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Eclectic at 17:25 PM on 15 July 2017Models are unreliable
Correction : that should be addressed to NorrisM @1063.
My apologies for that typo.
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chriskoz at 17:24 PM on 15 July 2017Study: On climate change and elsewhere, politicians more conservative than citizens
I don't think increased lobbying by voters will change politician's mind.
Just like they deny science, they also deny reality in broader sense, the same mechanism of cognitive bias aply here. T-man is a prime example.
Rather than increased citizen's lobbying, other measures, that would remove the incentives for cognitive bias, will be more effective: e.g. to start with, ban all political donations by industries (FF industry in particular) and over small limit. Then they would not be as encumbered by e.g. Koch bros as they are right now.
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Eclectic at 17:20 PM on 15 July 2017Models are unreliable
NorrisM @1061 , several points :-
1. Yes, you are beyond even the most extreme naivety, if you feel there's a chance that the political extremists [= Republicans, in this case] would come to any "acceptance" of what the climate science is telling us. And I'm sure that you, as a man of the world, are aware of the situation. It doesn't matter how many hearings occur, at ever higher levels of review and appeal, all the way up to the Supreme Court or beyond . . . . . the extremists will reject authoritative judgment (even if it were issued by the Archangel Gabriel).
2. The Global Warming issue has already already been "Red-Teamed and Blue-Teamed" extensively, for many years — and the result is as you know, a unanimous decision by the only court truly competent to make the judgment (i.e. by the scientists who have the technical knowledge to make the properly-informed decision). Yes, not quite strictly unanimous : there is a minuscule group of "dissenter" climate scientists [ well under 1% ] but their decisions are incompetent owing to the incoherent and mutually contradictory assertions they make. (And a realistic cynic would regard these "few" as composed of crackpots and/or shills for vested interests).
3. The politicians who reject & deny the plain scientific truth, will only change their viewpoint if it seems imminent that they will be voted out by a "fed-up" public — or if their major donors die off or themselves succumb to public pressure (e.g. to shareholder revolt). It is the long-running propaganda campaign of denial, which is the actual influencer or "hamperer" of public opinion : and not any judicial decision or series of judicial decisions.
4. NorrisM, let us be realistic : the question of virtuosity of "models" is unnecessary to the scientific case. The real physical world has already given us the decision, by means of obvious and incontrovertible evidence — sea levels have risen and are rising ever faster; planetary temperature has already risen 1 degreeC above the previous [downward] trend; glaciers and polar ice and permafrost are disappearing at a rapid & increasing rate; the oceans have warmed & acidified; plants and animals have changed their traditional pattern of activity.
Crackpots & shills try to delude themselves and deceive us with graphs which are downright economical with the truth [to use that ironically polite phrase!!]. But in summary :- the world is clearly rising significantly higher in temperature, and with no sign of slowing down any time soon — so to that extent "models" are unnecessary for responsible policymakers (and for us ordinary citizens, too).
Reckless foolhardiness & negligence are the traits of the "deniers".
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NorrisM at 15:20 PM on 15 July 2017Models are unreliable
Thanks everyone above.
Nigelj, I have to admit that 1054-1059 are challenging for a lawyer. I have not had time to go to realclimate.org but I will after we return from holidays. On our sailboat and hoping for wind but I have to admit, I do turn the diesel engine on when there is no wind!
To me the issue of how close the models match observations over whatever necessary period (20 years?) is critical. The "other side" says that there are large discrepancies (I believe that is what they say). If anything, a Red Team Blue Team approach would be the opportunity to show the other side what the models can and cannot do over specified periods of time and how accurate they are. As I noted elsewhere, Santer and Held had the chance to make this point at the APS panel and now have Koonin questioning the models because they did not adequately defend them.
My simplistic understanding of the scientific method is that one comes up with a theory and tests it to see if it is borne out by the tests. Or the model makes predictions and one looks back to see if the models were correct.
If the models cannot show that they are accurate over a 10 year period, then it does get problematic because how are public officials expected to commit massive amounts of funds until the models have shown that it is reasonable to assume they are right on, for example, a 3C rise by 2100 assuming that it is "business as usual"? When I use "predict", I mean a model projection which assumes that no mitigation is taken.
One last point before I head off. I do not think we can rely on "hind casting" to prove that the models can closely match reality because there are too many "fudge" factors used to make the models "fit" the actual history. There is no way of knowing if the same fudge factors work for the future. This is not original, I know. I think this is Freeman Dyson's comment at the beginning of this thread.
i will certainly spend more time on this when I get back. Perhaps by then we will have heard what the Trump administration has decided to do. If all we get is a TV debate as suggested by Scott Pruitt then all we will get is a gong show.
I truly think that a scientific debate along the lines of a legal hearing with both sides going at each other with an independent panel coming to a decision (with dissenting opinions) would be the best way to achieve some form of acceptance by the Republican party. I know this sounds naive but I have to admit I would like to see it!
Moderator: Sorry, just a little "off topic" at the last. Sometimes it does not make sense to fully "stream" these thoughts.
I am very much still a "fence sitter" on this issue because it is so technical and you have intelligent human beings on both sides of this debate saying different things. It is very frustrating. You would think that everyone could at least agree on the facts. Perhaps the Red Team Blue Team traditional approach could achieve some agreement on at least how far apart the models are from observations. That is why I so much trust our adversarial system of justice in Canada and the US compared to the European system. Let each side go at it and have an independent judge or judges render their decision AND provide their reasons for their decision. If there is disagreement amongst the panel, then dissenting opinions are also given.
Moderator Response:[DB] "If the models cannot show that they are accurate over a 10 year period"
As Tom Dayton notes, you continue to ignore the explanation he gave you even earlier. You also continue to not investigate the links you were given. You instead resort to sloganeering (repeating claims already invalidated). In a judicial trial, a judge would warn you for this behaviour. In this venue, there is a similar reproach.
