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SocialBlunder at 06:44 AM on 15 February 2014Ice isn't melting
Does anyone track global snow/ice extent and relate it to albedo? I read in http://en.wikipedia.org/wiki/Stefan-Boltzmann_law#Temperature_of_the_Earth that the earth's albedo is 0.3. This means we can multiply the energy coming in by 0.7.
Could increase in air temperature be accurately predicted by the decrease in albedo?
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Dikran Marsupial at 06:41 AM on 15 February 2014MP Graham Stringer and CNN Crossfire are wrong about the 97% consensus on human-caused global warming
Russ R O.K. lets take the first one, what do you think the uncertainty is on the subject of GHG emissions in a "business as usual" scenario? Do you think they are going to be substantially less than RCP 8.5? If so, please explain why.
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Russ R. at 06:26 AM on 15 February 2014MP Graham Stringer and CNN Crossfire are wrong about the 97% consensus on human-caused global warming
dana1981,
I'm not sure whether or not you realize that it is an entirely reasonable position to agree with both of the "consensus" arguments (i.e. that the planet has warmed, and that human activities are responsible), and still not support "climate policy to address the problem".
The "97% consensus" that's you're reporting has nothing to say regarding any of the following, each of which is an essential link in the chain of reasoning that corrective policy action must be taken.
- How much will GHG emissions rise in a "business as usual" scenario?
- How much will atmospheric concentrations rise for that level of emissions?
- How sensitive is the climate to increased GHG concentrations?
- How long will it take for changes to manifest?
- How will those changes impact ecosystems, economies, societies and individuals (considering both positive and negative impacts)?
- What is the net cost / benefit of the expected changes (allowing for the possiblity and costs of adaptation)?
- What policy actions are politically feasible and economically viable?
- At best, how much can those actions actually reduce emissions below "business as usual"?
- With what probability of success?
- Over what time frame?
- At what cost, and with what unintended side-effects?
- And ultimately... will the probability-adjusted future benefits of policy action (discounted to present value), exceed the real direct and indirect costs of taking action, and will those costs and benefits be distributed equitably?
According to your definitions, I'm part of the "97% Consensus", but I still do not support the vast majority of proposed "climate policies" because I have numerous doubts relating to the dozen issues I've listed above.
FWIW, there are small number of "climate policies" that I would support even if climate change was not a problem, and they had no impact on emissions (e.g. ending energy subsidies).
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Andy Skuce at 05:57 AM on 15 February 2014A methane mystery: Scientists probe unanswered questions about methane and climate change
There is a new study out that looks at methane leaks in the US. Here is the press release.
Quick summary: Emissions measured from continent-wide top-down sampling are bigger than the bottom-up measurements. This is mostly due to a few one-in-a-thousand very leaky components that may get undersampled either randomly or by selection bias. Fracking activity itself gets a comparitive free pass. Some of the recent top-down studies that have shown large release rates cannot be representative of the ccountry as a whole if the methane budget is to be balanced, many factors, such as natural seepage rates and emissions from abandoned wells are poorly known.
Gas powered power stations are better for the climate than coal, at least over 100 year periods, but given the leak rates in the natural gas supply system, there are no full life-cycle emissions advantages for vehicles that use natural gas to replace diesel or gasoline.
Here's a link to a video where the lead author discusses the results.
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Dikran Marsupial at 05:13 AM on 15 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
DSL, slack-cutting is always a good idea, I was aiming for a concillatory tone (obviously I was rather off-target ;o), I was just trying to show that michaels comment was was not unreasonable and not an insult.
Just performing an ordinary google search for "Pinatubo climate model" works pretty well, and a Google Scholar search for "pinatubo climate model" brings up Hansens 1992 paper as the first hit for me. The real point is though that anybody that had looked into the reliability or otherwise of climate models should be particularly aware of the effects of Pinatubo as it provided a chance to test the predictive power of the models, and so has been very widely discussed.
There is nothing wrong with not knowing things (there is *plenty* I don't know, which is why I read much more than I write here), but in order to learn, you need to be able to admit that you don't know and not get upset if others tell you (this is a good guard against the Dunning-Kruger effect, so they are doing you a favour in the long run, even if it isn't pleasant at the time).
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Tom Dayton at 05:01 AM on 15 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Markoh: Following up on comments by Michael and Dikran--the U.S. National Research Council wrote a whole report in 2012: A National Strategy for Advancing Climate Modeling.
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DSL at 04:50 AM on 15 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Still, DM @ 86, perhaps some slack should be cut here. I mean, I did a Google Scholar search and only came up with ~8000 hits. Perhaps I over-limited my search string (pinatubo global mean surface temperature volcanic).
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DSL at 04:34 AM on 15 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
January GISS L-OTI is out (unadjusted): 0.72C.
