posted on May, 6 2012 @ 08:47 AM
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.
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."
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
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
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
On January 15, 2005, the BBC broadcast its weekly acclaimed Horizon documentary. This one was about a dangerous phenomenon called Global
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.