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Eclectic at 11:34 AM on 15 July 2017Water vapor is the most powerful greenhouse gas
Thanks DB. I particularly like your first chart, which presents a "balanced" argument ;-) ..... though at the most elementary level [suited to my mind!!] it doesn't make the important distinction between "feedback" and "forcing".
JeffDylan @277 , we arrive at the frozen world scenario (discussed earlier) because there is a huge difference between CO2 and H2O as GreenHouse gasses.
At first glance , you might think there is not much difference — because under present-day Earth conditions, CO2 contributes [IIRC] roughly 30 watts/squ.meter of GreenHouse warming and H2O (vapor) roughly 70 watts/squ.meter of GH warming. But there is a huge difference in negative feedback once you "perturb" things toward lower levels of GH gasses. The essential cause of the difference is that at habitable temperatures, H2O transforms between ice / water / vapor over a very narrow temperature range (while CO2 remains as a gas, and exerting its usual GH effect).
How this difference works out "so differently" — is through the albedo effect. Currently the Earth has an albedo of about 0.3 , so roughly 30% of the sun's heat (predominantly as light) is reflected away, and 70% is absorbed by the planetary "surface". Yet snow/ice has an albedo of about 0.9 — so as a greater percentage of the planet gets covered in ice, there's a vast reduction in absorption of the sun's heat. It is a very strong feedback, since cooler air loses H2O vapor which is precipitated as snow and frost (and more extensive sea-ice) and more ice leads to even colder conditions. And so it goes. And hence the (hypothetical) fully frozen world, which stays frozen [if without CO2].
You can see a more graduated (and fortunately limited!!) effect occurring in the real planet Earth. So the scientists are well-justified in calling CO2 the "control knob" and describing H2O vapor as the tail on the dog [metaphorically speaking].
Yes, the dog's H2O tail is bigger than the CO2 dog [at present temperatures] -— but it is the dog which controls where it goes!!
And hence the emphasis on the vital importance of reducing atmospheric CO2.
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Daniel Bailey at 09:39 AM on 15 July 2017Water vapor is the most powerful greenhouse gas
"If we take the earth and atmosphere as is, and made every atmospheric CO2 molecule vanish, we would certainly lose the greenhouse effect contribution from CO2, but remember that H2O is the stronger and more abundant greenhouse gas. Therefore, we would expect a small reduction in greenhouse heating possibly causing temperatures to drop by a few degrees C, but not at all like the "frozen world" you describe."
Real scientists have examined exactly that. FYI, Water vapor is a condensible GHG. As such, and by definition, it cannot be a driver of temperature changes but can only serve as a feedback to them.
Carbon dioxide, on the other hand, is the most important temperature control knob on the planetary thermostat.
"Ample physical evidence shows that carbon dioxide (CO2) is the single most important climate-relevant greenhouse gas in Earth's atmosphere. This is because CO2, like ozone, N2O, CH4, and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can, and does.
Non-condensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect.
Without the radiative forcing supplied by CO2 and the other non-condensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state."
"The climate system of the Earth is endowed with a moderately strong greenhouse effect that is characterized by non-condensing greenhouse gases (GHGs) that provide the core radiative forcing. Of these, the most important is atmospheric CO2. There is a strong feedback contribution to the greenhouse effect by water vapor and clouds that is unique in the solar system, exceeding the core radiative forcing due to the non-condensing GHGs by a factor of three. The significance of the non-condensing GHGs is that once they have been injected into the atmosphere, they remain there virtually indefinitely because they do not condense and precipitate from the atmosphere, their chemical removal time ranging from decades to millennia. Water vapor and clouds have only a short lifespan, with their distribution determined by the locally prevailing meteorological conditions, subject to Clausius-Clapeyron constraint.
Although solar irradiance is the ultimate energy source that powers the terrestrial greenhouse effect, there has been no discernible long-term trend in solar irradiance since precise monitoring began in the late 1970s. This leaves atmospheric CO2 as the effective control knob driving the current global warming trend.
Over geologic time scales, volcanoes are the principal source of atmospheric CO2, and the weathering of rocks is the principal sink, with the biosphere participating as both a source and a sink. The problem at hand is that human industrial activity is causing atmospheric CO2 to increase by 2 ppm/yr, whereas the interglacial rate has been 0.005 ppm/yr. This is a geologically unprecedented rate to turn the CO2 climate control knob. This is causing the global warming that threatens the global environment."
And:"If there had been no increase in the amounts of non-condensable greenhouse gases, the amount of water vapor in the atmosphere would not have changed with all other variables remaining the same.
The addition of the non-condensable gases causes the temperature to increase and this leads to an increase in water vapor that further increases the temperature.
This is an example of a positive feedback effect. The warming due to increasing non-condensable gases causes more water vapor to enter the atmosphere, which adds to the effect of the non-condensables."
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JeffDylan at 09:10 AM on 15 July 2017Water vapor is the most powerful greenhouse gas
Eclectic — I'm not sure I understand how we arrive at the frozen world scenerio you described in 268. If we take the earth and atmosphere as is, and made every atmospheric CO2 molecule vanish, we would certainly lose the greenhouse effect contribution from CO2, but remember that H2O is the stronger and more abundant greenhouse gas. Therefore, we would expect a small reduction in greenhouse heating possibly causing temperatures to drop by a few degrees C, but not at all like the "frozen world" you describe.
Remember that the earth, atmosphere, and solar radiation as they are today must share an energy balance relation. That is, whatever energy the earth and atmosphere absorb from the solar radiation must be re-radiated from the earth and atmosphere, at least in the long term. Since CO2 has only a minor impact on the greenhouse effect, I would not expect the temperatures after CO2 removal to be much different from what they are now in order to maintain energy balance.
