Ten things you probably didn't know about

Artificial Clouds ...or hadn't thought about

Dave Dahl | ©2014

t is easy to forget that everything we burn creates

moisture. Like the steam you can sometimes see from

your tailpipe, burning any kind of fuel creates water vapor.

Jet aircraft produce a gallon of water for every gallon of jet

fuel they use, because H2O is one of the two chemical byproducts

resulting from the combustion of hydrocarbons... that is, burning

jet fuel. (The other, of course, is CO2.) So? Jets make vapor trails.

We knew that.

So it makes us wonder (those of us who have noticed) about the

causes and effects of thick contrails that can form persistent

clouds... clouds that can change the weather and sometimes

cover the whole sky. Can this really just be the result of more air

travel and bigger, more powerful jets? Of course, that part is

pretty clear as well. But could something else be different too? Is

the fuel different? Not really. Are they spraying sulfur dioxide for

solar radiation management? No, not yet. Experiments, no doubt,

but it wouldn't look like this. And while there are plenty of

climatologists that seem eager to try SRM─ and we have the ability

to attempt "geo-engineering" using this approach─ it probably

wouldn't explain the constant increase in artificial cloud

production we have been seeing since the 1970s.

But there definitely are new factors affecting cloud-aerosol

interaction since the original understanding of contrails and their

definition were first introduced at the beginning of the twentieth

century... factors we should consider.

And since NASA tells us that "even small changes" in the

abundance clouds could affect on the climate more than CO2,

understanding clouds and what else is different about our

atmosphere could be an important part of understanding climate

change...

I"Even small changes in the abundance or

location of clouds could change the climate

more than the anticipated changes caused

by greenhouse gases."

─ NASA

Jet aircraft produce about 10 trillion cubic feet of water

vapor annually. That's a rough calculation based strictly

on consuming 60 billion gallons of jet fuel each year. At the

sub-zero temperatures where contrails form, steam from

the exhaust freezes and expands to about a hundred times its

sea-level volume in the low air pressure of the stratosphere. 60

billion gallons of fuel = 60 billion gallons of water = approximately

10 trillion cubic feet of steam producing ice crystal clouds.

Weather modification programs affect contrail cloud

formation. Weather modification means cloud seeding

with silver iodide (AgI)─ hygroscopic metallic aerosols that

provide a dense field of cloud condensation nuclei to

thicken clouds and induce precipitation. These

condensation nuclei are the basis of cloud development

and, when mixed with moisture, silver iodide promotes cloud

formation by providing CCNs that jet exhaust moisture can bond

with. The invisible cloud-seeding chemicals are dispersed in the

atmosphere before incoming moisture fronts, enhancing contrails

from jet air traffic and often spawning cloud cover prior to the

storm's arrival.

1

2

As aircraft ascend through areas of high relative humidity (ice crystal saturation) or dense cloud condensation nuclei, exhaust moisture

bonds with the nuclei to form ice crystals.

Depending on where the sun is, contrails can appear bright white, dark gray, or colorful.

Weather modification programs burn silver iodide flares

to induce precipitation. Weather modification companies

use fleets of jets and high-altitude propeller planes that have

flares fixed to the wings of the aircraft. When the flares burn,

they release silver iodide, a salt-based chemical (potassium

iodide and silver nitrate), which provides abundant cloud

condensation nuclei to spawn and thicken clouds. Cloud seeders

ignite as many flares as possible before incoming storms in order

to maximize precipitation. There are other less common

applications for cloud seeding, such as breaking up hailstorms

with surfactants in order to reduce damage, but precipitation

enhancement is the primary reason for weather modification.

Local governments hire the cloud seeding companies.

In the United States, county governments hire weather

modification companies to seed clouds. The programs are

designed to enhance precipitation and increase water

supplies. These projects are typically paid for by consumers

through a Public Purpose Program surcharge on their utility bills.

Local governments see cloud seeding as a good value for

obtaining additional water; other sources are more costly, if any

are even available.

3

4

Texas Weather Modification Association

Countries worldwide use cloud seeding regularly. Most

western states in the US conduct ongoing cloud seeding

programs for precipitation enhancement. As global water

supplies diminish, few alternatives exist to provide enough

water for growing populations and increasing agricultural

needs. Almost any country you can name uses cloud seeding

to increase rainfall and snowpack that keeps rivers flowing

through the summer, including Australia, Europe, South

America, the Middle East and Asia. China cloud seeds in over

2,000 counties. Dry states in the US like California have seeded

the atmosphere with silver iodide every year since the 1960s.

