Carbon off setting may need a re-think

On BBC radio 4 yesterday morning (15/12/2006) I heard that planting forestry in order to off set emissions of CO2 may well be a waste of time, atleast if the trees have been planted outside of the tropics where the rainforests are situated.

More than simply being a waste of time, the forestry may actually contribute more CO2 to the environment, due to process of respiration of plants when they are not photosynthesising, such as at night time or when levels of sunlight are too low for this process to occur. As we in the more exreme latitudes would understand, the length of days varies widely here as opposed to the tropics where days length may well be shorter compared to us in the summer months but they are at least more stable throughout the year.

Another reason why trees are beleived to contribute to global warming is that they absorb the suns radiation and in areas where snow and ice would usually reflect some of that radiation away from the earth, the trees may well cover or even inhibit the formation of snow. So please Scandanavia, forget the trees, give us snow!

This throws up the question of, when attempting to offset CO2 emmissions, whether one should put money into one those funds that claim to purchase solar panels and energy saving light bulbs, of which I never really had much trust, or should the money still be put into forestry planting schemes and of course can we ensure that the trees are planted in the correct place?

Read: http://news.bbc.co.uk/2/hi/science/nature/6184577.stm for the full story.