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bjchip at 08:20 AM on 15 July 2017Study: On climate change and elsewhere, politicians more conservative than citizens
Darn it... I keep forgetting the link thing.
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bjchip at 08:19 AM on 15 July 2017Study: On climate change and elsewhere, politicians more conservative than citizens
So maybe liberals vote but their votes aren't counted?
Maybe they don't pay attention in the local elections that ultimately determine the lines drawn for the larger issues?
http://athensforeveryone.com/gerrymandering-fairness-and-you/
Maybe there is a reason we are governed by a minority?
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nigelj at 08:01 AM on 15 July 2017Planet Hacks: Food
John Wise @6, I do accept there seems some inconsistency in the two links on the total emissions from agriculture. The second is most accurate. If you want a more authoritative analysis of fundamental sources of emissions try the American EPA as below. They discuss all sources and agriculture is 24% similar to my second link:
www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data#Sector
However your question related to carbon footprints of different types of foods, and I responded to that. As you can see two different sources gave similar results, which gives some credibility to the numbers. I have no reason to doubt the basic percentage differences between the foods, and you haven't given me any. You have basically changed the subject and shifted the goal posts.
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nigelj at 07:22 AM on 15 July 2017Study: On climate change and elsewhere, politicians more conservative than citizens
"American politicians perceive their constituents’ positions as more conservative than they are."
This comes as no surprise to me. Perhaps politicians just hear what they want to hear.
Polls by organisations like Pew consistently show the majority of Americans want action on climate change, in stark contrast to the views of Congress.
As you say perhaps conservatives lobby more. Here is another possibility that may explain part of this issues. I listen to talkback radio sometimes (not hugely, it can get a bit mind numbing at times, the ignorance is astounding) but one thing comes across clearly. It's the conservative leaning callers that dominate, and are the loudest and most direct and blunt in their views. Liberal leaning callers are fewer in number, and tend to be more laid back, nuanced and complex in their views. It creates an impression that conservative views are more numerous, when they clearly actually aren't.
This conservative dominance is possibly because liberals promote tolerance as a key value, so dont want to be too blunt. They end up holding back just a little too much at times.
I find both conservative and liberal views interesting and am not saying one side is always right, because that's just not the case in my view. But the way views are put has a difference.
However for some reason liberals and conservatives seem equally loud in internet forums, but politicians still probably look a lot at traditional media like radio, given their age group.
The views of people are complex and confused as well and this is what politicians are listening to. The Economist.com July edition did an interesting, excellent and relevant article called America Divided. It would be on their website if you are a subscriber and you can get a few articles for free. Briefly they interviewed people living in small town america and discussed political views, occupations, and voting habits etc.
They identified some partisan divisions between conservative / liberal and occupational groups particularly. They identified partisan divisions between republican and democrat, but not as large as anticipated. They found many people were not too clear on what the parties even stood for, and voting was often out of habit, peer group leanings, and personalities rather than policies.
Some voted for Trump because he "spoke like them" or said he cared, even although they admitted his policies didn't make a lot of sense. However democrat and liberal leaning people tended to look a little more at policies than personality. Personally I think its policies that count for most.
You therefore have a very complex, confused voter base feeding information back to elected representatives. With so much poor quality understaanding of policies the end result is not going to be good. In such an environment it will also be the loud groups with vested business interests that dominate, and get through to politicians and articlulate views most cogently, for good or bad.
The other obvious dynamic is politiicans are funded by various groups including fossil fuel lobbies, and are therefore probably susceptible to the wishes of those groups. But that's another separate issue.
I agree if people want Congress to reflect their views they need to engage politicians directly. This overcomes many issues. People also need to state their views more firmly. Being tolerant and open minded should not have to mean being too reticent or wooly thinking or holding back.
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John Wise at 06:55 AM on 15 July 2017Planet Hacks: Food
nigelj
Thanks for the links. They contain similar information to others I have read. They are all over the place. The first(greeneatz) suggests that as much as 50% of emissions are due to agriculture,mainly from livestock. The second(U. of Michigan) states in the text that over 20% are from agriculture. Then,in the graph further in the MIchigan article,it breaks down U.S. emissions as follows: transportation 27%,energy 32%,other fuel 11%,manufacturing 12%,fugitive emissions 4%,industrial processes 5%,waste 2%,and agriculture 8%.
So,we have 8% to 50% of emissions from agriculture? I realize that the other categories include transportation,food processing etc.,but 50% seems pretty high.
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BBHY at 06:50 AM on 15 July 2017Study: On climate change and elsewhere, politicians more conservative than citizens
I saw an article on Grist yesterday about the actions people can take on climate change, but voting wasn't included.
I think voting may be the most important step people can take. Changing your lightbulbs and not bothering to vote against climate denier politicians is a failed strategy.
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BBHY at 06:47 AM on 15 July 2017Study: On climate change and elsewhere, politicians more conservative than citizens
Many liberals don't vote, often because they don't have candidates that represent their values. In many districts, the Dems even allow the R candidate to run unchallenged.
This is wrong. If a football coach said the team was only going to try to win the easiest games, he would be fired immediately.
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nigelj at 06:25 AM on 15 July 2017Conservatives are again denying the very existence of global warming
Doug_C, yes well said. The manufacturers of tobacco and oil / coal etc have a lot in common, including huge vested interests, and a historical tendency to deny the science, and blatantly misslead people. Both groups knew about the problem, and knew it was real, much earlier than they admitted.The book "Merchants of Doubt" documents some of this.
I have also often wondered if the users fossil fuel use also have a sort of addiction, or at least an ingrained habit and of course that includes many of us. In my view theres no real hard line defining what substances can form addictions, or when an addiction becomes a habit. I think it's all just matter of degree to some extent, and more a question of whether the addiction is causing more harm than good.
