by James Hills

Created on: November 06, 2009

There are various aspects of climate change, very specifically the ones that are economically driven, that are well covered by the media such as fossil fuels and deforestation, but there is one factor which is absolutely critical to the world's energy balance which receives barely any coverage, and that is albedo.

Albedo is the term used to signify the amount of solar energy which is reflected by the earth's surface, with values being between 0 (absolute black) and 1 (absolute white) to signify the ratio of light absorbed/reflected.

The higher this value, i.e. the lighter the surface, the more energy is reflected by the Earth's surface, this factor is constantly being altered around the world, with more land being taken up by construction work, glaciers melting and so on. It is this factor that I believe will prove to be the most significant factor in increasing the global average temperature.

Some typical values are 0.15 to 0.25 for water, 0.4 to 0.95 for snow, 0.2 to 0.4 for ice and 0.15 to 0.5 for forest.

Basically, as the global average temperature increases, the less snow and ice there is around the globe, so huge areas could have their albedo significantly changed, for instance their might be areas in mountain regions which have fresh snow all year round, keeping a permanent albedo of between 0.4 and 0.95, so if temperature increases to the point where this snow pack no longer exists, then that surface area absorbs more solar energy, so the rising temperature actually causes a secondary effect which accumulates to raise temperatures even higher.

The problem with this is it is very hard to counter act with geo-engineering, in fact the only real way is by physically altering the colour of huge areas of the earth's surface. I've heard suggestions that include lightening the road systems around the world, adding mirrors to roofs and such like, but these would be enormous economic investment ventures, and would have very little tangible effect, given this would alter <1% of the Earth's surface while >1% is changing due to melting snow packs.

Sadly, I think the reality is that the world will continue heating until the carbon cycle means the level of carbon in the atmosphere begins to decrease, unfortunately, carbon remains in the atmosphere for between 200 and 500 years.

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