Other states have caught on and, as the worldwide water shortage

begins to affect more and more cities, the weather modification

industry has expanded drastically over the past few decades. The

massive amounts of cloud condensation nuclei result in thicker,

more persistent contrails, more artificial clouds and hazy skies

over Earth's northern hemisphere. (Cloud seeding with AgI began

in the 1960s; "climate variation" concerns started in the 1970s.)

5

States with ongoing cloud seeding programs:

• California

• Colorado

• Georgia

• Idaho

• Illinois

• Iowa

• Kansas

• Montana

• Nevada

• New Mexico

• North Dakota

• Oklahoma

• Oregon

• South Dakota

• Texas

Notable court cases have taken place in:

• New York

• Oklahoma

• Washington

• Nebraska

• Pennsylvania

• Montana

• South Dakota

• North Dakota

• Texas

• California

• Utah

• Washington

• Wyoming

Artificial clouds cool AND warm the Earth. Clouds

can drastically affect the weather: In the daytime they

block the sun, creating shade and reflecting some

solar radiation back into space. But at night, clouds

have a blanketing effect that keeps warm air trapped.

The coldest nights are usually cloudless ones since

the heat can escape from the Earth. Clouds also

absorb and re-emit heat, so cloud cover makes it even

warmer at night. Warmer air also means higher

pressure, and high pressures can also help repel

some storms, preventing rain.

6

NASA

Artificial clouds can amplify storms. When a moisture front

presents itself, cloud seeding companies go into action, dispersing

silver iodide in front of the incoming storm... specifically, over

areas of land where precipitation is desired. These hygroscopic

aerosols provide a field of CCNs for jet exhaust moisture to bond

with and, combined with the higher ice crystal saturation that

comes from moisture preceding the storm, aircraft can spawn

thick clouds before the storm clouds arrive. This provides a shady

area in the path of the incoming storm, creating a low-pressure

"downhill run" for the storm. In fact, this can allow some

precipitation to make landfall that would otherwise be repelled by

higher pressure.

.

Artificial clouds can amplify storms. When a moisture

front presents itself, cloud seeding companies go into

action, dispersing silver iodide in front of the incoming

storm... specifically, over areas of land where precipitation

is desired. These hygroscopic aerosols provide a field of

CCNs for jet exhaust moisture to bond with and, combined

with the higher ice crystal saturation that comes from moisture

preceding the storm, aircraft can spawn thick clouds before the

storm clouds arrive. This creates a shady area in the path of the

incoming front, providing a low-pressure "downhill run" for the

storm. In fact, this can allow some precipitation to arrive that

would otherwise be repelled by higher pressure.

7

NASA

Artificial clouds tend to move eastward. In the United

States, weather typically moves across the country from

left to right with the jet stream. This means storms we

intensify in the western states tend to flow toward the eastern

states. Through precipitation enhancement programs, we

thicken and accelerate storms, which continue eastward

with the winds... along with the extra cloud condensation nuclei

we introduce into the atmosphere to enhance precipitation. How

often do the western states seed the clouds? Every time there's

potential for rain or snow. We need the water. But who is aware of

the downstream consequences?

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CLOUD

SEEDING

POWERSTORMS

FLOODING

Artificial clouds destroy the ozone layer. Recently

scientists found that stratospheric water vapor destroys

ozone. This is troubling because in addition to adding

CO2 directly into the upper atmosphere, jet aircraft inject

their water vapor into the lower stratosphere where the

ozone layer helps protect the Earth from solar radiation. In

addition, our heavy cloud seeding practices using salt-based

material may temporarily inhibit evaporation in some areas by

increasing the surface salinity of water bodies that provide the

humidity for cloud formation.

Cloud seeding flares contain toxic metallic

aerosols. Just like road flares, which also contain toxic

metals, cloud seeding flares have to burn in wet, high-

wind conditions. Besides silver nitrate and potassium

iodide─ an inorganic salt─ cloud seeding flares contain incendiary

chemicals and metals that are toxic to living things, including

aluminum, strontium and magnesium.

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In the western United States, artificial clouds spawned by aircraft are more common than natural clouds.

1

The Effects of Artificial Clouds on Climate

An Examination of Jet Aircraft and Cloud-Aerosol Interaction

Dave Dahl | May 2014

ABSTRACT

Since the 1960s, high-altitude weather

modification programs have increased

worldwide. The effects of A) commercial

aircraft injecting trillions of cubic feet of

water vapor into the sky annually and B)

the precipitation enhancement activities

of weather modification aircraft combine

to produce significant cloud cover over

the Earth, affecting temperatures and

weather conditions more than CO2 or

other greenhouse gases. We are

continually modifying the weather via

aircraft; therefore, we are also modifying

the climate via aircraft.

