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Air
Traffic
At high altitudes, the emissions of
aerosols and particulate matter influence the radiative nature of the
atmosphere which result in increased cirrus clouds and more persistent
contrails
NASA ARC Image
Contributing to Climate Change and Ozone Destruction
1
round trip from NY
to LA or Trans Atlantic round trip = 2,000 pounds of CO2
In
a year air travel releases 600 million tons of carbon dioxide into the
atmosphere
Contrail Streaming From An
Aircraft
By the
year 2050, increased flights by jet airplanes will impact global climate
through the greater number of contrails they will produce, according to a
study completed in 1999 and published in The Journal of Geophysical Research Letters.
Contrail Formation
University of Alaska Image
A research
team of American and German scientists, headed by Patrick Minnis of the NASA
Langley Research Center in Hampton, Virginia, reports evidence that contrails cause a
warming of the Earth’s atmosphere. Currently their impact is currently
small as compared to other greenhouse effects. They predict, however, that
it may grow by a factor of six over the next 50 years. The researchers
emphasize that these are conservative estimates, which take into account
only the thicker contrails that can be readily observed.
Contrails
Thinner contrails
and contrails that have developed into natural-looking cirrus clouds also
affect climate, but their impact cannot yet be predicted. Other factors that
would play a role include natural cloud cover, overlapping of contrails, and
size of the ice particles that form in them. They call for further research
into the full extent of current contrail coverage and the specific effect of
contrails in forcing climate change.
Several
scientific studies have suggested that aviation may contribute to
detrimental chemical changes in the atmosphere (particularly ozone content),
as well as possible climate modification. The most widely accepted
assessments are those conducted by United Nations (U.N.) scientific
organizations. Ozone trends are monitored by the United Nations Environment
Programme (UNEP) and the World Meteorological Organization (WMO).
NASA
Wake Vortex experiment forming of contrails
Air
traffic and, therefore, contrails, are not evenly distributed around the
globe. They are concentrated over parts of the United States and Europe,
where local warming reaches up to 0.7 watts per square meter, or 35 times
the global average. The ghostly white trails
following airplanes and rockets through the sky, called contrails, are
probably adding to global warming, according to scientists at NASA’s
Langley Research Center, Hampton, Va. The contrails often turn into cirrus
clouds, a thin, wispy type of cloud made of ice crystals. The most common
form of high-level clouds are thin and often wispy cirrus clouds. Typically
found at heights greater than 20,000 feet (6,000 meters), cirrus clouds are
composed of ice crystals that originate from the freezing of super cooled
water droplets. Cirrus generally occur in fair weather and point in the
direction of air movement at their elevation. While some clouds tend to help
cool the globe and negate the affects of global warming, thin cirrus clouds
are heat trappers, holding in more heat than they reflect back into space.
NASA Space Shuttle view from space of cirrus clouds over Saudi Arabia
Contrails are
human-induced clouds that only form at very high altitudes (usually above 8
km) where the air is extremely cold (less than -40°C). If the air is very
dry, they do not form behind the plane. If the air is somewhat moist, a
contrail will form immediately behind the aircraft and make a bright white
line that lasts for a short while. Persistent contrails form immediately
behind the airplane in very moist air. Persistent contrails can exist
long after the airplane that made them has left the area. They can last for
a few minutes or longer than a day. However, because they form at high
altitudes where the winds are usually very strong, they will move away from
the area where they were born. Persistent contrails are those most
likely to affect climate.
Present commercial
aircraft fly at altitudes of 8-13 km. The emissions from such air traffic
can change the atmospheric composition: Directly: by emitting carbon dioxide
(CO2), nitrogen oxides (NOx = NO + NO2), water vapor, hydrocarbons,
soot, and sulfate particles. Indirectly: by a chemical reaction chain
similar to smog-formation the greenhouse gas ozone (O3) can be formed. In
this reaction chain nitrogen oxides act as a catalyst under the influence of
sunlight. As a result of these chemical reactions also the concentration of
methane (CH4), another greenhouse gas, decreases. These changes can have
effects on climate: Ozone, CO2, and water vapor are greenhouse gases and
their increase has a warming effect. Methane is also a greenhouse gas and
its decrease has a cooling effect. Aerosols (sulfate particles, soot) could
have a cooling effect. Contrails formed due to the emission of particles and
water vapor can increase the cloud cover in the upper troposphere. This may
result in a cooling or heating depending on the size and optical depth of
the ice crystals of which the contrails consist. Presently it is believed
that contrails lead to a net warming effect. There may be changes in
(non-contrail) upper level clouds: Most contrails decay after minutes to
hours, but some continue to exist and are then not distinguishable from natural cirrus clouds .