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nigelj at 06:11 AM on 15 July 2017Planet Hacks: Food
John Wise @4
Here is a quick comparison of carbon footprint of meat versus various lentils and vegetables. I assume its full life cycle:
www.greeneatz.com/foods-carbon-footprint.html
Here is a more detailed comparison and explanation:
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carn at 01:33 AM on 15 July 2017It's too hard
@ Eclectic
"Yes Carn, that outcome is quite understandable — if we deliberately do nothing more than sit on our bums."
No, this is not only a "function" of our efforts, but also depend upon laws of nature and what they allow for and what they do not allow for. Science and research is not some 'work hard and you get what you want'; its 'work hard and maybe nature is nice, maybe it isn't; and maybe one day it falls into your lap without effort; and maybe you will achieve it never'.
"Please show some Can-Do attitude"
Its just the "Can-Do attitude" by some ecos that gives me the chills; they claim that something is possible via R&D at some date; then laws are passed towards that; and nobody ever caring whether it is realistic or not; leading to all kinds of problems and maybe not even helping in regard to GW.
"and express your own ideas of how best to tackle the AGW problem"
Change rules for building permits, safety regulations and police laws such, that nuclear power can be ramped up by at least 50% per decade. Especially weaken the insanely low concentration limits for radiation and the insane differntiation between "natural" and "artificial" radiation. Cut all funding for all eco groups having the slightest problem with that and use all legally avaible means to utterly bankrupt, destroy, dissolve such groups.
Cut subsidies for solar power and electric cars to such an extent that devlopment continues but building lots of ecologically inefficient solar power plants/cars is avoided.
Subsidies for wind power can to some extent remain (wind power is lot more ecologically efficient than solar).
Also change building permit rules, ecological protection laws, etc. that the scenario "there is enough water flow for a hydro power plant" results in 75%+ of all cases within 15 years into "there is a hydro power plant"; hydro power is the most ecologically efficient stuff out there and can serve as near perfect storage for compensating changing wind power output. If any eco cries about some poor endangered species living in the area effected by a dam, directly kill some of the creeps so the ecos understand no one cares about animals (which we do not need), since the issue is saving human lives.
Develop the technology for using nuclear power plants to create hydrogen, so nuclear plants can operate either in elcetric production more, when wind output is low, or in hydrogen production mode, when output is high.
But it seems to me, that many people will disagree with my suggestions; some for good reasons, but many due to simply not thinking but letting their emotions think.
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John Wise at 01:05 AM on 15 July 2017Planet Hacks: Food
Can anyone direct me to a study showing the full lifecycle carbon footprint of ruminant meat/dairy production on pasture vs. plant protein production such as beans or lentils?
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Doug_C at 01:03 AM on 15 July 2017Conservatives are again denying the very existence of global warming
I live in BC, the forcast today is sunny with smoke from the wildfires that are all across this Canadian province, it has been this way for a week and is forecast for days to come.
NASA is detecting the smoke from the worst wildfires in Siberia in 10,000 years.
There are so many indicators like this that the climate in many places has been altered significantly already with more to come that denying human forced climate change is purely an exercise in marketing, not even marginal science. People make a living selling fossil fuels indirectly by denying the negative impacts in almost exactly the same way they sold so many cigarettes for so long long by concealing how dangerous they are.
Big tobacco and climate change denial
It's basically lying for a living in the interests of a product that is eventually going to kill off not just billions of people if left un-mitigated, it will take out a huge swack of the entire biosphere just like any carbon dioxide driven extinction event in the past. The tobacco industry used denial of the science to "recruit" replacement smokers for the ones their products killed.
We don't have a replacement Earth.
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Eclectic at 17:00 PM on 14 July 2017Water vapor is the most powerful greenhouse gas
JeffDylan @273 , I hope you found TD's and Scaddenp's posts helpful.
The hypothetical fully frozen world is locked in stable equilibrium (since it lacks CO2 in its atmosphere) but of course it is only an illustrative example of how CO2 or H2O greenhouse effect works.
The real physical world is the one we are interested in. And in the real world, it is largely CO2 which works as the "control knob". Real-world perturbations (e.g. your "forest fires, volcanoes, lightning, or even a solar flare") are brief and relatively small, compared with the decades/centuries-long cumulative effects of CO2 planetwide.
You might also be interested to look at the (intermediate) "CO2 Lags Temperature" [Climate Myth Number 12, via the Home Page] where the Milankovitch cycles are mentioned. The biggest take-home message there, is that subtle alterations in albedo (Northern Hemisphere ice cover & vegetation changes) connected with summer/winter axial tilt, being enormously amplified in effect by consequent outgassing (or the opposite) of CO2 from the oceans. Hence the lag effect, mentioned.
Climate science is like a 1000-piece jigsaw puzzle where all of the pieces fit together nicely to produce a portrait. Even with a piece or two missing, the portrait still presents a clear and unmistakable picture (and does not produce "alternative" pictures). JeffDylan, I sense you feel that [so to speak] one of the pieces is upside down or in the wrong place. If that is so, then please clarify your thoughts on the matter (but I strongly suspect the overall picture will remain the same — and that your unease stems from a semantics problem, not a physical-reality problem).
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Tom Dayton at 15:03 PM on 14 July 2017Water vapor is the most powerful greenhouse gas
JeffDylan, if the instability of the sensitivity you described existed, it would exist for all configurations of the Earth, not just frozen Earths. Think about it--all of them. Empirically that simply is not the case. Please read the "runaway" post I pointed you to.
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scaddenp at 14:57 PM on 14 July 2017Water vapor is the most powerful greenhouse gas
As per Tom Dayton - "unstable" implies feedback with gain > 1.0. Maybe there is a some configuration with this level of unstability but I am unaware of any evidence from observation or models for such a strong gain. Certainly in the modern climate, water feedback gain is small (0.3-0.4 from memory).
