Arguments
Recent Comments
Prev 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 Next
Comments 37701 to 37750:
-
StBarnabas at 05:06 AM on 12 March 2014Climate change and sensitivity: not all Watts are equal
What uniform heating? i am struggling with the units here. The y axis is fine. Uniform heating to me is a constant input of Watts (dQ/dt =k (J/S)) which into an adiabatic system would prosuce a linear rise. Is this uniform heating d2Q/dt2 =k? A few ODEs might help me understand this a bit better - obviously the models are very complex but a simple state spaace model or equivalent simple ARMA proccess would help my small brain.
-
wili at 05:01 AM on 12 March 2014Climate change and sensitivity: not all Watts are equal
This seems to be the crucial part (from "below the fold"):
" Multiple lines of evidence are now consistent showing that the climate sensitivity is very unlikely to be at the low end of the range. The consequences of climate change are thus likely to be towards the more damaging end of the estimates, unless we take action to quickly reduce our emissions."
OT question: Has anyone else had trouble getting onto RealClimate recently? Are they shut down for maintanance, or under cyber attack?
-
John Hartz at 04:28 AM on 12 March 2014GWPF optimism on climate sensitivity is ill-founded
All: Russ R's most recent comment directed at Tom Curtis was deleted because it was inflamatory and insulting. Russ R may soon be recusing himself from posting on SkS.
-
jja at 03:58 AM on 12 March 2014GWPF optimism on climate sensitivity is ill-founded
Another near-term feedback is the reduction ocean-spray DMS aerosols that will contribute .2-.4C additional warming and the recent model results of decreased low-altitude cloud cover under warming scenarios (additional .2-.5)
It is clear that we have already passed the 2C pre-industrial threshold, even if we halted all emissions today.
-
GWPF optimism on climate sensitivity is ill-founded
Russ R. - If you want examples of groupthink and echo chambers, take a look at WUWT, at Climate Audit, at JoNova, Bishop Hill, etc. Where the presentation of facts, of peer-reviewed papers, of statistical significance are all met with jeers, insults, ad hominems, etc. Persisting with facts on those venues tends to result in moderation.
On SkS, by contrast, jeers, insults, ad hominems, and sloganeering are met with facts, peer-reviewed research, and discussion of statistical significance. And commenters persisting in posting nonsense are moderated. Compare and contrast, note the distinction in content. Personally, I prefer fact-based discussions such as the ones here.
Your personal experience seems unhappy - I would point out (IMO) that you reap what you sow.
-
jja at 03:35 AM on 12 March 2014GWPF optimism on climate sensitivity is ill-founded
If we halted all CO2 emissions today, according to the AR5 Frequently Asked Questions 12.3, temperture would continue to rise for "several tenths of a degree" due to sulfate emission reductions.
Then it would take several decades for methane emissions to return to pre-industrial levels.
But we know that the loss of arctic sea ice between 1979 and 2012 has contributed a total of 25% of the total anthropogenic forcing. We also know that this trend will continue through the next several decades.
In addition to the aerosol and albedo feedbacks that will occur during these next few decades, the additional warming will produce carbon cycle feedbacks. These feedbacks are,- The collapse of the Amazon rainforest
- The rapid thaw of arctic permafrost, and
- An additional slowdown of the Meridional Overturing Circulation
All of these factors are not modelled in the AR5 scenario and will produce significant warming over the next several decades.
-
bibasir at 02:00 AM on 12 March 2014A Hack By Any Other Name — Part 4
Fascinating story. I had no idea how much work has been put into the site. I look forward to the next episodes. A book that might be of interest is The Cuckoo's Egg: Tracking a Spy Through the Maze of Computer Espionage by Cliff Stoll
-
Rob Honeycutt at 01:36 AM on 12 March 2014GWPF optimism on climate sensitivity is ill-founded
Russ... You may not have been around long enough to have noticed that we've had quite a few more prominent scientists posting here. In particularly contentious cases we assign a single SkS commenter to the discussion as to not overwhelm the guest.
What SkS does not have patience for are those who break the rules that are laid out in the commenting policy. Those get snipped or deleted or banded depending on the severity of the infractions.
