excursions in geologic time scales -- "snowball earth" vs. the Cretaceous (when there was no ice at the poles) ... push the climate to a place it has not been before,
Yea..even the places it's been before are pretty awful, for a human. I don't think this is a local unstable point, far from it; our current climate seems very stable. But, over those epochs, we've built up a huge store of high-energy carbon, and as the CO2 left the atmosphere since those epochs, the ecosystems we have right now are not accustomed to high-greenhouse climates. So, the fact that we're now suddenly digging up what amounts to eons of free solar energy, and are burning them all at once, is a problem. Will the earth burn? No, that's an unlikely outcome. Venus is Venus because it never developed life. Will the Earth burn *us*? Maybe. Totally plausible possibility, though still unlikely. Will the Earth burn the ecosystems that civilisation (rather than humanity, per se) depends on? At this rate, probably. We have fallbacks; go all-in on solar & nuclear for energy and biotech for efficient, lower impact food/med production, and use nuclear/biotech to cook up some hyperefficient carbon-capture system to try and roll back as much as we can. I'll just point at this, then, as an example of what I find exciting in this space: http://www.plosone.org/article/info%3Adoi/10.1371/journal.pone.0109935 - That's some staple elemental inputs, CO2, and electricity ONLY, and a massive sequestration effect per volt/meter using bacteria. Outputs are hydrogen and acetate, useful energy/industrial chemicals. Anyways, just to say doom and gloom is rarely useful, but ostrich-heads are worse than useless. Action can be beneficial, and action need not be "live like a peasant", it can be "change your tech and culture to live comfortably or even abundantly with less impact". As to on/off topic-ness, it's off topic. But this list has seen people bitching about who is and isn't a real native American, so I find this at least engaging and interesting. On 24/10/14 14:40, dan@geer.org wrote:
For the purpose of this note, I'll stipulate that global warming is happening without arguing why. The question for science would be whether it has a positive feedback loop, as it would if rising temperature releases, say, 10% of the carbon locked in permafrost. Given the wild temp excursions in geologic time scales -- "snowball earth" vs. the Cretaceous (when there was no ice at the poles) -- it is reasonable to imagine that some excursions have a phase where the feedback is positive and thus if the temp heads either north or south its velociity will, for natural reasons, accelerate as the excursion grows more extreme. That implies that the present time is an unstable equilibrium, thus our imapct, whatever it is, seems likely to be an initiator or a potentiator but not a cause in the classical sense of, say, a dose-response curve.
Put differently, I don't believe that we (humans) can push the climate to a place it has not been before, but we can change the clock. One might then ask what government has your confidence in its being capable of managing a comprehensive program of compensatory global cooling and what powers would be required to enforce same?
What this topic has to do with this list is unobvious.
--dan