Cirrus clouds are the usual fluffy and wispy clouds that we are so used to seeing everyday. They form at a height of about 5,500 metres and are about a quarter of all clouds formed at any one time on the planet. Due to Cirrus clouds having an ice crystal composition, they tend to calibrate the Earth's surface temperature. At first, the ice crystals in the clouds create a rather powerful albedo effect, where a portion of the sun's rays are reflected back into space. This prevents the sun from over heating the planet. Secondly the Cirrus clouds trap a portion of the outgoing infrared radiation, thus allowing the planet to stay warm at a constant temperature of 15 degrees centigrade. This is useful during night time, when the Sun isn't heating the surface.
The second process that is known as the greenhouse effect is extremely important at helping to maintain a stable habitable temperature on planet Earth. However due to the increase of greenhouse gases in the atmosphere, which in turn increases global warming, forced the surface temperature to increase from its normal 15 degrees centigrade. A slight increase in temperature, even by one degree may not seem as a large problem. However, what is not understood, is that even the slightest increase in temperature changes the albedo of the planet due to accelerated melting of ice caps, which in turn forces more solar radiation to be absorbed by heat sinks such as the ocean; and thus keep increasing the planet's temperature.
It is known from simple physics that any rise in temperature will cause objects to increase in volume. This same principle can be applied to water. Thus an increase in ocean temperature will equal in the sea level rise. This would be a catastrophy, as large areas of Earth could be submerged in water. This would wreck economic and political havoc and create millions of ecological refugees.
Another overlooked problem is that the melting ice caps dilute the ocean's salinity, thus slowing down and eventually shutting down the global conveyor belt, which distributes heat evenly across the globe. The consequence of this could be a devastating freeze or an ice age as it is commonly known. Therefore, it had been proposed by atmospheric scientists to dissipate Cirrus cloud cover across the planet. The ice crystal structure of the clouds, will increase the albedo and will allow more of the Sun's radiation to be reflected back into space. This will aid in cooling the planet and could act as a safety net, if alternative technology isn't found and more greenhouse gasses are continued to be pumped into the atmosphere. Cirrus clouds form when the heating of the surface by the sun causes warmer air and water vapour to rise. Once risen to its neutral buoyancy level the water vapour condenses into water droplets and ice crystals So by seeding the present clouds with special particles, would allow the present ice crystals to grow in size and become more abundant.
As effective as this may seem it is, however, not a solution to the global warming and greenhouse gases problems. It is only a mediator that would slow down the process. Also the increase in cirrus clouds would only feed and increase the greenhouse effect, due to the cloud's ability to trap infrared radiation on the planet's surface. In effect, there would be no need to seed Cirrus clouds, as the increasing temperatures will automatically increase them in numbers.
The extent of global warming depends largely on the size of the ice crystals within the Cirrus clouds. However, the albedo could only help refrigerate the planet to a certain extent, as there is a limited amount of ice on the planet; while greenhouse gasses can be pumped into the atmosphere indefinitely. This means that the seeding of Cirrus clouds will prove to be obsolete as a more permanent solution will need to be created that will deal with the core problem of global warming...greenhouse gases that come from the burning of fossil fuels.