And, if you think it's bad here, you might take a day and pose as an advocate for action on climate change on sites like WUWT, JoNova, Curry, or any of the many other lightly or unmoderated "skeptic" sites.
-
Russ R. at 00:49 AM on 12 March 2014GWPF optimism on climate sensitivity is ill-founded
Albatross@30,
"Where is Lewis on this thread? He is undoubtably aware of it, yet he is posting on sites run by extremists and fringe elements."
If I may offer some constructive advice, you might want to scan back through the history of comment threads here at SkS and look objectively at the "hospitality" that has been shown to visitors (by both regulars and moderators).
If guests don't feel welcome, SkS won't find many guests coming to visit, and it will run the risk of devolving into an echo-chamber of groupthinkers nodding vigorously in agreement with one another while actual debate takes place elsewhere.
You can judge for yourself whether or not it's already too late. As it stands today, the only visitors SkS seems to attract are indistinguished nobodies like me.
-
Tom Dayton at 00:18 AM on 12 March 2014The Editor-in-Chief of Science Magazine is wrong to endorse Keystone XL
Brooks, your sentiment is correct, but your number is not. Keystone will yield only 35 permanent jobs. Yes, 35. Not 3,500. Not 350. 35. Really. The reason the oil industry likes pipelines is that they are cheap. "Cheap" largely due to the low need for labor. The cheapness is the reason industry wants the pipeline. If industry and Marcia McNutt were correct that the cost of the tar sands oil does not depend on whether it is transported by pipeline or rail/truck, then industry would not be fighting for the pipeline. Instead, the industry's fight for the pipeline is unequivocal evidence that the pipeline will reduce the cost of the oil and therefore speed the production and use of the oil.
-
Brooks Bridges at 23:57 PM on 11 March 2014The Editor-in-Chief of Science Magazine is wrong to endorse Keystone XL
I see no comment regarding the benefits to America of this pipeline. From all I've read, the dilbit goes to to our southern ports where it is refined and then sold to the highest bidder - which, with our current oil and gas boom won't be America.
The Congressional Budget office says that besides refineries, there will be 3,200 permanent jobs - a drop in our employment bucket. Given the northern part of the pipelines have already had, I think, 11 spills and the company continues to do nothing to improve pipeline safety, we can look forward to many more spills.
So how does this make any kind of economic sense for America? Canadians and Koch brothers make billions of dollars profit and we get to clean up their spills and the oil goes to other countries.
-
Mighty Drunken at 23:55 PM on 11 March 2014The Extraordinary UK Winter of 2013-14: a Timeline of Watery Chaos
A statistic I found interesting in regards to this Winter's weather in the UK is the number of times the Thames Barrier, a flood defense, had to be raised.
As this page shows the number of times it has been used has been increasing sharply.
It was closed four times in the 1980s, 35 times in the 1990s, and 135 times since 2000, 50 in the 2013/2014 winter alone.
-
Paul Pukite at 22:49 PM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
I do not understand how Lewis is given any deference. The fact that 6 years of data results in his analysis dropping the TCR that much can not be right. Nature does not change abruptly like that. A CO2 model of natural availablity that uses SOI, volcanic aerosols, LOD, and TSI, and other natural cyclical terms can predict 50 years of rising temperature including the fluctuations, based on a training interval that only goes to 1960.
I suggest to keep on confronting Lewis. He obviously doesn't like to be called on his cherry-picking work:"WebHubTelescope needs to check his facts. "
http://www.climate-lab-book.ac.uk/2014/gwpf/#comment-104601
-
Tom Dayton at 22:23 PM on 11 March 2014The Last Interglacial Part Five - A Crystal Ball?
renewable guy: See also Shakun et al. Clarify the CO2-Temperature Lag.
