How can you change climate?

The climate can only be changed by years and years of massive pollution, which the earth is in a state of.

A:

There is substantial evidence that man can influence climate on a global and regional scale. So far the changes have been largely incidental due to the emissions of anthropogenic greenhouse gases which trap long wave radiation, thereby warming on a global level, and the emissions of sulphates which reflect solar radiation, thereby cooling on both a global and regional level. It is also likely that climate is changed through the emissions of black carbon particles, land use changes such as forestry and urban building, and the diversion and drainage of large volumes of water. Global climate change, both natural and anthropogenic can also potentially lead to significant changes on a regional level, although these are more difficult to prove or predict.

Whilst the most effective long term method of stabilising climate would be to reduce greenhouse gas emissions to natural levels, there is now substantial interest in controlling the climate to mitigate the warming caused from the release of anthropogenic (human produced) greenhouse gases. These geoengineering techniques fall into two main categories:

• carbon sequestration: These seek to capture and store greenhouse gases from the atmosphere. These include direct methods (e.g. carbon dioxide air capture) and indirect methods (e.g. ocean iron fertilisation).
• solar radiation management: These do not reduce greenhouse gas concentrations but reflect more of the suns radiation so they don't address problems such as ocean acidification, which are expected as a result of rising carbon dioxide levels. Examples of proposed solar radiation management techniques include the production of stratospheric sulphur aerosols, space mirrors, and cloud reflectivity enhancement.

(See geoengineering techniques in link for details)

Whilst, most of these geoengineering techniques are theoretically cheaper than reducing carbon over the short term, some might have unwarranted side effects, and therefore could be even more politically controversial. Some environmentalists also argue they are a serious distraction from the more important task of reducing carbon emissions, which would continue to rise to even more dangerous levels, and necessitate our continued dependence on geoengineering methods to stabilise climate.