the Sahel in the 1970s and 1980s. It may also have a disastrous impact on Asian monsoons.

Research has indicated that since 1950 the USA has lost 10% of its sunlight, the British Isles 16%, and some states of the former USSR over 30%. The largest reductions have taken place in northern hemisphere mid latitudes.

news.bbc.co.uk...

Dr Stanhill called it "global dimming", but his research, published in 2001, met a sceptical response from other scientists.

It was only recently, when his conclusions were confirmed by Australian scientists using a completely different method to estimate solar radiation, that climate scientists at last woke up to the reality of global dimming.

Because the particles seed the formation of water droplets, polluted clouds contain a larger number of droplets than unpolluted clouds.

Scientists are now worried that dimming, by shielding the oceans from the full power of the Sun, may be disrupting the pattern of the world's rainfall.

There are suggestions that dimming was behind the droughts in sub-Saharan Africa which claimed hundreds of thousands of lives in the 1970s and 80s.

There are disturbing hints the same thing may be happening today in Asia, home to half the world's population.

"My main concern is global dimming is also having a detrimental impact on the Asian monsoon," says Professor Veerhabhadran Ramanathan, professor of climate and atmospheric sciences at the University of California, San Diego. "We are talking about billions of people."

www.contrails.nl...

The word Contrail stems from 'condensation' and 'trail'. Aviationsmog (that's what it really is) is caused by airtraffic at great heights. Each day, jetengines of airplanes dump vast amounts of water (ice), CO2, soot particles (condensation nuclei), aërosols and chemical substances. Airtraffic thus not only alters the properties of the higher regions of our troposphere but also all the regions below, right down to groundlevel. This extra layer of man-made high-altitude smog probably infuences weather, climate and the quality and quantity of the sun's radiation that reaches the surface of Earth ("global dimming."). Aviation-smog is responsible for more clouds, rain, drought, bigger hailstones (megacryometeors), a stronger greenhouse effect (global warming), and, maybe, even gives extra power to hurricanes. Still, aviation-smog does not get the scientific and political attention it deserves.

"Beautiful weather today, with a full sunshine. There are some high veilclouds, but they are thin, so the sun can easily shine through them," (Public Broadcast NOS, May 26th, 2005.)

The picture above shows the reality: Aviation smog covered the sky that, without aviation, would have been cloudless and blue. Meteorologists rather ignore facts that are bad for their business.

Telescopes 'worthless' by 2050.
Ground-based astronomy could be impossible in 40 years because of pollution from aircraft exhaust trails and climate change, an expert says. Aircraft condensation trails - known as contrails - can dissipate, becoming indistinguishable from other clouds. If trends in cheap air travel continue, says Professor Gerry Gilmore, the era of ground astronomy may come to an end much earlier than most had predicted. Aircraft along with climate change will contribute to increased cloud cover. (Paul Rincon, BBC News.)

Are Skies Dimming Over Earth?
Scientists have long argued that human activity may be warming the Earth through a process known as the greenhouse effect. Now studies show we may also be having a different kind of impact: global dimming. Researchers have found the amount of sunlight hitting the ground over China dropped by 3.7 watts per square yard over the last 50 years. (ABC News- February 9, 2006)

Veil clouds.
I love learning new terms.

To those who are stating that you never ever see contrails in your skies, please try to emerge from your little crevace in the world and try to turn your thoughts to those who are reporting much persistent contrail activities.

For example, just because you're not starving doesn't mean that starvation is not happening somewhere in the world.

It's very egotistical to not be concerned about something just because it's not happening to you directly.

Thats very disingenuous, blaming the effect of global cooling on contrails from aircraft that today are many times more efficient and produce much less polution than their counterparts of yesteryear.
Contrails are very rarely supported by the atmospheric conditions into lasting more than a few minutes at most, it used to be a very rare occurence to see a contrail last for more than ten minutes.
We are not witnessing "Contrails" but something else, designed for Geo-engineering or worse.
How can you start a topic about "Contrails", present hypotheses that they are changing the global temperature, and not present the information, well documented information, of the aircraft borne machinery and constituent chemicals of admitted "Geo-engineering" programs that are designed specifically to do the very thing you talk about.