-
Tom Curtis at 22:02 PM on 11 March 20142014 SkS Weekly News Roundup #10B
Chriskoz @14, in Qld, there is a 44 c per kWh feed in tariff for those who installed their solar panels prior to a change of regulation under the new (coallition) government. There is a 8 c per kWh feed in tariff for other domestic solar generators, which will expire on July 1st. After July 1st, the 44 cent feed in tariff will remain in effect for those eligible, but the 8 cent rate will cease to exist. Instead domestic producers will need to "negotiate" a feed in tariff with their retail supplier. As in all cases where very small suppliers attempt to negotiate with large retailers, that will supress the feed in tariff well below the whole sale rate of supply from other sources. IMO, it is a rather transparent attempt by the coallition government to kill renewable supply from domestic producers. It would be hard to argue otherwise given that:
- The 2008 wholesale spot price for electricity in Qld averaged 8.8 cents per kWh;
- The 2012/2013 retail price in Qld was 25 cent per kWh; and
- The new regime is predicted to reduce retail prices, presumably by reducing the feed in tariff (first link).
All this from a government that is increasing coal production with indecent haste.
Under most circumstances, I am very proud to be a Queenslander, but Campbell Newman is making that very difficult at the moment (and don't get me started on his introduction of guilt by association, punishment by secret tribunal, and winding back of the seperation of powers and the rule of law).
-
chriskoz at 20:55 PM on 11 March 20142014 SkS Weekly News Roundup #10B
Tom@14,
I wonder what's the current status of feed-in in QLD. What's the mandated FiT for early adopters and how long are their contracts lasting?
In NSW, the FiT by previous govs (labor) were as incredibly high as $600MWh. They are mandated until end of 2016, creating the classic perverse incentives you describe. New govs (libs in 2011 I believe) immediately ceased the contracts so such overpriced FiT (because the industry was burning out on overdrive) and they even wanted to retospectively scrape the existing contracts: a very bold move, illegal IMO. But they met with the rage of contractees, so did not succeed. So, we need to wait for more than until the perversive FiT expire. I understand that the early adopters are elligible for the generous subsidies. But in 6this case it would be much better for the environment if those investors settled with the govs for some lump sum of money in exchange for scraping the perversive incentives. I've heard for example, that by turning on a 2kW AC unit on top of your peak-hour demand, you create ~$7000 cost for the retailer who must upgrade the network and bid the appropriate evergy amount at the extremal price, usually from gas-powered supplier to satisfy the demand. This situation could be perhaps remedied by a solid peak-demand charges. But instead, the retailers are recouping their losses by increasing fixed charges.
Meanwhile, the true FiT for post-2011 home investors was mandated by the govs at $77MWh minimum, which was barely above the coal-fired baseload wholesale price of ~$50MWh. That was before carbon tax. For some reason, after CTax last year, the minimum FiT dropped to $66MWh, contrary to my expectations, so perhaps it is already at or below baseload wholesale price + CTax. And guess what: my retailer (Energy Austratia) pays me the exact minimum, not a cent more.
As you see, lot of scenarios in energy market are swayed by politics and private greed of all players involved. There is very little actions/policies with the top goal of reducing GHG emissions in mind. Rather, the whole energy buiseness model does work in opposite direction.
-
Rob Painting at 16:49 PM on 11 March 2014The Last Interglacial Part Five - A Crystal Ball?
renewable guy - See this post by Chris Colose: Milankovitch Cycles.
-
renewable guy at 16:14 PM on 11 March 2014The Last Interglacial Part Five - A Crystal Ball?
I remember an article in SKS where it was stated that the orbital forcing did not explain the warming coming up out of the last ice age. It (orbital forcing) supposedly would only explain about 10% of the warming. The rest would be positive feedbacks I assume. Loss of albedo and co2 coming up out of the oceans. I would like some help getting to that article that explains just that ratio. It helps to emphasize that a small nudge of the climate can make a much bigger response.
-
Tom Curtis at 14:15 PM on 11 March 20142014 SkS Weekly News Roundup #10B
scaddenp @13, absolutely agree about the need for whole sale pricing of domestically generated electricity sold back into the grid. Indeed, more than retail pricing (mandated in some Australian jurisdictions) has the perverse effect of providing a maximum incentive for the domestic user to minimize use in the daytime when they are generating power on site, and maximizing use at night when there is minimal renewable supply. That is, it maximizes inefficiency in using solar power, and minimizes the emmisions reduction from the extra generation.
