Weather modification

The deliberate weather modification is used to generate the desired local weather conditions or avoiding harmful weather or weather influences on people or valuable equipment. To influences that manifest themselves more or less unintentionally as a product of human activity to natural law, see under climate change.

• 3.1 UN conventions
• 3.2 USA
• 3.3 ENMOD Convention

Methods for influencing the small-scale weather

Through in-depth knowledge of the laws of nature one can today to influence certain meteorological processes on a small scale to mitigate mainly to weather extremes:

• Add fruit and wine growing areas can prevent damage frosts, by creating strong smoke, which reduce the appearance of the earth and the lower layers of the atmosphere, or by frost protection irrigation, in which the released heat of crystallization protects the flowers.
• Also water surfaces ( lakes, ponds and ditches) affect some frost protection for surrounding areas. The effect is particularly noticeable in fruit-growing areas such as the old country during flowering.
• In steppe areas can establish so-called protective forest strips, reduce the drying out by the wind and thus the evaporation by planting suitable tree species. Thus, the soil water balance is improved, the dew formation is favored and the danger of drifting snow is reduced.
• Since the early 1950s it is possible to let clouds rain down artificially. By introducing artificial condensation nuclei ( " dry ice ", silver or lead iodide ) into existing clouds, for example by means of an explosive charge or controlled by an appropriately equipped aircraft (hail flyer ) an enlargement of the drop is reached, leading to the onset of rain. This process is referred to as " seeding " the clouds. By vaccinating can resolve long-running high clouds or fog near the airport, so that a country lane arise and normal operation can be resumed. Small-scale storm - fighting is to bring through the inoculation of thunderclouds these premature raining before they reach valuable cultivated land, therefore to prevent hail damage.
• Damage caused by lightning strikes can be reduced by setting up of lightning rods or attaching lightning rod systems on buildings. The high voltages between thundercloud and ground discharge namely preferably via the highly conductive lightning rod.

Methods for long-range influence of weather and climate

Large-scale weather and climate conditions

The large-scale influence of the weather or even the climate is still in the experimental stage. Various research groups have developed the first theoretical and practical approaches to manipulation, that are tried again and again.

It was even discussed to seal off the Bering Strait in the Arctic Ocean and at the same time to pump warm water from the Pacific Ocean in the Arktikbecken to make the Arctic climate milder. In this case, however, the ice would melt and the sea level would be raised, which would be an undesirable effect.

In the vicinity of airports and air route intersections may occur weatherproof effective frequent formation of cirrus clouds from contrails. The deliberate emphasis of this effect by chemical means was proposed in a U.S. patent as a method against global warming. Recent research, which are very controversial, however, predict an increased warming through more contrail cirrus clouds.

Experiments on a larger scale to be made in the People's Republic of China. It maintains a state " weather modification office," which provided at the Olympic Games in Beijing in 2008, or to celebrate the 60th anniversary of the founding of the People's Republic on 1 October 2009 for fair weather. For this purpose, aircraft chemicals sprayed, let the rain clouds rain down away from the capital. As a countermeasure against a prolonged drought should be produced, but the manipulations triggered an unwanted snowstorm, which caused problems in the capital in November 2009 rain. Also in Venezuela and Russia such measures for the production of rainfall are being considered.

The impact of Hurricane

A research group headed by Ross N. Hoffman of the U.S. firm Atmospheric and Environmental Research ( AER), Lexington (Massachusetts ) has studied on the example of the hurricane, how far a big storm can be manipulated, and whether it is possible thus avoiding harmful or destructive effects. For this purpose, first had the course of a hurricane can be accurately predicted absolute, which was particularly difficult because the Earth's atmosphere reacts in its capacity as a chaotic system is extremely sensitive to the slightest disturbance. Make predictions of the course of a hurricane is. Difficult than in the boundary layer, because there can no longer speak of a closed system, since heat is exchanged with the sea surface The computer simulations are therefore approximations based on predictions.

The research group presented the following theoretical possibilities for changing certain parameters:

• Increase in temperature in the atmosphere, so that the condensation of water vapor and thus the cloud formation can be prevented by microwave radiation from solar power stations in orbit, which is not feasible at this time.
• Reducing the evaporation of sea surface by the application of biodegradable oil films, which would also complicate the formation of clouds.
• Specific adaptation of routes to the formation of contrails (see above).
• Use of irrigation in order to change the rate of evaporation localized.

The researchers warn of the danger that targeted weather manipulation can be used as a weapon, so to inflict harm on others. It therefore had to be outweighed risks and benefits. ( ENMOD Convention)

Global Climate

The vast majority of researchers is convinced that the introduction of greenhouse gases such as carbon dioxide and certain hydrocarbons in the atmosphere affects the climate. The actual effects are still controversial, because the atmosphere and the climate are a chaotic system, but it is widely agreed that it is thereby also to regional changes in the weather - will come - quite in opposite directions. In addition to global warming, the result could lead to cooling in northern Europe does.

Decrees and prohibitions

UN conventions

The Environmental Modification Convention of 1977 prohibits any form of weather modification for military purposes.

USA

The Senate and the House of Representatives were submitted in 2005 proposed legislation to authorize experimental weather modification, but not approved.

ENMOD Convention

The ENMOD Convention prohibits signatory countries, harming the environment in a conflict deliberately or use such a damage to the environment as a military advantage or weapon. The ENMOD Convention was ratified by May 2007 by 73 countries.