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Last Build Date: Tue, 23 Jan 2018 17:10:52 +0000

 



Comment on The claim of reduced uncertainty for equilibrium climate sensitivity is premature by Peter Cox

Tue, 23 Jan 2018 17:10:52 +0000

Hi Folks I fully expect people to be sceptical about our study (as it promises a lot for apparently so little), but unfortunately some of the views above are based-on a critique which misrepresents what we actually did. I would therefore like to correct some misconceptions so that people can at least be sceptical about our work for the right reasons...:-). 1) We use an Emergent Constraint (EC) approach, which means that we use GCMs to determine the relationship between variability and ECS. The Hasselmann model is merely used to inform our search for the most appropriate metric of variability. 2) We do not assume the Hasselmann model is a good representation of the historical warming. Of course it isn’t and we say that very clearly in our paper: “The constant heat capacity C in this model is a simplification that is known to be a poor representation of ocean heat uptake on longer timescales. However, we find that it still offers very useful guidance about global temperature variability on shorter timescales”. 3) We reduce the impact of long-timescales on our EC by linearly-detrending in a 55 year window (though other window-widths work almost as well), and then calculating a metric of variability (PSI) that is independent of the heat capacity. This will work so long as the effective heat capacity is near constant within the window, and that holds so long as the window separates the fast (~5 years) and slow (a few hundred years) timescales of complex climate models (see for example Geoffroy et al., 2013). 4) We do not ignore slow feedbacks. These are included in the ECS values diagnosed from the complex climate models. However, variability is a constraint on ECS most likely because the uncertainty in ECS across current climate models is dominated by fast feedbacks (notably clouds), and these affect the variability. Obviously, slow feedbacks would not be seen in short-term variability, but these are not the main cause of uncertainty in ECS. 5) As Kevin Cowtan rightly says, we did check that the coverage of the observational data in HadCRUT4 did not affect our emergent constraint. We also checked that using different observational datasets (NOAA, Berkeley, GISTEMP) gave similar results (results shown in Extended Data). If you still have questions please do not hesitate to get back to me. We are attempting to do objective climate science, rather than to support a particular advocacy position, so direct communication would be greatly appreciated. Thanks Peter Cox



Comment on The claim of reduced uncertainty for equilibrium climate sensitivity is premature by Robert McSweeney

Tue, 23 Jan 2018 16:54:03 +0000

A minor point, but the Guardian article linked to here isn't written by Guardian staff. It's a wire story written by the news agency Agence France-Presse (AFP).



Comment on 2017 temperature summary by Nemesis

Tue, 23 Jan 2018 16:29:36 +0000

To these funny, beloved deniers: CO2 is good for the plants, we are heading towards a wonderful future, we will grow wine and strawberries on Greenland, we will welcome millions and millions of climate refugees as cheap labour in Europe and elsewhere, Mr. Trump and alike will surely get what they want and deserve: More heat. Yeah, Karma is a funny thing I tell you. Btw: Tomorrow we will get up to +16°C in Germany, gnahahaha, in the midst of Winter :'D Yoh yoh, that's just weather, everyhing is fine, wonderful, please, never stop denying, beloved deniers, Hell needs to be Hot, Hotter. Please, make Hell real Hot. And I mean it 3:-(



Comment on 2017 temperature summary by Nemesis

Tue, 23 Jan 2018 15:20:35 +0000

About Mr. KIA, Keith Woollard et al: Hahaha, I'm so happy that I'm done with funny deniers for some years now :'D Their funny game goes like this: One jumps out of the bush, throws in any completely irrational "comment" and when that "comment" has been disproved, then he ducks and another one jumps out of the bush and throws in another completely irrational "comment" :'D Yeah, I know that gamez in and out. But hey, I love you, brainf*s, because YOU are my guarantee, that the funny system will fall quickly 8) So, PLEASE, go on for goodness sake, please, never stop denyin, never ever stop, we are almost done. Thank you, beloved deniers, thank you very much for serving my purpose: The fall of greedy, ignorant capitalism. It will happen, I swear, thanks to endless ignorance and denial, it will happen 100%. So, thank you, thank you, thank you, beloved deniers! Best wishes, Nemesis



Comment on Forced Responses: Jan 2018 by MartinJB

Tue, 23 Jan 2018 15:01:49 +0000

Scott (@238): It's worth noting that a well-designed (always the rub...) cap-and-trade scheme would actually encourage just the kind of activities that you are advocating. I'm not minimizing the challenges in creating a robust scheme, but it should certainly award sectors that can provide relatively inexpensive carbon sinks.