The only caveate I would place on the whole sale pricing is that renewable and non-renewably sourced energy are differently priced when sold to the consumer. At least in Queensland, you can pay a premium to have a significant proportion, or 100% at a higher premium, of your energy from carbon free sources. The "sell back" price of domestically generated solar electricity should also reflect that premium. That could be accomplished by the sell back price matching the average whole sale price of renewable power, rather than the average price of power in general.
-
citizenschallenge at 14:00 PM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
It amazes me how much people enjoy focusing on splitting hair, all so they can avoid evaluating the full scope of evidence... Well, setting up of impossible expectations doesn't do much for learning either.
In any event, thank you SkepticalScience.com for your stream of valuable information, stuff that we can actually learn from.
And thank you for your Reposting Policy, I'm honored to be able to Repost such an excellent article at my little effort.
http://whatsupwiththatwatts.blogspot.com/2014/03/gwpf-misleading-public_10.html
-
Albatross at 13:40 PM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Hi jwhite @31,
My gripe was not with your or the brevity of your post :) Rather Lewis's inexperience, background and who he chooses to associate with.
Thanks for notifying us about his CA post. Someone at SkS will have a look.
-
scaddenp at 13:30 PM on 11 March 20142014 SkS Weekly News Roundup #10B
A "wind the clock back" meter could only make sense if you were buying the power from the generator, not the supplier. This is essentially saying that you want the sell back to the retailer at the same price as you bought it, whereas the retailer is buying from wholesaler at much lower price. What business could do that? It is only realistic that you sell electricity back at the average price from other generators. Some of the buy-back prices offered in NZ look very generous to me. Really realistic would be that you only get paid for your electricity what the current wholemarket price is. Now sometimes, in a dry winter, that could be really high, but often when there isnt much solar then to generate.
While obviously the price difference includes profit for the retailers which could do with some scrutiny but it also includes the balancing act of giving consumers fixed prices while market price changes every 5 minutes, regulatory costs, line costs etc. There is a reluctance by government to lump those costs into a per-household "line charge" no matter how realistic because this amounts to a penalty for low-power users, stuck with high line charges and low usage costs. The current line charge is fraction of the real cost. There are going to have be a lot of solar generators harping about the difference before the government would reconsider the political cost of such a change.
Generating companies building peaking power plants are generally divorced from electricity retailers. They are building them because they see they can make money at times of high demand. Increased micro-scale solar generation doesnt really threaten this opportunity at the moment.
-
scaddenp at 13:06 PM on 11 March 20142014 SkS Weekly News Roundup #10B
[PS] Put the links in properly and there will be no complaints.
-
jwhite100 at 12:57 PM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
I apologize for my post being so brief, but I don't have the technical background to make an informed comment on Lewis's post. I was hoping someone here would be able to do that. That's why I brought it to your attention. I respect and very much appreciate this site.
-
william5331 at 12:39 PM on 11 March 20142014 SkS Weekly News Roundup #10B
Chriskoz@7
A good start would be net metering - ie. a single meter which turns backwards when your generation exceeds your power use. However, we must not try to deprive the power company of their profit. After all they maintain the grid which eliminates the need to have your own expensive batteries which must be replaced from time to time. A fair, transparent way would be to have a line charge but we must be careful here. The line charge should be the same for the user and the user/generator or the power company will gerimander the fee so that is still won't be worthwhile to install solar panels. Then the government could stop taxing solar in all sorts of ways. After the moderators comments, I don't want to 'advertize' my own blog but if you go to it under @6, there are a couple of blogs about how the German government, much lauded, taxes the small solar power installer 7 ways to sunday. (do you have this expression). The technology is adequate although it has some way to go and the price is right. It should be well worthwhile for everyone with, say, 2.5 or more daily peak hours, averaged through the year, to profitably put solar panels on the roof. There are benefits to the power companies too. Once we have smart meters which allow demand balancing rather than the present supply balancing, having a lot of solar, financed by the small customer, eliminates the need for the power company to invest in an expensive, seldom used power plant for peak shaving.
-
Albatross at 12:25 PM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
jwhite @28,
It is a pity that Lewis chooses to keep airing his view and opinions at locations (such as the GWPF and CA) that habitually attack climate scientists and routinely try and undermine climate science by distorting the facts and data. Where is Lewis on this thread? He is undoubtably aware of it, yet he is posting on sites run by extremists and fringe elements. Him doing so does not bode well for his judgement being unbiased.