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JeffDylan at 14:35 PM on 14 July 2017Water vapor is the most powerful greenhouse gas
By "perturbation", I mean any event that releases heat into the atmosphere. It could be forest fires, volcanoes, lightning, or even a solar flare. The purpose of part (b) of my posting @270 is to show that the "frozen world" scenerio described by Eclectic @268 is not stable even though it is an equilibrium, and to analyze stability of a system in equilibrium, we ask the general question "Will some small deviation (or perturbation) in the system from equilibrium grow?". In this case, the answer is "yes". As I argued in 270, a tiny amount of heat applied to the ice leads to big changes in the greenhouse heating which means the system is unstable. Therefore, we really can't use this frozen world scenerio to conclude anything.
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nigelj at 13:40 PM on 14 July 2017Planet Hacks: Food
Just adding to OPOF's list of cultural reasons for meat eating. According to this psychologist American meat eating is related to validating and celebrating manhood.
www.nbcnews.com/id/49920136/ns/health/t/why-real-men-eat-meat-it-makes-them-feel-manly/#.WWg4-4SGPIU
In my view it probably goes right back to stone age men killing wooly mammoths etc, and roasting them over the fire. It may have become a cultural meme / memory. This probably explains why we love barbecues.
You have other cultural meat issues. Sharks and rhino's are also killed for perceived therapeutic properties of the fins, and horns, despite a total lack of supporting scientific evidence. Whale meat remains a cultural delicacy in certain countries, despite dwindling numbers of whales. While cultural differences are worthy of respect, hunting species to extinction or very low numbers raises its own series of concerns.
Soils and plants have potential as carbon sinks if properly managed, as is well known. Intensive cattle farming and / or poorly managed farming can strip grasslands bare or reduce grass root bundles, and thus reduce potential carbon stores.
en.wikipedia.org/wiki/Carbon_sink
All things taken together suggest high meat consumption has a range of problems.
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Tom Dayton at 12:41 PM on 14 July 2017Water vapor is the most powerful greenhouse gas
JeffDylan: Positive feedback whose gain is less than one converges (peters out). The smaller the gain, the faster it converges. See the post about runaway (though I understand you did not claim it would run away). Note there are Basic, Intermediate, and Advanced tabbed panes.
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Eclectic at 12:28 PM on 14 July 2017Water vapor is the most powerful greenhouse gas
JeffDylan @270 ,
we should await better brains than mine, to give some quantification to the scenario you have proposed!!
As I picture it, a minor perturbation (in the warming direction) would only release a tiny amount of H2O vapor, which would promptly fall back as snow & frost — i.e. it would not meet the threshold to achieve current ambient temperatures (to maintain enough vapor to give positive feedback).
I am not sure of what cause of perturbation you were thinking about. If it was of ("Milankovitch") alterations of planetary tilt or orbital shape, then these would produce only very tiny changes in solar heat flow into the planet. Volcanoes? — they would produce both a "sooty" coating to surface ice [positive] and atmospheric reflective particles/aerosols [negative] : but their real cumulative warming effect would come from the CO2 emitted. Which brings our discussion back full circle!
Without CO2, it is difficult for a fully frozen world to "escape".
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JeffDylan at 11:46 AM on 14 July 2017Water vapor is the most powerful greenhouse gas
Eclectic @268 — Thanks for your response. Understand however that the "answers" I get about the dominant greenhouse gas are generally incomplete or don't make sense at some point.
I did some pondering on your thought experiment, and I believe your prediction in part (a) is correct. Since energy balance is maintained in the long term and the supply of liquid H2O for water vapor is virtually limitless, it makes sense that the earth would tend to return to that state if the atmospheric H2O vapor is somehow removed.
In part (b), however, I believe your prediction is erroneous. The "frozen world" you mention is an unstable equibrium. Although there is no greenhouse effect due to the fact that the CO2 was removed and H2O exists as a solid instead a gas, any minor perturbation of the system that causes some heating will drive H2O molecules from the ice to the atmosphere, thereby causing greenhouse heating which in turn causes more H2O molecules to leave the ice and enter the atmosphere, which causes more greenhouse heating. In this manner, the H2O content of the atmosphere increases until a new equilibrium/energy balance state is obtained. This new state may be somewhat cooler than the old state that included CO2, but it certainly would not be a long-term frozen world.
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Eclectic at 10:44 AM on 14 July 2017Water vapor is the most powerful greenhouse gas
Yes, my apologies TD.
I spoke with clumsy brevity, and was thinking of the H2O's interchange between vaporous and droplet form while remaining in the atmosphere.
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Bob Loblaw at 10:27 AM on 14 July 2017Models are unreliable
Also following along the question of removing El NIno effects from the observational record, a simper appraoch is to look at only the years with El Nino, only the years with La Nina, and the remaining "neutral" years as different data sets. Examining the trend in each set individually will help separate the effects in a much simpler manner than the multiple regression or modelling techniques. The simplicity may make it easier to understand.
This has been done by John Nielsen-Gammon, and SkS posted on this in this discussion:
https://skepticalscience.com/john-nielsen-gammon-commentson-on-continued-global-warming.html
Short story: all three sets show basically the same trend.
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scaddenp at 08:48 AM on 14 July 2017Climate scientists just debunked deniers' favorite argument
Mike, perhaps you could point us to a statement in IPCC science report or published paper which you think does reflect the necessary humility?
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nigelj at 08:16 AM on 14 July 2017Models are unreliable
My two cents worth. I'm not a scientist, and not a lawyer, but I have done some stage 1 introductory level university maths, chemistry, physical geography, in the 1980's.
The comments 1054 - 1059 above on models are of course perfectly correct, but would be hard for a lawyer or total lay person to understand.
I would simplify or maybe summarise comments by saying models can predict long term temperature trends, and endpoints, because greenhouse gases and basic, underlying long term solar changes can be quantified as a long term trend. Models cannot predict every wiggle along the way, because ocean processes are slightly random in their timing. These wiggles might be a couple of years or up to ten years, but they don't alter the basic long term trend or track.
