The point is not so much the CO2 tonnage in absolute terms as the amount of CO2 which the biosphere can handle without getting itself seriously out of whack. For instance the overall percentage of CO2 in the atmosphere has increased by about 70% since the pre-industrial era. This is an astonishingly rapid change in biological terms and could well be unprecedented in the last billion years. (No-one really knows for sure whether such a rapid CO2 escalation has ever happened in the past but it seems improbable in the past few hundred million years at least). If the CO2 level were to increase by 70% more gradually, say over a period of ten thousand years or so, it is quite likely that the biosphere could adjust without a mass extinction because this is a time scale more suitable for evolution to work its magic in.Walker wrote:1. Does the actual amount of human contributions to the atmosphere exceed natural contributions? I don't know.
Whilst this is true the overall vegetation cover on the planet has plummeted dramatically over the past two centuries. I don't have the figures to hand but this is not in dispute.Walker wrote:respiration of plants. Many areas of the planet are as forested as they ever were. Many areas
Sure. Whilst there is some small variation in CO2 levels from region to region our weather systems are such that such variations are negligible in the wider scheme of things. It is certainly meaningful to speak of a global percentage level of CO2.Walker wrote: The gas exchanges affected by localized pockets of deforestation could well be absorbed into the huge atmosphere, could they not?
It's a totally different system but sweet fuck-all is known about the role of the marine biosphere in the carbon cycle. Everybody knows it's hugely important but nobody really knows how the whole system functions together, which is why the future predictions of the climate scientists are so wildly uncertain. However they seem to be pretty unanimous in their agreement that the acidification of the marine biosphere which an increased absorption of CO2 is causing is likely to have some serious long-term consequences. Nobody knows what these consequences might be and anybody who claims to know is full of shit because the future of evolving systems simply cannot be predicted.Walker wrote:The ocean could be compared to the atmosphere, could it not?
Interestingly the country making the most rapid progress in replacing its lost forests is China.Walker wrote:Speaking of radio blurbs, a few months ago I heard the tree population has been recalculated. 6 trillion trees. Much larger than previously thought.