The Greenhouse Effect

The Greenhouse Effect is the effect of heat-trapping ‘greenhouse gases’ (the most important being water vapour an carbon dioxide) which let through short-wave radiation from the sun but absorb long-wave radiation from the Earth and traps some of them to act like a blanket to keep the earth about 30 degrees warmer, keeping Earth habitable¹.

This natural greenhouse effect keeps the Earth balanced, unlike Mars and Venus.  Mars doesn’t’ have any greenhouse gases (GHGs)and is too cold to be habitable whilst Venus, on the other end of the extreme, has a thick blanket of greenhouse gases trapped in the atmosphere making it too hot to sustain life.  

Through human activities, primarily the burning of fossil fuels and long term deforestation, we have been increasing the concentration of greenhouse gases in the atmosphere and thickening our greenhouse blanket². 

The concern is that as emissions from human activities cause greenhouse gas concentrations to rise well above their natural levels and new greenhouse gases (such as CFCs and the CFC replacements) are added, the further global warming could threaten our own sustainability³.

² Grubb, M “The Climate Change Challenge 2005”, The Carbon Trust Website March 2005 
³ DEFRA, "Climate change and the greenhouse effect: Abriefing from the Hadley Centre", December 2005

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