This is how I have explained things to denialists. If I'm wrong please tell me.
The pause was significant, but by the time it was properly measured, it was not outside of what models predict could happen.The "pause" looks about 8 years maximum in the nasa giss graph. Models have error bars partly to allow for this short term, random, natural variation.
If you look at the model / real world data comparisons on realclimate.org the models are predicting temperatures over the last 30 years pretty well.
Temperatures are slightly 'under' but not by much, and are certainly within error bars.
The more useful question is to ask why are models still slightly over estimating temperatures. I have read a theory that oceans are delaying warming a little.
Anyway if you look at the realclimate graph, it obviously wouldn't take much for temperatures to jump towards the very top of the error bar.
The bottom line is it seems absurd to me to claim in 2017 that models are way off, or anything like that. Therefore scientists claiming this are grand standing to make inflammatory statements. I dont think that really helps, as it gets picked up by the media.
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scaddenp at 07:39 AM on 14 July 2017Climate scientists just debunked deniers' favorite argument
Mike - I have responded to your comment on a more appropriate thread.
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scaddenp at 07:37 AM on 14 July 2017Models are unreliable
Responding to comment by Mike from here
Further to that - when modellers run one of projections for what humans will do (the RCPs which are about emissions, aerosols), they also have to put in what they think natural forcings will be. (Sun, volcanoes). These are not predictable. If you didnt put in some volcanic eruptions, then the models would always run to hot. However, modellers cannot actually predict when, where, or how big an actual eruption will be - so you put representative volcanic aerosols based on average past history, and vary that with runs. Solar is also hard to tie down precisely.
So if your interest is how well a particular model predicted climate 10 years ago, it is better to rerun the identical code but with actual forcings not the what was projected at the time. This will tell you how well the model will predict climate as opposed to how well modellers predicted forcings. Unless you are pseudoskeptic of course - if so then any distortion that backs your ideologically-based prejudices is just fine, by ideology beats reality, right?
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wili at 06:48 AM on 14 July 20172017 SkS Weekly Climate Change & Global Warming Digest #26
Oops, I see that you already addressed this in the comments section of the more recent WD. I still think that it is an important discussion for SkS to be in on, but it's obviously up to you all.
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wili at 05:22 AM on 14 July 20172017 SkS Weekly Climate Change & Global Warming Digest #26
For the next weekly digest? :
NYMagazine: "...What CC could wreak..."
Much discussed at various places online and on twitter... -
Tom Dayton at 02:39 AM on 14 July 2017Climate scientists just debunked deniers' favorite argument
Mike Evershed: GoogleMaps is a computer model of traffic. It "predicts" when I will arrive at my office, given my home departure time. I run that model multiple times, each time with a different input of my departure time (a different "scenario"), and each such run "predicts" the resulting arrival time. GoogleMaps does not predict when I will depart, so it does not predict when I will arrive.
GoogleMaps can be "wrong" about my arrival time if I input the wrong departure time. GCMs can be "wrong" about the climate if I input the wrong forcings. Such "wrong" outputs do not in any way reflect poorly on GoogleMaps or GCMs. To help keep that distinction clear, scientists use the term "projection" for what GCMs output, as a more concise term than "prediction given a particular set of input assumed forcings."
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Tom Dayton at 02:31 AM on 14 July 2017Climate scientists just debunked deniers' favorite argument
Mike Evershed: The models are not used to make "predictions," they are used to make "projections." Whereas in typical English those terms might be synonyms, in technical climatological language "prediction" means asserting both that a set of specific values of climate forcings will occur, and that the climate will respond in a particular way. Climatologists rarely use "prediction," because rarely do they assert that a particular set of values of forcings will occur.
Climatologists usually use "projection," because they make merely a working assumption about the values of the forcings, which they give as inputs to climate models. The models themselves do not "contain" those forcing values, but merely respond to them. For example, the climate models do not make predictions about the amount of energy the Sun will deliver to the Earth's top of the atmosphere. The climate models instead "predict" the Earth's climatological response to whatever solar energy is input to the models.
For climate models to produce those estimates, they must be given those forcings as inputs. Each set of such forcing inputs is called a "scenario" or a "Representative Concentration Pathway." Models' accuracies properly can be judged only by comparing their projected responses to the forcing scenarios that actually happened. In the absence of a time machine, that must be done after the fact. "Hindcasts" of the models are exactly that: "projections" using the values of the forcings that actually happened, up to the most recent year for which the forcings are known. When models are run for years in the future, scientists input to them one or multiple scenarios as what-ifs.
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Mike Evershed at 01:34 AM on 14 July 2017Climate scientists just debunked deniers' favorite argument
As I understand it the authors of the recent paper in Nature Geoscience said that: "We conclude that model overestimation of tropospheric warming in the early twenty-first century is partly due to systematic deficiencies in some of the post-2000 external forcings used in the model simulations". As neither a believer or a denier, I think the logical view to take is that the model predictions were indeed wrong and due to wrong assumptions. I leave others to judge whether the wrong assumptions reflect shortcomings in our understanding of how the climate works. But I would plead for more humility on all sides in this debate.
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Eclectic at 01:16 AM on 14 July 2017Water vapor is the most powerful greenhouse gas
JeffDylan @267 , as the moderator has indicated, you seem to have misunderstood the rebuttal presented here. Permit me to expand the discussion :-
The authors pointed out that H2O vapor has a larger greenhouse effect (than CO2 does) at current ambient temperatures of the planet. And you agree with that. However, when the authors pointed out the "fragility" [if I may call it that] of H2O levels existing in vaporous & cloud-droplet form in the atmosphere, they were not suggesting that the "fragility" (i.e. rapid large amplitude variations in levels) detracted in any way from the important H2O greenhouse effect. And that's because those fast changes would be too brief to have more than a relatively momentary effect on the planetary surface temperature — as I am sure you were already aware.
