What does it mean to say that CO2 acts as a greenhouse gas?
The Earth’s atmosphere (made up of gases such as carbon dioxide and water vapour) is vital to life both in terms of its chemical composition (oxygen etc) and its ‘greenhouse’ role in maintaining habitable temperatures. The problem is that an increasing concentration of CO2 is enhancing the greenhouse effect so that even less heat energy can radiate into space from the Earth. The molecules of certain gases, including CO2, have a greater ability to absorb infrared radiation (the way the Earth transfers heat energy away from itself) and so the increasing CO2 concentration leads to increasing temperature.