His biases aside, I doubt very much that Lewis (a retired finacier) has the depth of knowledge, understanding and experience to speak to a complex issue such as this. Just as I would lack the same when speaking to models used to predict the financial markets-- you do not see climate scientists trying to argue that the economists and financeers methods are incorrect. But for some reason every contrarian out there feels that climate science is fair game and that they somehow know better. -
One Planet Only Forever at 12:10 PM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
I enjoyed reading the thorough presentation of information that Lewis, Crok, Currie, Annan, Henderson, McKitrick, Montford, and Loehle would have had access to. It was very informative.
If they were genuinely interested in improving the understanding of what is going on they would not be trying to get away with pushing out the glaringly inadequately investigated and justified information they have presented.
Any media that gave their 'report' an iota of attention without a little basic fact-checking needs to be on an "Unreliable Sources" list. An honest and balanced media report would make reference to the report and its authors and include evidence of the clear inadequacy of their report.
The gullibility of many in the current population, willing to accept whatever suits their deluded interest based on their experience immersed in the unsustainable and damaging mass-consumption socioeconomic systems, certainly makes attempts to best inform the general population about the unacceptability of how they want to 'enjoy their life' a battle, but it is worth fighting. As the unjustifiable claims become more glaringly incredulous, more and more people are will realize how easily impressed they had allowed themselves to become.
People addicted to the unsustainable and damaging artificial industrial chemical-filled mass-consumption socioeconomic system need to admit to the harmful nature of their addiction. Then the changes to a better sustainable life can begin.
-
Miguelito at 11:26 AM on 11 March 2014The Editor-in-Chief of Science Magazine is wrong to endorse Keystone XL
There is already about 650,000 barrels per day of rail-loading capacity for oil in western Canada. That's scheduled to grow to over 1,000,000 barrels per day by the end of this year. The additional cost of shipping by rail doesn't mean much either because the supply costs for Alberta bitumen are actually pretty competetive compared to world prices (contrary to what's typically perceived, Alberta bitumen is no longer a marginally economic source of hydrocarbons, but a relatively low cost one, competetive with alot of U.S. tight oi). In other words, making it ship by rail isn't going to change its economics very much.
So, that bitumen is going to get to market via pipe or rail as long as there is a market asking for it. Kill demand, either through a carbon tax or much stricter emissions regs, and you'll do a far better job at solving your carbon problem rather than picking on one particular source of supply.
I haven't even gotten into America's "carbon bomb" of its own, tight oil, whose resource potential might be up there with bitumen's.
-
jwhite100 at 09:52 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Lewis has a response to the Shindell paper here:
Moderator Response:[RH] This runs very close to the "no link only posts" rule. Please try to incluce some discussion of the issue when posting links.
-
scaddenp at 09:39 AM on 11 March 2014There is no consensus
Realist308 - this article is showing that the statement "that there is no scientific consensus" is false. You are entitled to believe that all those scientists could be wrong but I wonder whether you have same opinion on all those scientific theories on which there is a consensus? If your Dr tells you have x disease and the scientific consensus is that you need Y to save your life, do you go with the consensus or the crank who tells you it can fixed with magnets?
-
Russ R. at 09:22 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Kevin C,
Thanks, I'll give Shindel et al. a read.
Tom Curtis,
I tried the same type of spreadsheet as you. My results also depended on how much random variable I inserted.
I also looked at the 11 models in Kiehl's two charts. Not having the data, I estimated the values for CS, TF and AF as follows:
Model /CS (°C) /TF (W/m-2) /AF (W/m-2)
a /1.9 /2.04 /-0.6
b /2.1 /2 /-0.63
c /2 /1.7 /-0.7
d /2.5 /1.68 /-0.74
e /2.4 /1.6 /-1.15
f /3.7 /1.48 /-0.62
g /2.6 /1.24 /-1.26
h /2.7 /1.21 /-1.42
i /3.5 /1.2 /-1
j /4.6 /1.16 /-1.3
k /3.3 /0.8 /-1.15Between TF and 1/CS, ρ=0.78
Between TF and AF, ρ=0.76
Between 1/CS and AF, ρ=0.49
So, to answer my own question, the inverse correlation between CS and aerosol forcing isn't as strong, but it's likely not zero.