DJ MEI = -.318
DEC PDO = -.41
CT SIE = lowest in the satellite period
CT SIA = 2nd lowest in the satellite period
Global SIA = 8th lowest in the latellite period
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barry1487 at 02:45 AM on 15 February 2014How we know the greenhouse effect isn't saturated
Chriskoz, that graphic is a close representation of how I imagine the increase in surface temps from a steady lapse rate but increasing height of troposphere from GHG warming. I believe there is a small caveat to add - the lapse rate does not remain quite constant, providing a small negative feedback, but not nearly enough to counteract the impact on surface temps from the elevated tropopause (this from meory - someone please correct if I am wrong).
I am always reminded that saying enough to be clear without reneging on the whole truth is often difficult to balance. Like a documentary maker who has a limited frame and time in which to capture the essence of the subject as well as possible.
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barry1487 at 02:22 AM on 15 February 2014Australia’s hottest year was no freak event: humans caused it
I knew that clouds were a complicated and uncertain factor and this adds some helpful detail. Thanks for the comments.
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babazaroni at 02:17 AM on 15 February 2014MP Graham Stringer and CNN Crossfire are wrong about the 97% consensus on human-caused global warming
I see one can look up the classifications on the Skeptical Science page.
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babazaroni at 02:12 AM on 15 February 2014MP Graham Stringer and CNN Crossfire are wrong about the 97% consensus on human-caused global warming
Is it possible to look up somehwere, like on the Concensus Project page, how a specific paper or author is classified?
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Dikran Marsupial at 02:11 AM on 15 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
To support what michael has written, climate modellers have conferences, where they discuss ways to improve their models (you need to know where the problems lie if you want to improve them, so talking about the failings of models is an important activity). Climate modellers also have journals where they publish papers explaining how to improve modelling of climate (again, you can't explain how to improve models without discussing the failings that justify the need for the improvement). Modellers also take part in Model Intercomparison Projects (e.g. CMIP3 and CMIP5, but there have been many others focussed on specific topics).
Your comment "However with Pinatubo the question is what effect it had on the years following 1991? It probably had an effect and thus would also change the gradient but I am unaware of any analysis quantifying the effect for what you are looking at. It probably exists." demonstrates that you are not familiar with the work that has been done on modelling, as the sucessful forcasting of the effects of Pinatubo was a useful exercise in evaluating climate models. It is not an insult to point this out; we all start knowing very little and learn more by listening to those more expert than ourselves. However looking for insults where none was intended is not going to help you learn, so you need to take such comments as useful advice.
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michael sweet at 02:01 AM on 15 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Markoh,
I do not see the insult that you are so concerned about. Clearly you do not understand how the climate models work since your questions are inappropriately phrased.
There have been a number of new posters lately (especially you) who have been extremely sensitive about responses to their questions. By the same standard, you have insulted me by your response. I only answered your question. Please point out what I said that was insulting.
I teach High School science and scientific models are discussed in class. The models are continually revised as new knowledge is gained. This statement is a general statement that is common knowledge. There is a meme at denier sites that models are not corrected as new knowledge is learned. That is false. Read the posts on Realclimate about climate models if you do not understand them. Which statement do you question that I made ? Your statement is to vague to respond specificly to.
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One Planet Only Forever at 01:43 AM on 15 February 2014Discussing global warming: why does this have to be so hard?
Marcoh @34,
To answer your question it is important to share my understanding of the fundamentals of the full issue.
- Developing the understanding of ways of living that are truly sustainable, ways that everyone is able to develop to and continue forever, are the only valid 'development'. Anything else is unsustainable and likely damaging to the future.
- That required development requires the best minds to be motivated to pursue that development, and the entire population to admire and support that effort.
- Greed and Intolerance are two attitudes that persist in human societies and that are counter-productive to development of a truly sustainable better future for all. It is important that those attitudes not be successful or popular. I add intolerance in this discussion because there is clear evidence that some of the greediest have been partnering with intolerant people to gain more political popular power.
- Benefiting from burning fossil fuels is not a sustainable way of living. It cannot be done by all current humans, leading to massive global conflict from the more powerful fighting to benefit more form it. And, in addition to being unsustainable, it is damaging in ways other than the harm caused by ‘fighting over it’.
- Therefore, the burning of fossil fuels, like many other unsustainable damaging activities, must only be a short-term transition to more sustainable ways of living. And the real benefit should only accrue to those who are least fortunate, to help them develop to decent sustainable better ways of life.
- Therefore the people benefiting from it most should have been focusing on development of more sustainable ways of living, no matter what their perceived 'lost opportunity' would be compared to how much more pleasure, profit, comfort or convenience they personally could get away from the unsustainable and damaging activity.
- The profit motive in the current socioeconomic system will not 'fundamentally' lead to the rapid, or any serious, development toward more sustainable ways of living. The greedy will fight against what is required because what is required is for them to not be able to get away with getting as much profit, pleasure, comfort and convenience as they might be able to.