1. INDICATIONS THAT EARTH'S CLIMATE IS CHANGING

We believe Earth's climate is changing

because we can observe the weather

changing. Higher temperatures, melting

glaciers, worsening storms... all the signs

of climate change, including rising sea

levels from melting ice, have to do with

weather pattern observations, in particular

warming trends. 1

(End notes page 10)

PREMISE 1:

WE KNOW THE CLIMATE IS CHANGING BECAUSE OF OBSERVED CHANGES

IN WEATHER PATTERNS.

2. "CLIMATE" VERSUS "WEATHER"

"Weather" is what we are experiencing

today; "climate" is what we experience

year after year. In other words, climate =

weather over time. If we modify the

weather continuously, we would modify

the climate.

PREMISE 2:

CHANGING THE CLIMATE MEANS CHANGING THE WEATHER; CHANGING

THE WEATHER OFTEN = CHANGING THE CLIMATE.

2

3. EVIDENCE THAT CO2 CAUSES CLIMATE/WEATHER CHANGES

Strong evidence suggests that CO2

emissions are contributing to a global

warming trend. Correlative data indicates

a connection; however, it does not equal

causation. Other "rising correlations"

exist which do not affect the climate, and

high CO2 levels in ancient ice

corresponding with temperatures2 does

not constitute proof that CO2 is currently

causing warming. Experimental data is

from small-scale testing on micro-models

which are only loosely analogous to the

entire Earth; in fact, we are far from being

able to accurately model the whole planet

and all its processes to predict weather

and climate events. But we know that

each gallon of fuel we burn results in

nearly 20 pounds of carbon dioxide added

to the air, and as far we can tell, CO2

stays trapped in the upper atmosphere

indefinitely.4 However, connecting all

this evidence to specific weather patterns

or predicting weather events is complex

and involves many variables.

PREMISE 3:

WE DO NOT KNOW PRECISELY HOW MUCH CO2 AFFECTS TEMPERATURES

AND WEATHER EVENTS COMPARED TO OTHER FACTORS.

4. NASA: THE EFFECT OF CLOUDS ON CLIMATE

According to NASA, "Even small

changes in the abundance or location of

clouds could change the climate more

than the anticipated changes caused by

greenhouse gases, human-produced

aerosols, or other factors associated with

global change."5 Let's assume NASA is

correct; in fact, we can directly observe

that clouds block the sun in the daytime,

resulting in shade and lower ground

temperatures; at night, clouds provide

insulation that prevents heat from

radiating away from the Earth. Therefore,

"even small changes" in the amount of

cloud cover could significantly change the

Earth's climate and weather patterns.

PREMISE 4:

CHANGES IN CLOUD COVER AFFECT EARTH'S WEATHER AND CLIMATE.

5. WHY CLOUDS AFFECT WEATHER PATTERNS

Clouds provide a cooling effect in the

daytime because, of course, clouds block

sunlight. Adding more clouds would

increase the Earth's albedo (brightness)

and reduce insolation (the amount of solar

energy reaching the ground) by deflecting

the solar radiation back into space and

diffusing, filtering or scattering the

radiation spectrum that penetrates the

clouds.5 Clouds provide warming at

3

night, because they create an "igloo" or

blanketing effect; heat is prevented from

escaping into space, so the ground doesn't

cool down as much prior to getting re-

heated the next day. (Clear nights are

generally much colder than cloudy nights,

while sunny days are usually warmer than

cloudy days.)6 Clouds also create and

accelerate wind. In the daytime, clouds

create shade; the temperature drops in the

shaded area, and the air contracts and

descends. Warmer air from the

surrounding area rushes in to take up the

space left by the contracting air.7

Clouds may also prevent precipitation. At

night, cloud cover can re-emit the heat

absorbed during the daytime and prevent

heat from escaping. This creates warmer

nighttime temperatures, resulting in

higher pressure that can deflect some

storms away from that area.8

PREMISE 5:

CLOUDS AFFECT AIR TEMPERATURE, PRESSURE AND WIND.