-
Tom Curtis at 09:04 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Russ R, I failed to include the B/C correlations in my response @24, and also made a small technical error on my spreadsheet. Having corrected both errors, however, I find one example with correlations of:
A/B: -0.62 B/C: 0.58 A/C: 0.01
The twenty one trial averages are:
A/B: -0.65 B/C: 0.33 A/C: 0.14
Consequently, I believe the point I made still stands.
Having said that, Kevin C's response is far more informative in this particular case.
-
Kevin C at 08:44 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Russ R: This big paper from Shindel et al would seem to be key.
They find that the correlation between aerosol forcing and ECS changes sign between CMIP3 and CMIP5 (also Andrews et al). However the CMIP5 models show no particular correlation between ECS and total forcing or effective aerosol forcing (which includes the indirect effect).
-
Tom Curtis at 07:54 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Russ R @ 13:
"Is it somehow mathematically possible that if A and B have a "strong negative correlation" and B and C have a "strong positive correlation" that A and C can have "no correlation"?"
I set up a spread sheet were A is a linear function plus a small random variable (Rand()*4), B is -A plus a smaller random variable (rand()*2), and C is a B plus a large random variable (rand()*16). Over a restricted range of values, I obtained in one instance correlations of A to B or -0.97, and of A to C of 0.06. Averaged across 21 trials, with a similarly restricted range of values the correlations were -0.59 for A to B, and 0.19 for A to C. So, in answer to your question - yes they can.
Of course, as the range of values increases, the correlations of A to B, and of A to C rapidly approach -1. In the first example given, over a range of 100 values the correlations were -1, and -0.99 respectively. Averaged over 21 trials, they were -0.99 and -0.97 respectively.
The key point here is that the range of values of climate sensitivity, and of aerosol forcing are small. Consequently this counterintuitive result is possible provided the variation the aerosol forcing is large (relative to that range), which it is.
I am not saying that this is the basis for the apparent divergence between Kheil (2007), and Schmidt. That may be due to specific differences between the specifications of the CMIP3 and CMIP5 experiments, or of the actual CMIP3 and CMIP5 models. But your intuitive argument is not automatically valid regardless of specific reasons.
-
nigelj at 06:43 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Of course its possible climate sensitivity may be towards the low side. It is also possible that a relatively small increase in temperature globally could be associated with much more extensive climate change than we have previously thought.
Weather patterns recently suggest this may be the case. Nobody seems to have considered this possibility.
-
Rob Painting at 04:35 AM on 11 March 20142014 SkS Weekly News Roundup #10B
Michael Whittemore - I need to get my butt into gear and finish the series of posts on deep ocean warming, but long story short; the stronger trade winds spin-up the subtropical ocean gyres - where surface water converges. Stronger surface convergence means stronger downward transport of heat down into the ocean interior because there is nowhere else for the water to go but down (taking heat from the surface with it).
When the trade winds undergo their typical multi-decadal weakening (the positive phase of the Interdecadal Pacific Oscillation) expect weaker deep ocean warming.
-
howardlee at 04:28 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
The paleoclimate report quoted above, with the exception of the PETM, deals with changes occurring within the slow feedback response time (deep oceans, weathering, etc). As such I believe they give lower sensitivity values than is applicable to our modern climate change. Carbon-belch events like the PETM, Permian, Triassic, Toarcian, even the Mid Miocene CRB/Monterey event, happen at timeframes faster than the slow feebacks can process them, causing CO2 to build up rapidly in the atmosphere and surface ocean. Warming in these events is much more severe due to the disequilibrium. Moreover the PETM timing in the above report is for a long-term event whereas one (albeit contoverial) paper recently put the initial CIE at 13 years. Modern climate change is not very comparable with glacial-interglacial slow changes, and much more comparable to the PETM, Triassic, Toarcian, and other rapid, massive carbon-belch events.