Schematic
based on DLR German Aerospace Center graphic and text
Schematic
of aerosol and contrail formation processes in an aircraft plume and wake as a
function of plume age and temperature. Reactive sulfur gases, water vapor, chemi-ions,
soot aerosols, and metal particles are emitted from the nozzle exit planes at
high temperatures. H2SO4 increases as a result of gas-phase oxidation processes.
Soot particles become chemically activated by adsorption and binary
heterogeneous nucleation of SO3 and H2SO4 in the presence of H2O, leading to the
formation of a partial liquid H2SO4/H2O coating. Upon further cooling, volatile
liquid H2SO4/H2O droplets are formed by binary homogeneous nucleation, whereby
the chemi-ions act as preferred nucleation centers. These aerosols grow in size
by condensation and coagulation processes. Coagulation between volatile
particles and soot enhances the coating and forms a mixed H2SO4/H2O-soot
aerosol, which is eventually scavenged by background aerosol particles at longer
times. If liquid H2O saturation is reached in the plume, a contrail forms. Ice
particles are created in the contrail mainly by freezing of exhaust aerosols.
Scavenging of exhaust particles and further deposition of H2O leads to an
increase of the ice mass. The contrail persists in ice-supersaturated air and
may develop into a cirrus cloud. Short-lived and persistent contrails return
residual particles into the atmosphere upon evaporation. The scavenging
timescales are highly variable and depend on the exhaust and background aerosol
size distributions and abundances, as well as on wake mixing rates
NASA
Graphic from The TERRA Program
Clouds
play a complex role in the Earth's radiation budget. Low Clouds reflect much
of the sunlight that falls on them, but have little Effect on the emitted
energy. Thus, low clouds act to cool the Current climate. High clouds
reflect less energy, but trap more of The energy emitted by the surface.
The
Atmospheric Effects of Aviation Project For
the past 10 years NASA has held a conference on The Atmospheric Effects of
Aviation Project (AEAP). Several hundred researchers from around the world
attend annually. In 1997 Researchers from NASA
Langley Research Center in Hampton, Virginia, presented evidence that
contrails are contributing to global warming and causing local effects over
areas with heavy air traffic. This was reported by Jim Scanlon a journalist in
attendance at the conference. He also reports that Fred Singer held a session
where he presented a session that argued that the steady increase in air traffic
for the last 20 years was responsible for the nighttime warming detected over
North America.
NASA
The Atmospheric Effects of
Aviation Project (AEAP) consists of two major efforts to assess the effect
of aircraft on the atmosphere. The Atmospheric Effects of Stratospheric
Aircraft (AESA), sponsored by the High-Speed Research (HSR) Program at
Langley Research Center, is a study of the potential effects of the
operation of a projected future fleet of high speed civil transport aircraft
(HSCTs). The Subsonic Assessment program (SASS) is a study of the effects of
the present subsonic aircraft fleet and of projected future subsonic fleets,
and is sponsored by the Advanced Subsonics Technology Program (AST) at
Langley Research Center. Objective Develop scientific basis for assessment
of atmospheric impact of subsonic and supersonic aviation, particularly
commercial aircraft cruise emissions.
Chemtrails
or Contrails: Conspiracy or Simple Science?
Contrails
over Bering Sea
Sea
WiFS Project, NASA/Goddard Space Flight Center, and
ORBIMAGE Satellite: OrbView-2 Sensor: SeaWiFS
The
conspiracy theory is that government officials are conducting
experiments in atmospheric science, and some of them involve a highly
classified military project which involves protecting us from some as
yet unknown threat. The side effects of people getting sick is part of
the price we pay for defense is what the "conspiracy obsessed
people" think.