Nor were the authors suggesting that the often extremely transient residence time of any one particular H2O molecule in the atmosphere would have any relevance either. Since at any one time it is the total amount of vaporous or cloud form, which produces the effect. Likewise with the somewhat longer residence time of an individual CO2 molecule (compared with the centuries/millennia duration of CO2 molecules en masse at a certain overall level).
You will note how I emphasized H2O's role at current ambient temperatures (say roughly minus 30 to plus 50 degreesC temperature range).
Where it gets interesting , JeffDylan, is if you do this thought experiment :- (a) picture all H2O suddenly removed from the atmosphere — result: within days "new" H2O has evaporated from land & sea, and the status quo is restored. Essentially nothing has changed (other than a brief blip of coolness from evaporation). Now (b) picture all CO2 suddenly removed from the atmosphere — result: a strong rapid negative feedback. Temperatures plummet, with widespread snow & frost precipitation on land and a fast-spreading layer of ice on the sea [with further sunlight reflection and further spread of sea-ice, to 100% coverage]. Ultimate result: a frozen world (and with minimal H2O in the atmosphere).
As you see — whichever way you look at it, CO2 (not H2O) is the temperature "control knob".
Moderator Response:[TD] Lest Jeff misunderstand your accurate statement about total H2O in the atmosphere: Clouds comprise liquid water ("cloud-droplet")--condensed water--not water vapor. Liquid water in the atmosphere interacts with infrared radiation (IR) differently than water vapor does. Notably, liquid water reflects IR in addition to absorbing it.
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Tom Dayton at 00:35 AM on 14 July 2017Models are unreliable
Clarifying MA Rodger's excellent reply to NorrisM: Risbey et al.'s approach demonstrated that the models do a good job of producing the sizes and durations of ENSO events. What the models do a poor job of is getting the timings ("phasings") right. Possibly the models never will get better at that, no matter how powerful the computers. Part of the reason for that shortcoming is that climate models are not intialized with the conditions yesterday in order to project the conditions tomorrow. Weather models do that, which is why weather models solve the "initial values" problem. In contrast, climate models are initialized with conditions far enough in the past so that by the time they get to projecting the future, the weather has canceled itself out, thereby wiping out any preferential effect of their particular choice of initial values. What constrains climate models to converge on their long run statistics regardless of their initial values, are the "boundary conditions" of the climate system, such as the net energy entering/leaving the top of the atmosphere. See the post on weather versus climate. After you read the Basic tabbed pane there, read the Advanced tabbed pane, and be sure to watch the video there.
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chriskoz at 23:10 PM on 13 July 2017Those 80 graphs that got used for climate myths
kar@4
very good point, although I don't think blogs like this offer the visual tools to the ir authors and commenters gto do so. Maybe make it a task to an admin or to Bob to add it in the "Insert" tab.
By the same token, contrarian studies when debunked for their errors and mistakes, are obviously oridinarily cited by the debunking authors. So, the contrarian authors, commonly producing shonky studies and succeeding in publishing them in the journal where editing/reviewing standards are not so high, receive the credits for each citation. They in fact, should have received "anti-credit" for demonstrated poor quality of their work. There should be an "anti-citation" choice available to the citing party for such cases.
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JeffDylan at 22:28 PM on 13 July 2017Water vapor is the most powerful greenhouse gas
I'm afraid I disagree with the rebuttal presented here. The explanation of how the water vapor feedback works is that the carbon dioxide greenhouse effect warms the atmosphere and enables it to absorb more water vapor. At the same time, the CO2 greenhouse heating causes more evaporation from the oceans and other liquid H2O sources. Since H2O vapor is the stronger greenhouse gas and there is much more of it, the small amount of greenhouse heating from CO2 is then amplified by this H2O vapor feedback. In this manner, the relatively small amount of greenhouse heating from CO2 nevertheless controls the much larger H2O feedback.
This argument, unfortunately, neglects the much larger greenhouse heating term resulting from the H2O vapor feedback being driven by the H2O vapor greenhouse effect itself. As was stated earlier, the greenhouse effect for H2O vapor is much stronger than that for CO2. At this point, climate change believers point out the very short residence time of H2O molecules as water vapor in the atmosphere as compared with CO2 molecules. In other words, H2O vapor may be the strongest greenhouse gas, but it is much more "short-lived" in the atmosphere that CO2. The greenhouse effect, however, does not depend explicitly on atmospheric lifetimes of the molecules, but only on the concentrations and IR spectral profile of the greenhouse gas. A greenhouse gas molecule will contribute to the greenhouse heating with a strength determined from its IR spectrum for as long as it is in the atmosphere. If it drops out of the atmosphere (due to condensation or precipitation), then it does not participate in the greenhouse effect until it re-evaporates. The frequent precipitation and re-evaporation of H2O does introduce short-term fluctations into the temperature profiles, but does not affect the longer term greenhouse heating.
Therefore, I must disagree with the "control knob" theory of carbon dioxide driving the water vapor feedback. It is the greenhouse heating from water vapor driving the water vapor feedback that actually dominates the greenhouse effect.
Moderator Response:[TD] You misunderstand the explanation, by focusing on "residence time." The residence time of individual molecules is irrelevant. Warmer air retains more total molecules of water vapor, regardless of how often individual molecules swap out. See the relevant post.
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MA Rodger at 19:27 PM on 13 July 2017Why the Republican Party's climate policy obstruction is indefensible
NorrisM @55,
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MA Rodger at 19:24 PM on 13 July 2017Models are unreliable
NorrisM @that other thread,
In the context of seeing the results of Multiple Linear Regression adjustment to the global temperature record (Foster and Rahmstorf (2011) adjusting for Sol, Vol & ENSO), you ask:-
"I do not know if you are able to do this but if you were to elimate both the 1998 El Nino and the 2015-2016 El Nino from the data, how would the models stack up to actual observations excluding those events?"