-
Rob Painting at 04:26 AM on 11 March 20142014 SkS Weekly Digest #10
John Hartz - In the opening paragraph you have incorrectly attributed John Mason as the author of the Science editor endorses Keystone XL post, rather than Andy Skuce.
Moderator Response:[JH] I have corrected the error. Thank you for bringing it to my attention.
-
witsend at 03:44 AM on 11 March 20142014 SkS Weekly Digest #10
I went to the UCSC Climate Conference last weekend where the panel of speakers was asked when activists would be able to quote scientists directly linking extreme weather to climate change, in order to inspire the public to respond to the threat of global warming. I think it was Benjamin Santer of LLNL who said that they were decades away in research before they would have the ability to do that and then Gavin Schmidt chimed in and added, "Scientists won't ever do that. Don't wait for that...if you're waiting for that, you are just WASTING YOUR TIME." So, when I saw your cartoon it reminded me that I made a comic for that! http://witsendnj.blogspot.com/2011/01/kitchen-table-comic.html
Moderator Response:[JH] Link activated.
-
Russ R. at 03:37 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
dana1981 @16,
Thank you for clarifying.
Kevin C @19
Has any similar analysis been done on the CMIP5 ensemble, to show the correlation (or lack thereof) between estimated ECS, and historical values for total anthropogenic forcing and aerosol forcing?
Tom Dayton @20,
Models are but one "line of evidence", as are observational studies. Currently, they point in different directions. Not hugely different... still within a likely range, but different enough to be cause for disagreement.
I expect that over time as the observational record grows and the models improve, that difference will resolve and a consensus will emerge. Until then, everyone will simply have to agree to disagree.
-
Tom Dayton at 02:20 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Russ R.: For example, read Box 12.2 (pp. 1110-1112). Figure 1 shows the probability density functions. And there is "On the other hand, AOGCMs show very good agreement with observed climatology with ECS values in the upper part of the 1.5°C to 4.5°C range." Later there is this sentence: "comparisons of perturbed-physics ensembles against the observed climate find that models with ECS values in the range 3°C to 4°C show the smallest errors for many fields (Section 9.7.3.3)."
-
Kevin C at 02:18 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
There are several points of confusion here:
1. The Kiehl paper was on the CMIP3 models.
2. Forcings are dignosed from the models, they are not an input to the models. The input to the models is the external influences on the system, e.g. anthropoenic changes to atmospheric composition.
3. Aerosol indirect effect, while it affects TOA energy balance, is technically a feedback rather than a forcing from the perspective of a GCM.
Put 2 and 3 together and it should be clear that sensitivity and radiative forcing can be correlated without training. I don't know to what extent that is the case in practice.
-
MA Rodger at 01:41 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
It is in examining GWPF Report 13 that Lewis & Crok's objections to the 'effective' TCR within GCMs can be fully assessed - within in the shorter GWPF Report 12, their explanation is cut down to incoherence.
The problems the IPCC GCMs exhibit, allegedly, is that they do not perform properly. The GCM 'effective' TCR values are far higher than even GCM 'actual' TCR values. This is what causes the GCMs to project their alarmingly high future temperatures (as opposed to the reassuringly low ones suggested by Lewis & Crok).The 'effective' TCR of course can be determined by using "the observational-TCR based formula" as derived by those clever analysts Lewis & Crok.
ΔT(2012-2100) = (ΔF(2012-2100) x OTCR)/3.71 + 0.15ºC
:where OTCR is derived (as described in GWPF Report Note 86) not just from ΔT(1951-2010) attributions but actual ΔT(1951-2010) as measured by real thermometers and these compared not just to ΔF(1951-2010) but also to ΔF calculated from dF/dt(1951-2010), both of which yield the exact same result (TCR=1.4ºC excluding a minor adjustment) which only goes to show how accurate this TCR derivation is!
Not only that, Lewis & Crok manage to manipulate this highly sophisticated and complex model to yield GCM 'effective' TCR not just for 2012-2100 but also for 1850-2000.
