more on climate change

Listened to an interview with Sherwood Roland, a Nobel Prize-winning scientist, on RN, which has added to my education re the subject. Apparently there are six greenhouse gases, which for my sake I'll name. Carbon dioxide (C02), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SH6). CO2 first began to be measured back in 1958, the finding being around 315 ppm. Now the measure is around 379 ppm. Roland is saying we can’t let it get above 450-500ppm, but that seems a long way off, and with positive and negative feedbacks coming into effect (eg a concomitant increase in water vapour in the atmosphere, which will cloud the issue ho ho, and also increases in vegetation which will absorb CO2) predictions again become difficult.
Apparently a two degree warming is used as a benchmark figure – beyond that, catastrophe. But of course this figure is highly disputed even among climatologists. In any case we’re up around 0.8 increase now, and there should be another .5 or so coming out of human activity even if there were to be a major turnaround tomorrow, according to Roland. He believes there needs to be 50-60% reductions in fossil fuel emissions – Kyoto asks for about 5%. I need to look more into the whole Kyoto thing.