A very poor attempt at veiling the truth of chemtrailing, geo-engineering, behind the mundane facade of "Contrails".

reply to post by Afterthought


It's the other way round mate, those stuck under air corridors need to get out of their small little world and realise that just because they constantly get contrails doesn't mean everyone else gets them.

Do you see anyone denying contrails are real? No. Yet I constantly see people saying that "planes are spraying trails in front of the sun", they can't grasp a simple concept called PERSPECTIVE.

How hard is it to understand that what you see will be totally different to what someone else sees??

And also, what is the point of tackling GLOBAL warming by carrying out SRM in some places but not others...?

That's like putting a screen door on a submarine...utter stupidity.

Finally, if there was a concerted effort to carry out SRM, which is designed to simulate the effects of a large volcanic eruption where the entire planet gets a layer of ash and dust in the atmosphere and therefore cooling the planet a fraction of a degree, why is the stratosphere is as clear as ever?

www.abovetopsecret.com...

reply to post by The X


While I appreciate your contribution, this is NOT a veiled attempt to avoid the issue of what I call CONtrails, which is what I consider to be persisting contrails and are indistinguishable from natural cirrus clouds.

If we are to educate others about the dangers involving CONtrails, we must first demonstrate that geoengineering is happening already in the form of global dimming. Once people are aware that global dimming is indeed happening, this will open the door to discussing the substances believed to be in CONtrails.

I have engaged in several heated discussions involving geoengineering and climate engineering. Those who do not believe that this type of geoengineering is being conducted need to know that the Royal Society and other groups don't have to officially announce that global dimming is being conducted because it has been happening for several decades already. To put it in a nutshell, we need to stop waiting for our "leaders" to publically announce that climate engineering is happening. We need to be able to make our own minds up and realize that treaties involving global geoengineering cannot be honored because geoengineering has been happening way before the treaties were inked.

reply to post by The X


No, there is not "something else" going on......it's "nothing else".

There is no "global dimming" occurring, either. The sources that are the basis for this thread are grossly over-stated.

Even for those days when air traffic was stopped, post-9/11 (in the USA only, I hasten to add) the studies themselves noticed a tiny, tiny, tiny 1.1 degree Celsius difference in the variation of temperature.....on an average, nationwide.

This is meaningless, with only a few days' worth of sampling......not even long enough to have an established baseline for reference.

I mean, just look at the extremely mild winter we just had.....due to effects from El Nino in the Pacific Ocean, and the resulting changes in jet stream patterns, among other things. THAT certainly "threw off" the statistical temperature averages!

"Global dimming" is a fallacy.

reply to post by ProudBird

There is no "global dimming" occurring, either. The sources that are the basis for this thread are grossly over-stated.

Really? If you honestly feel this way, please back up your statement by kindly indicating which
source(s) in the Op is/are grossly overstating this phenomenon.

Most of the articles on Global Dimming ore out of date. The dimming reversed a while ago with the effects of the clean air acts and lack of major volcanic eruptions.

www.sciencemag.org...

Variations in solar radiation incident at Earth's surface profoundly affect the human and terrestrial environment. A decline in solar radiation at land surfaces has become apparent in many observational records up to 1990, a phenomenon known as global dimming. Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s.

Contrails do have an effect though, see this 1980 news report:

reply to post by Uncinus


Thanks for offering up that info, but I'm unable to visit the entire article. Is there another source you can provide that I can read that isn't just an abstract of an article?

Here's what I got when I clicked 'Read full article':
www.sciencemag.org...
I really dislike how websites want you to register in order to gain more education.

I'd like to add though that it's nice we can discuss the environmental effects of contrails. I did read that scientists are trying to come up with a way for planes to not leave contrails, but I don't believe a method has been created yet.

reply to post by Afterthought


See the Wikipedia Article:
en.wikipedia.org...

Links to a full article from NASA:
www.nasa.gov...

I hate the academic paywalls too. It should be free for everyone.

This PPT gives more details on the Wild study:
irina.eas.gatech.edu...

reply to post by Afterthought


Here's the full Wild paper from Science:
nml.yonsei.ac.kr...