6. ANTHROPOGENIC CLOUD PRODUCTION

Humans can and do produce clouds, far

more than almost anyone realizes,

including people within the scientific

community. We make clouds around the

Earth furiously.9 We know that

condensation trails from jet aircraft can

form persistent cloud cover, and alarmed

witnesses around the world have seen

aircraft contrails thicken, merge together,

and cover the entire sky. Humans are

constantly creating clouds through

aircraft.

.

High-altitude artificial clouds created by aircraft condensation trails

4

NASA satellite image of jets forming contrail clouds

NASA satellite image showing jet contrails forming cloud cover

5

PREMISE 6:

JET AIRCRAFT DIRECTLY AFFECT THE ABUNDANCE AND LOCATION OF

CLOUDS; HENCE, AIRCRAFT AFFECT WEATHER CONDITIONS.

Contrails forming clouds in California before storm clouds arrive

7. HOW MUCH DO AIRCRAFT ACTUALLY CONTRIBUTE TO CLOUDS?

Answer: Aircraft produce approximately

10 trillion cubic feet of water vapor per

year. This rough calculation is based

exclusively on global jet fuel

consumption of about 60 billion gallons

per year,10 and does not include the steam

produced from all the other carbon-based

fuel combustion. Jet fuel combines with

oxygen to burn and produce water and

carbon dioxide (2 C12H26 + 37 02,

producing 24 CO2 + 26 H2O).11 If we

consume 60 billion gallons of jet fuel

annually, we are introducing 60 billion

gallons (480 billion pounds) of WATER

into the atmosphere each year. 60 billion

gallons of H2O = ~10 trillion cubic feet of

water vapor (the frozen steam expands

~100x in the low-pressure upper

atmosphere where contrail clouds form).

PREMISE 7:

JET AIRCRAFT INJECT CO2 AND H20 INTO THE UPPER ATMOSPHERE,

CREATING TRILLIONS OF CUBIC FEET OF ADDITIONAL "CLOUD VAPOR"

ANNUALLY.

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8. CONDITIONS AFFECTING THE FORMATION OF ARTIFICIAL CLOUDS

On some days there are no visible contrail

clouds. Other factors being equal, this is

primarily because of relative humidity─

insufficient ice crystals for contrails to

bond with in order to accumulate and

persist.12 But we must remember that the

"humidity" in the lower stratosphere is

not actually "liquid" moisture anymore;

nor is the water vapor a "gas." When they

bond at sub-freezing temperatures, H2O

molecules form solid crystalline

structures, so after the super-heated

exhaust vapor is blasted from the jet

engine's manifold at over two thousand

degrees, it instantly freezes and bonds

into tiny ice crystals... micro-snowflakes.

High relative humidity means greater

density of these tiny ice crystals, which

also act as cloud condensation nuclei

(CCNs), facilitating persistent contrail

clouds by providing the cloud-forming

nuclei for exhaust moisture to bond with.

PREMISE 8:

JET EXHAUST + SUFFICIENT MOISTURE (RH) / SUFFICIENT CCN = CLOUDS.

9. WEATHER MODIFICATION ACTIVITY AND CLOUD FORMATION

"Weather modification" consists

primarily of cloud seeding, primarily

using aircraft, primarily to enhance

precipitation. There are minor exceptions.

Since the 1960s, high-altitude weather

modification programs have increased

worldwide.13 We know that sufficient

cloud condensation nuclei and "moisture"

(ice crystal saturation/CCN concentration)

are required for jets to form persistent

clouds. Ongoing weather modification

programs add massive amounts of cloud

condensation nuclei to the upper

atmosphere before every rain or snow

storm (18,000 to 22,000 feet and higher14)

in order to induce greater precipitation.

PREMISE 9:

WEATHER MODIFICATION ACTIVITIES ADD SIGNIFICANT CCNs TO THE

ATMOSPHERE, FACILITATING CLOUD FORMATION.

10. INCREASES IN WEATHER MODIFICATION ACTIVITY

Weather modification via high-altitude

cloud seeding is conducted regularly in

almost every western state in the US. At

least 68 counties engage in documented,

ongoing "precipitation enhancement"

programs14 covering millions of square

miles. Nations that need more water for

growing populations and agriculture,

which is most of them, use cloud seeding

programs to try to increase water

supplies.14 China seeds clouds in over two

thousand counties.15 The result is

increased atmospheric cloud condensation

nuclei over every continent.

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PREMISE 10:

THE WEATHER MODIFICATION INDUSTRY HAS EXPANDED SINCE THE 1960S

TO BECOME GLOBAL AND PROLIFIC, ADDING MORE AND MORE CLOUD-

FACILITATING CHEMICALS TO THE ATMOSPHERE.

