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Comments for RealClimate



Climate science from climate scientists...



Last Build Date: Wed, 28 Sep 2016 10:59:44 +0000

 



Comment on The Snyder Sensitivity Situation by Philip Brohan

Wed, 28 Sep 2016 10:59:44 +0000

The GAST reconstruction has surprisingly small uncertainties (2-sigma range of +-1.8C at the LGM). The two obvious contributors to the uncertainty are the structural biases in the proxies and the sampling error from estimating GAST from 5-61 SST observations. Structural bias uncertainty estimate comes from three independent proxy types, each with a 2-sigma of 3C, so the 2-sigma on the mean is about +-1.7C. Sampling error is hard to estimate, but eyeballing extended data figure 5 suggests that in the PMIP simulations it's enough to increase 2-sigma from about +-2.5C to about +-5C - that's about +-4C Combining in quadrature suggests a 2-sigma uncertainty of +-4.4C for the LGM uncertainty, which doesn't seem ridiculous for a reconstruction based only on SST proxies - bigger than the AR5 estimate of +-2.5C, but that estimate is based on much more data. How do we get an uncertainty of +-1.8C - where is the precision coming from?



Comment on Can a blanket violate the second law of thermodynamics? by Mack

Wed, 28 Sep 2016 10:49:21 +0000

Jim Eager @117 Your revisitation of comment #97 to better address incoming solar energy at the TOA...with.."Perhaps it will help Mack to finally see the light,as it were."..seems to have got you into an even more confused state, Jim. Even Digby Scorgie pulls you up .."you mean TOA, not TOE, don't you?" I hope to clarify and enlighten this issue for you , if the moderators will allow my comments, here... http://principia-scientific.org/is-no-greenhouse-effect-possible-from-the-way-that-ipcc-define-it/#comment-11469



Comment on Why correlations of CO2 and Temperature over ice age cycles don’t define climate sensitivity by Kevin McKinney

Wed, 28 Sep 2016 10:09:29 +0000

Jeff, thanks for dropping by. Just a clarification (I know you know this, but not all our readers will!): the fact that the ocean was colder during glacial periods by itself explains only about 10% of the CO2 change. Dynamical, biological and chemical changes that go *along* with the temperature change are required to explain the bulk of the changes in CO2. –eric
I didn't know that, and find it quite interesting. What are the other (proposed?) feedbacks? And what levels of uncertainty attach to the various contributions? Pointers, perhaps, to some lit on this?



Comment on Why correlations of CO2 and Temperature over ice age cycles don’t define climate sensitivity by dp

Wed, 28 Sep 2016 09:08:32 +0000

About direct heat emissions I have seen a figure quoted of 0.1C or 0.3% of radiation from the sun. Is this correct?



Comment on Can a blanket violate the second law of thermodynamics? by Alfred Jones

Wed, 28 Sep 2016 08:24:42 +0000

MikeR, I couldn't believe you so I checked. Here's the cut-and-paste so others don't have to scroll through the goop. Mack said, "then you blather on further about eclipses. Aaahahahahahaha…sorry mate….Eclipses are where the Moon interposes itself between us and the Sun. When the Earth interposes itself between Sun and Moon its called, phases of the Moon. Ever heard of that phenomenon.? It occurs much more commonly than eclipses…and there are even occasions where absolutely no sun at all strikes (spelling OK) the Moon’s surface. You could be looking through the wrong end of your telescope MikeM…but I’ll just put it down to brain-fag on your part. No need for an apology."



Comment on The Snyder Sensitivity Situation by Tony Weddle

Wed, 28 Sep 2016 08:23:55 +0000

Wow, wishful thinking by Nic Lewis on low ECS, given that we're at 1.3C (1.8C without aerosols) on a 40% increase in CO2 (though more for CO2e). Anyway, just wanted to ask about the human (and other species) consequences of an ESS of 4.5C to 6C, versus an ESS of 9C. Should we (on behalf of future generations) be relieved that 9C is almost certainly far too high, and future generations might only get 6C (or even 4.5C)?



Comment on Unforced variations: Sep 2016 by Alfred Jones

Wed, 28 Sep 2016 07:10:15 +0000

Killian, Scott and I exchanged non-disclosure agreements and explanations of agricultural projects. I think my path is better. (predictable, eh?) Perhaps Scott feels his path is better. In any case, I'll tell you that permaculture is not the "one and only" way to go. Perhaps someday we'll GMO corn, wheat, soybeans and the rest into perennials. (perennial carrots?!?) Dunno. I will say that both Scott's and my techniques would work (if they work) on humungous farms, and so would perennial versions of grains. There's no reason we can't continue to gather into cities while ginormous farms supply most of our calories. Cities and huge farms have tremendous efficiency. Scott's right. There's more than one way to eliminate ploughing. He's also right in that future generations will improve on what we do today. Our job is not to build perfection out of whole cloth, but to maintain conditions where productive weaving is still possible. It's not our job to stop mining phosphorus et al, but to ensure that the mines don't run out before our descendants create truly sustainable systems. We do not need sustainable systems yet. We just need to keep from going off the cliff. The perfect is the enemy of the good. Your stance seems to be, "We must kill off or impoverish most everybody because otherwise we won't win a [totally irrelevant] Gold Medal." Good luck with that.






Comment on Unforced variations: Sep 2016 by Tony Weddle

Wed, 28 Sep 2016 03:49:19 +0000

In Hansen's "better graph" post, he talks about the surface temperature rise being "only" about 0.1C, between true pre-industrial and the 1880-1920 base line that he uses. However, in this article, last year, Michael Mann estimates the warming to be about 0.2C between true pre-industrial and 1870. These aren't exactly the same periods but there still seems to be a discrepancy here. Can someone shed some light on this difference? As an aside, it's surprising that Hansen characterises a 0.1C rise before 1900 as "only", when he has determined that a 1C rise over pre-industrial would be dangerous. His 12 month running mean is at 1.3C above 1900 and an extra 0.1C would put it at +1.4C, which is very close to the 1.5C aspiration mentioned at Paris.



Comment on Can a blanket violate the second law of thermodynamics? by Chris O'Neill

Wed, 28 Sep 2016 03:47:44 +0000

Mack:
gases do not add energy
Mack obviously doesn't know that gases (and everything) generates radiation: "All matter with a temperature greater than absolute zero emits thermal radiation." Mack:
Stephan has obviously forgotten..
Arrogance is the solution to all of Mack's scientific problems.