Ian K said...
I'm not a climate scientist, ( i've got an internet browser), but I've been meaning to ask one "How confident are we that the CO2 hasn't hit 385 ppm in the past 700,000yrs?"
I read somewhere on the internet that ice cores from Vostok have a resolution of only several hundred years. ie. The bubbles aren't synchronised in their closure. If so, (here's my hypothesis ) if a volcano let go a similarly large burst of CO2 500,000 years ago it would barely show up as a blip in the ice cores, provided the climate was able to recover within 100 yrs. Does that sound feasible?
At the moment, according to the www, the earth seems to be coping pretty well. Although humans release 4.5 ppm of CO2 into the atmosphere each year we only measure a rise of 1.5 ppm each year. Where is the excess stashed I wonder? So if we went totally nuclear tomorrow the CO2 would head back to its pre-industrial levels at 3ppm per year.
Sometimes i wish the inner-net was never invented!
Yes, we're very very confident there hasn't been as high a CO2 levels in the past 700,000 years
at least.
Volcanoes simply cannot release an amount of CO2 that would globally raise the CO2 to todays levels. Simply not possible. Yes there have been eruptions that have caused changes in the global climate, but much of this was probably due to methane; in modern times the best the
total global total volcanic eruptions could do was contribute less than a hundredth of the observed rise in CO2.
The actual net increase of CO2 is now over 2ppm per annum. About 40% of the human emmissions are absorbed by natural processses - mostly the oceans. However the longer we leave things the more the ocean absorbs, meaning it approaches saturation. Once (if) this occurs, no more net CO2 removal, and hence we'd add (at current levels) about another 0.7degreeC to our warming. In fact this is the exact reason why we reckon we're locked into at least double the warming we already have. We've already added around 0.8degC, then the ocean alone could potentially deliver almost that again when things come into balance, and then we havent even talked about removing the dirty aerosols (which we will as we clean up industry as we attempt to tackle CO2 increases) that current "reflect" about 2/3degC... so all up, we pretty much have 2degC warming in the bag. Well done world!
Errr... i think this has gotten way too far from windsurfing - and i got 21 knots SSW out there calling me and thats one siren-song this bloke cant resist...