Geo-engineering can be defined as the "deliberate modification of Earth's environment on a large scale "to suit human needs and promote habitability."

Given that climate change is the driving force behind geo-engineering a more appropriate definition might read: "Intentional, large-scale manipulation of the environment by humans to bring about environmental change, particularly to counteract the undesired side effects of other human activities such as global warming."

The notion of a technological fix for global warming is not a new one.
In the 1940s, Bernard Vonnegut, a well-respected meteorologist, found that silver iodide smoke could cause clouds to give up their rain.

His discovery kick-started serious government efforts to manipulate the environment. Until then, cloud-seeding had been the preserve of crackpots and con artists, but by 1951, 10% of the US was under clouds that had been commercially seeded.

Global warming is accelerating research into new geo-engineering technologies. Since 1993, there have been at least ten documented government and/or private experiments to “seed” sections of the ocean’s surface to demonstrate the feasibility of iron fertilization for sequestering carbon and countering global warming.