In 2025, uninhabited aerospace vehicles (UAV) are routinely used for weather-modification operations.
David L Mitchell and William Finnegan
Desert Research Institute, Reno, NV 89512-1095, USA E-mail: firstname.lastname@example.org
Received 1 April 2009 Accepted for publication 12 August 2009 Published 30 October 2009 Online at stacks.iop.org/ERL/4/045102
Greenhouse gases and cirrus clouds regulate outgoing longwave radiation (OLR) and cirrus cloud coverage is predicted to be sensitive to the ice fall speed which depends on ice crystal size. The higher the cirrus, the greater their impact is on OLR. Thus by changing ice crystal size in the coldest cirrus, OLR and climate might be modified. Fortunately the coldest cirrus have the highest ice supersaturation due to the dominance of homogeneous freezing nucleation. Seeding such cirrus with very efficient heterogeneous ice nuclei should produce larger ice crystals due to vapor competition effects, thus increasing OLR and surface cooling. Preliminary estimates of this global net cloud forcing are more negative than −2.8 W m−2 and could neutralize the radiative forcing due to a CO2 doubling (3.7 W m−2). A potential delivery mechanism for the seeding material is already in place: the airline industry. Since seeding aerosol residence times in the troposphere are relatively short, the climate might return to its normal state within months after stopping the geoengineering experiment. The main known drawback to this approach is that it would not stop ocean acidification. It does not have many of the drawbacks that stratospheric injection of sulfur species has.
Geoengineering may be a means to create a time buffer against catastrophic climate change while long-term emissions reduction actions take effect. One approach is to disperse particulates at high altitude to reduce the effective solar flux entering the atmosphere. Sulfur compounds have been proposed, similar to the compounds emitted during volcanic eruptions that have been found to cool surface temperatures. As shown in Figure 1, the reduction in top-of-atmosphere solar flux is dependent on the quantity of sulfur dispersed per year. Other particulates may also be suitable. This study investigates means of transporting quantities geoengineering payload to altitude and releasing it at specified release rates. A variety of systems including airplanes, airships, rockets, guns, and suspended pipes are examined with a goal of lifting 1 million tonnes to alti- tude per year; we also evaluate 3 and 5 MT/year for a few delivery systems.
Going under a variety of names – atmospheric geoengineering, weather modification, solar radiation management, chemical buffering, cloud seeding, weather force multiplication – toxic aerial spraying is popularly known as chemtrails. However, this is merely one technique employed to modify weather. The practice of environmental modification is vast and well funded.real-agenda.com... real-agenda.com...
1. Add small reflecting particles in the stratosphere.
2. Add more clouds in the lower part of the atmosphere.
3. Place various kinds of reflecting objects or diffraction gratings in space either near the earth or at a stable location between the earth and the sun.
4. Change large portions of the planet's land cover from things that are dark and absorbing, such as trees, to things that are light and reflecting, such as open snow-cover or grasses.
1. Stratospheric aerosols
Adding more of the right kind of fine particles to the stratosphere can increase the amount of sunlight that is reflected back into space. This is not hard to do, nor all that expensive. David Keith has suggested that it should be possible to create microscopic reflecting composite particles that would be self- orienting and self-levitating, and thus might not have to be replaced very frequently. Sources: NASA; Boeing; www.carlstumpf.com A single nation could do these within it's national boundaries
2. Add more clouds
John Latham of the National Center for Atmospheric Research has proposed that salt from seawater could be effectively used as cloud condensation nuclei.
Stephen Salter of the University of Edinburgh has designed an "albedo spray vessel" which would put the Latham theory into practice.
3. Reflectors or diffraction gratings in space
4. Change land cover
For example, when the boreal forests were removed in the NCAR coupled ocean- atmosphere climate model, air temperature fell 12°C at 60°N in April and were still as much as 5°C colder in July.
The cost of geoengineering
As noted in the briefing paper: A National Research Council 1992 report estimated the undiscounted annual costs for a 40-year project to be $100 billion.
Teller, Wood and Hyde have suggested that well designed systems might reduce this cost to as little as a few hundred million dollars per year.
If we take cost to be between $100 million and $100 billion per year