11. EXTRAPOLATIONS

Based on the ten preceding premises, we can see that humans are continually modifying

the weather via aircraft; therefore, we are also modifying the climate via aircraft.

A. Jet aircraft add billions of gallons of water to the upper atmosphere (which equals

trillions of cubic feet of frozen water vapor) and produce clouds to varying degrees,

including widespread white haze and often thick cloud cover.

B. The AgI-based (silver iodide) weather modification activities and industry that

started in the 1960s have continued to grow and have spread globally, adding

massive amounts of cloud-facilitating CCNs into the atmosphere around the world.

C. The combination of jet plane transportation adding water vapor plus weather

modification aircraft adding cloud condensation nuclei equals added cloud cover.

Aircraft are therefore directly affecting the weather by spawning clouds as they

ascend to cruising altitude16. (Most weather modification events, air traffic and

artificial cloud production take place in the northern hemisphere, where the greatest

"climate change" is being observed.)

D. Clouds cool the Earth in the daytime but prevent heat from escaping at night. The

net result of additional cloud cover is probably higher average temperatures, since

the ground doesn't cool down as much at night before being re-heated by the

daytime sun.

E. Increasing clouds = increasing wind = increasing storms. When all the western

states conduct cloud-seeding events to increase water supplies, the additional cloud

condensation nuclei continue to travel eastward with the winds. As the CCN

aerosols gather more moisture and form clouds, the additional cloud cover from

aircraft flying in front of the storm lowers the air pressure, accelerating winds.

F. Burning jet fuel produces twice as much CO2 as water vapor (almost 20lbs vs. 8lbs

per gallon, respectively) and doesn't come back down to Earth as water does.

8

But water is extremely heat-conductive and traps far more heat energy than CO2... and

water crystallizes and forms clouds that immediately affect temperatures, pressures and

winds.

G. Water vapor introduced by jets into the lower stratosphere also destroys the ozone

layer, which could affect the levels of solar radiation reaching the ground. 17

H. Cloud-seeding flares use toxic chemicals, including silver iodide, aluminum,

strontium and magnesium. These chemicals and have been accumulating in our soil,

water and lungs for decades. 18

I. Cloud seeding uses salt-based chemicals that may affect water surface salinity,

temporarily inhibiting evaporation in some areas. 19

12. CLOUD SEEDING AND THE LAW

Cloud seeding is not illegal in the United States (or any of the countries examined for

this report). Court cases about cloud seeding have taken place in many states13,

including noteworthy cases in

• New York

• Oklahoma

• Washington

• Nebraska

• Pennsylvania

• Montana

• South Dakota

• North Dakota

• Texas

• California

13. COMMERCIAL WEATHER MODIFICATION COMPANIES

Weather modification programs in the United States are usually conducted at the

county level through utility companies that hire weather modification fleets

(typically Bombardiers and Hawker Jets and high-altitude propeller planes), which

are paid for by consumers through the Public Purpose Programs surcharge on the

utility bill. Weather modification companies in the US include:

• North American Weather Consultants [ http://www.nawcinc.com/ ]

• Weather Modification, Inc [http://www.weathermodification.com/ ]

• Western Weather Consultants [ http://westernweather.net/wordpress/ ]

• Meteo Systems [ http://www.meteo-systems.com/ ]

• Atmospherics, Inc [ https://www.facebook.com/AtmosphericsInc ]

• WET International [ http://www.wet-intl.com/ ]

• Ice Crystal Engineering [http://www.iceflares.com ]

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14. STATES CURRENTLY CONDUCTING CLOUD SEEDING

US States conducting extended weather modification activities or ongoing

precipitation enhancement programs using aircraft with cloud seeding flares:

• North Dakota [ http://www.startribune.com/local/175173981.html?refer=y ]

• California [ http://www.countyofsb.org/pwd/pwwater.aspx?id=3740 ]

• Colorado [ http://www.nawcinc.com/NAWC%20Operational%20Programs.pdf ]

• Georgia [ http://www.nawcinc.com/NAWC%20Operational%20Programs.pdf ]

• Idaho [ http://earthfix.opb.org/water/article/idaho-power-looks-to-cloud-seeding-to-enhance-wint/ ]

• Illinois [ http://www.weathermodification.com/projects.php ]

• Iowa [http://www.nawcinc.com/NAWC%20Operational%20Programs.pdf ]

• Kansas [http://www.bibliotecapleyades.net/ciencia/secret_projects2/project339.htm ]

