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Environment & Energy
In reply to the discussion: Time to go on the record [View all]GliderGuider
(21,088 posts)108. Here are a couple of pertinent comments from Neven's blog
http://neven1.typepad.com/blog/2012/09/models-are-improving-but-can-they-catch-up.html
And this:
The August CO2 concentration was 392.41
imho, when the history of AGW comes to be written one of the major mistakes noted will be the over reliance and too much emphasis being put on computer models. Too inaccurate and too easy to attack by skeptics. Hansen and Alley seem to have realised this and now only focus on the paleoclimate record - after all the earth is the best model for the earth. IIRC antarctic ice sheet started to appear when C02 dropped below 450ppm. From current observations, summer arctic ice disappears at approx. 390-400ppm. GIS presumably disappears somewhere between these two: 400 and 450ppm. Do we need to know anymore than these three numbers?
And this:
Those paleo-data seem to indicate that 400 ppm (Pagani et al) was not crossed the past few million years, or even the past 15 million yrs (Tripati et al), with sea level 15-25 meters higher and no GIS and WAIS, or at least much smaller.
Hansen himself thinks 350 ppm (crossed in about 1988) was the point when Arctic sea ice started its self-reinforcing decline, or maybe even earlier. Because of the inertia in the system we're seeing the effects of that today, with much more in the pipeline. To have prevented the Arctic decline, and the polar amplification as a result of that, we should have probably kept the concentration at least below 350 ppm.
Hansen himself thinks 350 ppm (crossed in about 1988) was the point when Arctic sea ice started its self-reinforcing decline, or maybe even earlier. Because of the inertia in the system we're seeing the effects of that today, with much more in the pipeline. To have prevented the Arctic decline, and the polar amplification as a result of that, we should have probably kept the concentration at least below 350 ppm.
The August CO2 concentration was 392.41
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I'm guessing you've set out your balloon project somewhere on DU already
muriel_volestrangler
Sep 2012
#12
Sometimes, private efforts really can be as good, and even better than the government's.......nt
AverageJoe90
Sep 2012
#68
I've a couple of questions that keep rattling around in my poor addled head...
a geek named Bob
Sep 2012
#72
Re: "My position is that we would probably be better off in the long run if everyone took a break"..
AverageJoe90
Sep 2012
#73
An opportunity to become sustainable for the first time in our species' history.
GliderGuider
Sep 2012
#64
The system you describe does not exist. If it did you could colonize the galaxy.
joshcryer
Sep 2012
#75
My prediction for an ice-free Arctic year-round? 2040, maybe 2060 if we're lucky.
AverageJoe90
Sep 2012
#25