Contrails
Over Lake Superior
SeaWiFS
Project, NASA/Goddard Space Flight Center, and ORBIMAGE Satellite:
OrbView-2 Sensor: SeaWiFS
People
worldwide are reporting what they describe to be unusual activity in the
sky, including jets leaving trails at low altitudes, spray lines
creating X's, S's and parallel lines, lines that slowly spread to create
a canopy of haze, and reports of unusual smells, tastes, and even
illness related to the trails.
This conspiracy theory has been sweeping
the Internet and radio talk shows has set parts of the federal
government on edge. The US Government has received thousands of phone
calls, e-mails and letters in recent years from people demanding to know
what's being sprayed and why.
The
Environmental Protection Agency, NASA, the Federal Aviation
Administration and the National Oceanic and Atmospheric Administration published a fact sheet explaining the
science of contrail formation.
http://www.epa.gov/otaq/regs/nonroad/aviation/contrails.pdf
A
few months earlier, the Air Force had put out its own fact sheet, which
tries to refute its opponents' arguments point by point. "If you
try to pin these people down and refute things, it's, 'Well, you're just
part of the conspiracy,' " says atmospheric scientist Patrick
Minnis of NASA's Langley Research Center in Hampton, Va. "Logic is
not exactly a real selling point for most of them."
U.S.
Air Force Report
The
"Chemtrail" Hoax
A
hoax that has been around since 1996 accuses the Air Force of being
involved in spraying the US population with mysterious substances and
show various Air Force aircraft "releasing sprays" or
generating unusual contrail patterns. Several authors cite an Air
University research paper titled "Weather as a Force Multiplier:
Owning the Weather in 2025" (http://www.au.af.mil/au/database/research/ay1996/acsc/96-025ag.htm)
that suggests the Air Force is conducting weather modification
experiments. The purpose of that paper was part of a thesis to outline a
strategy for the use of a future weather modification system to achieve
military objectives and it does not reflect current military policy,
practice, or capability.
The
Air Force's policy is to observe and forecast the weather. The Air Force
is focused on observing and forecasting the weather so the information
can be used to support military operations. The Air Force is not
conducting any weather modification experiments or programs and has no
plans to do so in the future.
The
"Chemtrail" hoax has been investigated and refuted by many
established and accredited universities, scientific organizations, and
major media publications.
Claims
and Facts
Claim:
Long-lasting contrails are something new and they have abnormal
characteristics.
Fact:
Contrails can remain visible for very long periods of time with the
lifetime a function of the temperature, humidity, winds, and aircraft
exhaust characteristics. Contrails can form many shapes as they are
dispersed by horizontal and vertical wind shear. Sunlight refracted or
reflected from contrails can produce vibrant and eye-catching colors and
patterns. Observation and scientific analysis of contrails and their
duration date back to at least 1953.
Claim:
Grid patterns of contrails in the sky are evidence of a systematic
spraying operation.
Fact:
The National Airspace System of the United States is orientated in an
east-west and north-south grid with aircraft flying at designated 2000
foot increments of elevation. Contrails formed by aircraft may appear to
form a grid as the winds disperse the contrails. More contrails are seen
in recent years due to the growth in the civil aviation market. The FAA
is responsible for the NAS and Air Force aircraft operate under the same
rules and procedures as civilian aircraft when using the NAS.
Claim:
There are reported outbreaks of illness after the appearance of "Chemtrails"
Fact:
There is no such thing as a "Chemtrail". Contrails are safe
and are a natural phenomenon. They pose no health hazard of any kind. If
there are massive outbreaks of illnesses, your local health department
should be able to tell you if it is an abnormal event. Local health
departments generally network together when they start seeing problems.
If there is a problem, the CDC will get involved.
Claim:
Samples taken have shown the presence of the "DOD patented"
bacteria pseudomonas fluorescens.
Fact:
The bacteria claimed to be DOD developed and patented is actually a
common, naturally occurring bacteria. The U.S. Patent Office (www.uspto.gov)
lists 181 patents involving pseudomonas fluorescens, none of which are
held by DOD.
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