• Montana [http://www.nawcinc.com/NAWC%20Operational%20Programs.pdf ]

• Nevada [http://www.lasvegassun.com/news/2009/aug/31/budget-well-dry/ ]

• New Mexico [ http://www.weathermodification.com/projects.php ]

• Oklahoma [http://www.weathermodification.com/projects.php ]

• Oregon [ http://www.nawcinc.com/NAWC%20Operational%20Programs.pdf ]

• South Dakota [ http://www.nawcinc.com/NAWC%20Operational%20Programs.pdf ]

• Texas [ http://www.tdlr.state.tx.us/weather/weatherfaq.htm ]

• Utah [ http://www.water.utah.gov/cloudseeding/currentprojects/ ]

• Washington [ http://www.nawcinc.com/NAWC%20Operational%20Programs.pdf ]

• Wyoming [http://www.vcstar.com/news/2013/jan/04/wyo-cloud-seed-project-proceeds-despite-drought/ ]

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END NOTES & REFERENCES

1. IPCC Says Climate Change is Here, World Needs to Adapt

http://www.climatecentral.org/news/climate-changes-impacts-are-here-will-

worsen-without-adaptation-ipcc-says-17240?gclid=CKHJy-

eJtL4CFUiEfgodaDAAGw

2. 800,000-year Ice-Core Records of Atmospheric Carbon Dioxide

http://cdiac.ornl.gov/trends/co2/ice_core_co2.html

3. Glory and Global Warming Experiment

http://glory.gsfc.nasa.gov/globalwarmingexperiment.html

4. Wonderfest 2010: Dare We Try to Engineer Earth's Climate?

http://fora.tv/2010/11/07/Wonderfest_2010_Dare_We_Try_to_Engineer_Eart

hs_Climate

5. NASA: The Importance of Understanding Clouds

http://www.nasa.gov/pdf/135641main_clouds_trifold21.pdf

6. Rosalind Peterson, Agriculture Defense Coalition

http://www.agriculturedefensecoalition.org

7. What causes wind?

http://www.weatherquestions.com/What_causes_wind.htm

8. The 7 Types of Weather in a High Pressure System

http://weather.about.com/od/pressureandtemperature/a/high_pressure.htm

9. NASA: Clouds Caused By Aircraft Exhaust May Warm the U.S. Climate

http://www.nasa.gov/home/hqnews/2004/apr/HQ_04140_clouds_climate.html

10. World Jet Fuel Consumption by Year

http://www.indexmundi.com/energy.aspx?product=jet-fuel

11. Combustion and Energy Release

http://telstar.ote.cmu.edu/environ/m3/s3/09fossil.shtml

11

12. NASA Contrail Identification Chart and Formation Guide

http://science-edu.larc.nasa.gov/contrail-

edu/pdf/resources/Contrail_ID_Chart_English_2013_v18_copy.pdf

13. Expansion of Weather Modification Programs

See page 9 above. Some relevant court cases about cloud seeding:

http://www.rbs2.com/weather.pdf

14. Precipitation Enhancement Primer

http://www.waterplan.water.ca.gov/docs/cwpu2009/0310final/v2c10_precipe

nhance_cwp2009.pdf

15. Cloud Seeding in China

http://english.caixin.com/2012-08-13/100423557.html?p0

16. Aircraft contrails have a beginning and end. The plane usually has no

visible contrail until it reaches the around 20,000 feet (common cloud-seeding

altitude). Depending on the ice crystal/CCN saturation, this is the zone where

contrails become visible, while the engines are at full throttle. Once the jet

reaches cruising altitude, it uses less fuel compared to when it's climbing, and

there is not enough moisture or CCNs to create the visible wake of ice

crystals. On descent, jet usually do not use enough fuel to create visible

contrails.

17. Reaction of Ozone and Climate to Increasing Stratospheric Water Vapor

http://www.giss.nasa.gov/research/briefs/shindell_05/

18. Cloud Seeding Flares

http://www.texasweathermodification.com/Flares.html

19. Sea Surface Salinity

http://science.nasa.gov/earth-science/oceanography/physical-ocean/salinity/

20. Why Water Vapor Destroys Ozone: UV Dosage Levels in Summer:

Increased Risk of Ozone Loss from Convectively Injected Water Vapor

http://www.sciencemag.org/content/337/6096/835.abstract

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.

Additional documentation, a video and more FAQs:

http://artificalclouds.com.

© Dave Dahl | dave@placemarkone.com