Artificial Weather Revealed by Post 9-11 Flight Groundings


Sayer Ji

In the three days that followed the 9/11 attacks, when all commercial flights above the continental US were suddenly suspended, a veil was lifted on the profound, though until that point unconfirmed, effects that aviation-associated artificial clouds are having on our planetary environment.

In the August 2002 edition of Nature, which is ranked the world’s most cited interdisciplinary journal, a report was published titled “Contrails reduce daily temperature range,” where scientists discuss how “a brief interval when the skies were clear of jets unmasked an effect on climate.” [Read Entire Article]

Three Days Without Contrails

The post-9/11 grounding of all commercial aircraft resulted in the sudden disappearance of condensation trails (contrails) from jet aircraft across the entire United States. According to the Nature study, the potential of contrails “…from jet aircraft to affect regional-scale surface temperatures has been debated for years…,” but it was not until the three-day grounding period that doubts concerning the existence of the phenomenon could be put to rest.

The Phenomenon: A 1.8 Degree Celsius Increase In Temperature in North America

The study found “…an anomalous increase in the average diurnal temperature range (that is, the difference between the daytime maximum and night-time minimum temperatures) for the period 11-14 September 2001.”


They arrived at their measurements by analyzing maximum and minimum temperature data from approximately 4,000 weather stations through the conterminous United States (excluding Hawaii and Alaska) for the period 1971-2000, and compared them to the three-day post-9/11 grounding period.

They found an increase in the diurnal temperature range (DTR) of approximately 1.1 degree Celsius over normal 1971-2000 values, and an increase of 1.8 degrees during the grounding period in contrast to the adjacent three-day periods analyzed when DTR values were near or below the mean.

This is a highly significant finding as “The increase in DTR is larger than any during the 11-14 September period for the previous 30 years…,” and since “…the 11-14 September increasing DTR was more than twice the national average for regions of the United States where contrail coverage has previously been reported to be most abundant (such as the Midwest, northeast and northwest regions).”

The study authors concluded

“Our findings indicate that the diurnal temperature range averaged across the United States was increased during the aircraft-grounded period, despite large variations in the amount of cloud associated with mobile weather systems. We argue that the absence of contrails was responsible for the difference between a period of above-normal but unremarkable DTR and the anomalous conditions that were recorded.”

Visible contrails


First, it is important to point out that the observed post-9/11 elevation in temperature is not one-dimensional. While clouds, including aviation-associated contrails may lower temperature by reflecting solar radiation off the planet in what is known as the “albedo” effect, they may also raise temperature by blanketing trapped heat preventing its nighttime radiative dissipation.

In fact, NASA’s Earth Observatory states that “NASA scientists have found that cirrus clouds, formed by contrails from aircraft engine exhaust, are capable of increasing average surface temperatures enough to account for a warming trend in the United States that occurred between 1975 and 1994.” The point, however, is that aviation-associated weather does profoundly affect temperature.

It is not necessary to believe in clandestine geoengineering programs, or malevolently dispensed chemical trails, in order to see the effect that modern day aviation is having – visibly — on our skies. Billions of pounds of jet fuel are burned each year, adding a vast amount (albeit mostly invisible) of chemical pollution to our environment.

While the mainstream still considers the persistent condensation trails formed by jets to be a harmless and ephemeral, a growing sector of the public is increasingly concerned about the “chemtrails” they are seeing blanketing the sky – a term, in fact, which generates millions of searches and web page results through Google, but is equated with “conspiracy theory” via automatic redirection on sites like Wikipedia or

Considering the results of the Nature article, there can be little doubt that these trails are having a profound effect on weather right now, and such a profound one, that within just three days of their cessation, a massive temperature anomaly occurred over a surface area of 9,326,410 sq km, the land mass of the United States.

Aircraft Contrails Southeast

If, and that’s a big IF, these temperature anomalies are a result of the absence of only jet exhaust, which we are told are “mostly water vapor,” the unintended cloud-producing effects of commercial aviation taken in its totality is already (unintentionally) a global form of geoengineering qua effects. Simply viewing a satellite image (example above) of commercial jet paths reveals how artificial clouds are now overtaking natural ones.

Since the 1990s, climatologists like Jane Long and Julio Friedman have advocated cooling the Earth through solar radiation management (SRM), which proposes injecting sulfur dioxide into the stratosphere. The sulfur clouds would block sunlight, imitating the cooling effects of volcanos. Advocates suggest that geo-engineering is not only cost-effective, but also the only realistic solution to the problem of global warming.

The idea that solar radiation management is our only option is based on two premises: First, SRM assumes that the climate is warming due to greenhouse gases building up, especially CO2. Second,that we cannot (will not) stop greenhouse gas emission, and the CO2 stays trapped in the upper atmosphere indefinitely.

However, other researchers are skeptical. A new documentary called Skywatcher: Contrails, Chemtrails and Artificial Clouds (public release 9-11-2012) offers a completely different perspective. The producer, Dave Dahl, asserts that we have missed the most important factor in climate change models: aircraft.

Climate modeling has started to include detailed studies of the effects of artificial clouds, which cool the ground during the daytime. Because of this, many people believe that covert SRM programs are already in full force. But clouds have a warming effect when they blanket the Earth at night, blocking the heat from escaping back into space. For this reason, clouds can cause overall warming, even though they bock sunlight during the daytime.

But according to Dahl, the immediate problem we face from climate change is global drying, not global warming, and our efforts to modify the weather with aircraft are toward the purpose of precipitation enhancement, not SRM. Furthermore, he asserts that artificial clouds created by aircraft are the cause of climate change, and our efforts to modify the weather are an aggravation, not a solution.

Governments worldwide are concerned about drought as the arid regions of the planet become even drier. But Dahl says today’s precipitation enhancement programs are worsening the problem of climate change, and even in the best-case scenarios, we will not be able to meet our growing water needs through weather modification.

“I think it’s this simple,” said Dahl in an interview. “Clouds affect the weather and the climate. We are making artificial clouds. So yes, we are changing the climate, and this movie shows that clouds made by jets are accelerating these changes far more than the buildup of CO2 or methane, and are in fact the primary factor in anthropogenic climate change.”

You can watch the preview trailer for Skywatcher at and view a free report on contrails, chemtrails and artificial clouds by David Dahl.


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