Comment on Forced Responses: Jan 2018 by Kevin McKinney

Tue, 23 Jan 2018 14:25:12 +0000

Mr. KIA, #237--
...my guess is that subsidies are what is preventing EVs from becoming more popular.
Right, because everybody likes to pay more for a given product, and as the price goes up demand increases.
If the subsidies started to dry up, the EV producers would have to cut costs of the vehicles so they are affordable...
Right, because price is purely a function of executive fiat; companies can charge whatever they like, whenever they like. "Cost structure" is just a myth they invented to rip off customers.
...and also, improve performance so people would want to buy them.
Right, 310 miles of range and 0-60 in 5.6 seconds is pretty pathetic.
Right now they are less than 1% of sales in the US. They will continue to be irrelevant until they improve performance and cut cost.
Right, because 200,000 US units in 2017, up from 160,000 units in 2016, is an annual growth rate of a lousy 25%, and at that rate, EVs wouldn't even be half of the 18 million or so US annual sales for... 17 years. And in 20, that would be 100% of the market. Hmm. Maybe that point isn't right.



Comment on 2017 temperature summary by Matt Bennett

Tue, 23 Jan 2018 13:59:03 +0000

Keith, I think we ‘need to explain things a little more simply’ for YOU! There’s virtually no distinguishable error bar visible at that scale on the ‘modern temperature record’ section of that graph, let alone one matching 22K yr ago!! See that big vertical straight line?...... the initial blue quarter of it.. need I continue?... the marked ‘0’ was over 2000 years ago.



Comment on The claim of reduced uncertainty for equilibrium climate sensitivity is premature by Spencer

Tue, 23 Jan 2018 13:58:48 +0000

Gilman at #11 — can’t really blame the Guardian when the commentary in Nature itself announced “A compelling analysis suggests that we can rule out high estimates of this sensitivity.”



Comment on Unforced Variations: Jan 2018 by mike

Tue, 23 Jan 2018 12:20:31 +0000

Just a quick look at papers at GCP: Trends in the sources and sinks of carbon dioxide https://www.nature.com/articles/ngeo689 "In the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year has likely increased, from about 40% to 45%, and models suggest that this trend was caused by a decrease in the uptake of CO2 by the carbon sinks in response to climate change and variability. Changes in the CO2 sinks are highly uncertain, but they could have a significant influence on future atmospheric CO2 levels. It is therefore crucial to reduce the uncertainties." First signs of carbon sink saturation in European forest biomass http://www.globalcarbonproject.org/news/CarbonSinkSaturation.html "European forests are seen as a clear example of vegetation rebound in the Northern Hemisphere; recovering in area and growing stock since the 1950s, after centuries of stock decline and deforestation. These regrowing forests have shown to be a persistent carbon sink, projected to continue for decades, however, there are early signs of saturation." Increase in observed net carbon dioxide uptake by land and oceans during the past 50 years http://www.globalcarbonproject.org/news/CarbonSinkIncreases.html "Our mass balance analysis shows that net global carbon uptake has increased significantly by about 0.05 billion tonnes of carbon per year and that global carbon uptake doubled, from 2.4 +/- 0.8 to 5.0 +/- 0.9 billion tonnes per year, between 1960 and 2010. Therefore, it is very unlikely that both land and ocean carbon sinks have decreased on a global scale." Mike says: The question of how the terrestrial carbon sinks are functioning is a lively area of science and makes for interesting reading if you have the time. Noisy number: January 14 - 20, 2018 408.16 ppm January 14 - 20, 2017 406.02 ppm 2.14 ppm increase in yoy comparison. I think 2017 number carrying a little residual EN bump. Cheers Mike



Comment on The claim of reduced uncertainty for equilibrium climate sensitivity is premature by Ray Ladbury

Tue, 23 Jan 2018 12:10:34 +0000

Dan DaSilva, Thanks for the comic relief. We can always count on you for a laugh! Zebra, Tamino has looked at extreme temperature and precipitation events to some extent and found that it looks as if the distribution mainly shifts toward the right with the width remaining about the same. Nonequilibrium is not something physics does particularly well. Near equilibrium, probably a little better, and that is probably closer to what we have.