This is why Lewis & Crok find without even wielding a single error bar that, "in the case of climate sensitivity and TCR, arguably the most important parameters in the climate discussion" (and few would disagree with that), the IPCC AR5 "failed" to provide an "understanding (of) the scientific basis of risk of human-induced climate change." And if (unlike Lewis & Crok) you link to the source document laying out the role of the IPCC, you will find that Lewis & Crok are accusing IPCC WG1 of being in contravention of the Principles Governing IPCC Work. -
Russ R. at 01:36 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Tom Dayton,
You say:
"they are unwilling to make a point estimate of the value, but certainly are willing to make a range estimate"
Yes... and the range they give is "Equilibrium climate sensitivity is likely in the range 1.5°C to 4.5°C (high confidence), extremely unlikely less than 1°C (high confidence), and very unlikely greater than 6°C (medium confidence)."
So how exactly does Lewis & Crok's "best estimate for ECS of 1.6–2.0°C" contradict this?
You continue:
"And as is clear from other sentences, they judge the point value most likely is in the middle of that range than at either end."
Which other sentences? Citation please.
-
dana1981 at 01:33 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Russ @13 - the Schmidt quote is from a personal communication.
-
John Hartz at 01:14 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Climate sensitivity is also the topic of How much hotter is the planet going to get? by Michael LePage, New Scientist, Mar 9, 2014. LePage's article parallels Dana's OP with respect to recently published papers about climate sensititvity.
-
Tom Dayton at 01:09 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Russ R., you persist in your factually incorrect interpretation of the "no best estimate" quiote as meaning "we have no idea." That statement instead means they are unwilling to make a point estimate of the value, but certainly are willing to make a range estimate--the range they refer to in that same sentence as the "assessed lines of evidence and studies." And as is clear from other sentences, they judge the point value most likely is in the middle of that range than at either end.
-
Russ R. at 00:55 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
I agree that this "report" from the GWPF contains nothing new. It's just a reshuffle and redeal of existing literature. The only thing I find noteworthy is that it further reinforces the point that there is no scientific consensus on a best estimate for equilibrium climate sensitivity, which is entirely in agreement with the IPCC's statement in AR5 WG1 SPM: "No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies."
Tangentially, I'm not sure how to square Gavin Schmidt's statement above, with the findings in Keihl (2007).
Schmidt: "Climate model sensitivity to a doubling of atmospheric CO2 is intrinsic to the model itself and has nothing to do with what aerosol forcings are. In CMIP5 there is no correlation between aerosol forcing and sensitivity across the ensemble, so the implication that aerosol forcing affects the climate sensitivity in such 'forward' calculations is false."
Keihl (2007): "These results clearly illustrate a strong inverse correlation between total anthropogenic forcing used for the 20th century and the model’s climate sensitivity. Indicating that models with low climate sensitivity require a relatively higher total anthropogenic forcing than models with higher climate sensitivity....
These results explain to a large degree why models with such diverse climate sensitivities can all simulate the global anomaly in surface temperature. The magnitude of applied anthropogenic total forcing compensates for the model sensitivity...
What is the major reason for the large uncertainty in total anthropogenic forcing? Figure 2 shows the correlation between total anthropogenic forcing and forcing due to tropospheric aerosols. There is a strong positive correlation between these two quantities with a near 3-fold range in the magnitude of aerosol forcing applied over the 20th century."
- Is it somehow mathematically possible that if A and B have a "strong negative correlation" and B and C have a "strong positive correlation" that A and C can have "no correlation"?
- Are the latest generation of GCMs somehow entirely different, rendering Keihl's observations out-of-date? Has Schmidt actually back-tested the CMIP5 ensemble in the same way that Keihl did with earlier models and found no correlation?
Also, could someone please link to a source for Gavin Schmidt's quotation? I couldn't find it on realclimate or anywhere else, except for here and in Dana's column in the Guardian (which linked back to here).
-
StBarnabas at 00:55 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
@Tom Curtis
if you email me at sean.danaher@unn.ac.uk I can forward you a copy of the Leohle paper
-
Albatross at 00:38 AM on 11 March 2014GWPF optimism on climate sensitivity is ill-founded
Tom @4,
Thank you for the info on the three Lewis papers.
We at SkS are aware of the new Loehle paper, how shall I say this...? There are several critical issues that undermine the premise of his paper and his results. I will leave it at that for now.
Prev 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 Next