The linear assumption for temperature response in F&R2011when Sol,Vol&ENSO are accounted for does leave much unaccounted for while the models in accounting for actual forcings and climatic responses and so have no problem with the 'non-linear', but in so doing fail to reproduce the very important but unpredictable ENSO oscillations.
One approach to coping with ENSO unpredictability adopted by Risbey et al (2014) is to be selective of the model results and only include "those models with natural variability (represented by El Niño/Southern Oscillation) largely in phase with observations are selected from multi-model ensembles for comparison with observations."
And the finding - "These tests show that climate models have provided good estimates of 15-year trends, including for recent periods and for Pacific spatial trend patterns."
Another approach adopted by Huber & Knutti (2014) is to calculate the adjustment required to account for ENSO effects in the models. They conclude from this work "that there is little evidence for a systematic overestimation of the temperature response to increasing atmospheric CO2 concentrations in the CMIP5 ensemble."
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BaerbelW at 14:23 PM on 13 July 2017James Powell is wrong about the 99.99% AGW consensus
qwertie @9 - James Powell lists them at the end of his methods-post on his blog:
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nigelj at 10:57 AM on 13 July 2017Those 80 graphs that got used for climate myths
Ubrew @12, yes exactly.
Some years ago I saw a collection of about 100 studies claiming the mpw is hotter than recently, similar to the article. I checked the first page of 12 studies, just the graphs and abstracts. Many were on specific cities, some were so long term the wiggles in the graphs were meaningless, some were on parts of oceans so they werent a convincing selection, and I had no way of knowing if it included all studies on the MWP. It certainly didn't prove anything to me or add genuine clarity.
The IPCC reviews "all" the studies. I have more trust in their findings, than some suspiciously selective list by some sceptic.
The 80 studies in the article above sounds formidable, but I was immediately interested how many studies are there on northern hemisphere historical temperatures? As per the link I posted there are many hundreds and hundreds, so 80 is not so impressive, and we cannot be sure it is representative of the true weight of evidence.
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Eclectic at 10:42 AM on 13 July 2017It's too hard
Carn @65 :
"So while a lot will change to 2050, it could well be that the certain changes we desire simply will not arise." (unquote)
Yes Carn, that outcome is quite understandable — if we deliberately do nothing more than sit on our bums. Though I am not quite sure why you would wish to be so passive & fearful, in facing the clear and present danger from a situation [AGW] which is steadily worsening.
Please show some Can-Do attitude, and express your own ideas of how best to tackle the AGW problem. After all, to ignore the problem of rising CO2 atmospheric levels, is a failure of the personal responsibility that each of us has to help our neighbours (now and in the future).
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DPiepgrass at 09:34 AM on 13 July 2017James Powell is wrong about the 99.99% AGW consensus
I am curious who the four authors of 69,406 are that rejected AGW in peer-reviewed literature. Anyone know? I only know of 4 prominent contrarian climatologists – John Christy, Roy Spencer, Judith Curry, and Willie Soon – but only the first two are still publishing in the scientific literature AFAIK, and most likely Roy Spencer and John Christy would not attempt to publish something that explicitly rejects AGW.
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nigelj at 07:27 AM on 13 July 2017Why the Republican Party's climate policy obstruction is indefensible
NorrisM @70, I just couldn't find a graph of that. But I have visually compared the last 30 years of what models predict, against actual temperatures, with el nino removed. Models are still over estimating temperatures, but its just not by very much. I think that is the key thing its just not that different.
And it would only take a few more years of high temperatures to cancel this discrepency, and it should be noted 2017 is already showing quite high temperatures so far. It would also only take a slightly higher than anticipated acceleration near the middle or end of this century.
One theory is that oceans are simply absorbing more heat than originally thought, but that energy won't stay in the oecans forever (in simple terms)
I have always been upfront I'm not a climate scientist or any form of expert on it, but I do have a reasonable university education in a variety of things, and knowledge of the general climate debate. I'm interested in the science, but also the psychology, economics, and polictics, as these are personal interests of mine, and I did some psych. at university. So the climate issue encapsulates all the things I'm interested in, sort of by coincidence.
I think what counts is the long term trend once you get past about 20 years at least, so century scale predictions count most. These are based on the effects of CO2 and basic solar cycles that can be quantified and predicted. It's not possible to predict the wiggles along the way, and ten year periods, as ocean cycles are a bit random. That's my reading of the situation, and Im prettty clear on this in my own mind.
If we had experienced a pause of 20 years, I would say this would have been totally unanticipated, and our climate understanding would have been poor, but we just havent seen that. It's more of a 6- 8 year blip at most, if you look at any temperature data like giss. The overall upwards trend in this data is also just very clear now.
Moderator Response:[PS] Please follow other commentators and put discussion of model in the correct thread. A reply to NorrisM there already points to a page with the graph he has asked for. (and note of course obs are within error bars. Please do not ignore error bars when discussing model fit -that is just another way to avoid science in preference for rhetoric).
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nigelj at 06:45 AM on 13 July 2017Conservatives are again denying the very existence of global warming
Earthking doesn't refute the article in detail, and resorts to calling people names, and raising other issues to score points, and distract attention. However the issues he raises are all nonsense.
For example, we are not reliant on Michael Mann's early hockey stick study. Numerous other studies using different data and / or statistical techniques have found much the same hockey stick, eg Briffa or Espers studies.
The so called pause is insignificant, plainly obvious in the nasa giss global data as below:
data.giss.nasa.gov/gistemp/graphs_v3/
It's the long term 20 year plus trend that counts, and can be estimated. This is driven by greenhouse gases and fundamental quantifiable solar issues. Nobody can predict the wiggles along the way, or decadal length variability related to ocean cycles, because its partly random.
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