Lots of other papers on the recent brightening:
scholar.google.com...

reply to post by Uncinus


Thanks for those links.
I'm going to check them out now and comment after I've reviewed them all.

reply to post by Afterthought

I agree with you that jet exhaust is a real toxic problem and shouldn't be pooh poohed as in 'it's just water vapor' but the contrail of yesteryear that occasionally turned into cirrus is not the same as the chemtrail of our times as observed in mid-latitudes. The articles themselves quote researchers saying that the particles being used are creating clouds that behave differently.

9/11 study: Air traffic affects climate

"Contrails are denser and block sunlight much more than natural cirrus clouds," said Travis, who with colleagues reported the findings this week in the journal Nature. "And contrails are much more prevalent when the sun is out," he said.

Are Jet Plane Trails Affecting the Climate?

And, he said, contrails appear to be different than other types of ice crystal-based clouds, such as thunderstorms, mountain wave clouds and cirrus clouds. The field experiments indicate that contrails process infrared radiation differently. Those differences, Ackerman suspects, arise from the varying cloud particle sizes and shapes in contrails.

Contrail development, persistence and behavior is fuel particle specific.

Contrail cirrus supporting areas in model and observations

Contrails form and persist dependent on the surrounding moisture, temperature and pressure fields and on fuel and aircraft specific variables.

Why even have contrails unless they are chemtrails? The technology exists to eliminate them.

Notes on the Subject of Contrails

In 1994 the government awarded a $16 million contract to the Northrop Corporation to fine-tune stealth bombers in a number of ways. One retrofit involved the installation of five “contrail management systems.”

Contrails And The Dark Side

In 2000, Air International magazine published an article about the B-2, and explained how it was that the B-2 didn't produce contrails. "As for elimination of contrails (normally a giveaway, even for a stealth aircraft), the USAF said chlorofluorosulphonic acid was injected into the jets to eliminate contrails."

But the USAF later told reporters that it was done by "regulating exhaust temperatures." Air International considered this "nonsense," because: "contrails are ice crystals from water vapor left when hydrocarbon fuel is burned, and can never be eliminated by 'regulating exhaust temperatures.'"

Guesswork and denials aside, one commentator believes he can explain contrail-less military aircraft. David Hambling, author of Weapons Grade, says that the technology for reducing contrails has been available for some time. He refers to a technology called "plasma aerodynamics," that was first developed and researched by the Russians.

"According to the patents, it has additional benefits too - it can muffle the noise produced by engines as well as preventing contrails from forming. The only people not enjoying its benefits are the civilian taxpayers who funded it in the first place."

reply to post by luxordelphi

I agree with you that jet exhaust is a real toxic problem....

Well then, you might want to insist that all airplanes are towed to the end of the runway, and engines only then started, just before takeoff.

And, have you ignored the jet exhaust from takeoff, and during climb (when contrails don't form)?

Or, from descent, and during the level-offs and intermediate parts of the arrival, when the SAME exhaust is still being emitted....and, again, contrails don't form?

Be logical, and try to learn about the topic before making claims that a few hundred jets and their "exhaust' is a "toxic problem", whilst ignoring literally millions of cars and trucks and motorcycles and mopeds and lawnmowers (etc), here on the ground!!

reply to post by luxordelphi

Why even have contrails unless they are chemtrails? The technology exists to eliminate them.

No....what you posted were mention of attempts to mitigate CONTRAILS!! Not imaginary "chemtrails"!

Contrails......even the "stealth" airplanes, like the B-2, still use jet engines, and the "give-away" and 'tell-tale' that destroys their "stealthiness" are the contrails that they naturally form, when conditions are suitable for contrail formation!!

This is so simple to understand!

Originally posted by luxordelphi
Why even have contrails unless they are chemtrails? The technology exists to eliminate them.

Notes on the Subject of Contrails

In 1994 the government awarded a $16 million contract to the Northrop Corporation to fine-tune stealth bombers in a number of ways. One retrofit involved the installation of five “contrail management systems.”

Why? Because they are expensive.

Ironically one the the technologies (the injection of acid, tested my the military, but abandoned as impractical due to the corrosive effects) would turn the contrail from a harmless cloud of ice crystals into an actual "chemtrail", albeit an invisible one.