- How the socioeconomic system gets changed to actually motivate humanity to develop toward the required sustainable better ways of life, to keep greed from succeeding, is the question that must be answered. Identifying greed and intolerance and affectively keeping those attitudes from succeeding is probably the first step.
- Greed and Intolerance are choices. So an important step would be to try to help people tempted by such attitudes to understand the unacceptability of those attitudes. However, it is important to acknowledge that some of these people may be very heavily under the influence of greed or intolerance. This may be the reason ‘discussing climate change can be difficult’.
Many people do not wish to support the development of a sustainable better future for all. Many people are only willing to ‘change their minds and their ways’ if someone else develops a cheaper and easier way for them to benefit more. The more sustainable and less damaging ways of living will always be more limiting for any current generation or group of people. That is the problem that must be solved, or a sustainable better future for humanity will not develop.
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Phil at 01:21 AM on 15 February 2014Discussing global warming: why does this have to be so hard?
mgardiner @40
Yes I agree it would be tricky; the scientist would need to be impartial (and sound it too) and it would be clear that he was reporting the politicians statement against the published scientific literature.
The discussion that funglestrumpet referred to (embedded in a page here) concludes with a "discussion" about whether the heat uptake by the ocean that is responsible for the "pause" in atmospheric temperature rise is measured or speculation - it would be nice if someone, on air, could have referred to a paper that did report the measurements, perhaps with a comment along the lines of "If Lord Lawson, or his advisors, thinks there is flaw in this paper, he would do climate science a favour by submitting his reasoning as a peer-reviewed scientific paper"
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Jim Eager at 00:40 AM on 15 February 2014How we know the greenhouse effect isn't saturated
Richard McGuire, the cold layers in the upper atmosphere stop impeding the escape of heat energy radiated from the surface simply because the density of CO2* falls below the threshold that insures that a photon will more likely be absorbed rather than continue to space unimpeded. Since that altitude is colder than the surface, less energy is radiated to space than is emitted by the surface, so the entire atmosphere below that altitude warms until outgoing energy matches incoming energy.
Adding more CO2 makes little direct difference at the surface, but it raises the altitude where CO2 radiates to space, and since that higher altitude is colder, the entire atmosphere below that altitude will warm still more until outgoing energy once again matches incoming energy.
*H2O is simply not a factor at the altitude where CO2 radiates to space as H2O is almost non-existant, having dropped below the concentration of CO2 between 6 and 8 km up, and fallen to only 3-4 ppm at the tropopause. However, as the atmosphere warms it will hold more H2O, thus raising the altitude where H2O radiates directly to space in wavelengths not absorbed by CO2, which will cause still more warming of the atmosphere below that altitude. This is known as the water vapour feedback.
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Markoh at 00:14 AM on 15 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
HK @ 83
Thanks for that. It makes sense. I am not an expert by any means, but I do know from non-climate modelling that the assumptions into the model are as important as the results out.
Good point about the accelerated ice loss. Suggests the earth is more effective/has more mechanisms for transporting heat to the cold reaches than models anticipated.
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Alexandre at 00:02 AM on 15 February 2014Discussing global warming: why does this have to be so hard?
I did not grasp the hypotheses where we can be lucky enough as to have AGW only as a "minor inconvenience". Even the lower end sensitivity means reaching more than 2ºC warming, even if after 2100 - specially if we have in mind that there's no credible policy proposal today of leaving any fosil fuel unburnt underground.
The article should make it clear that mitigation is necessary even if we're lucky enough to have a 1.5 ºC sensitivity - which is very unlikely.
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Bob Loblaw at 23:38 PM on 14 February 2014Australia’s hottest year was no freak event: humans caused it
barry:
KR has mentioned relative humidity (RH). While it has its place in humidity measurement, it is not an absolute quantity (the hint comes from the use of "relative" in the title), and misses out some key components of water vapour in the atmosphere.
The question is "relative to what?", and the answer is "the saturation humidity at the current temperature". The Clausius-Clapeyron relation tells us the saturation quantity as a function of temperature - it's roughly exponential, with higher values at higher temperatures. A relative humidity of 65% means that the absolute humidity is 65% of the saturation value at the current temperature.
Humidity can be measured in several related combinations of units that aren't "relative":
- vapour pressure (partial pressure of the water vapour gas)
- specific humidity (ratio, weight of water vapour to weight of dry air)
- absolute humidity (ratio, weight of water vapour to weight of moist air)
- dew point (temperature at which the current absolute humidity equals the saturation value)
Now, to get back to the cloud issue:
- warmer air can hold more water vapour before it reaches saturation
- air that isn't saturated needs to be cooled to the saturation point before clouds can form
in comparing two masses of air, the one that is "warmer and more moist" may reach saturation at a higher, lower, or the same temperature, depending on how much warmer and how much wetter (and this also depends on where along the exponential Clausius-Clapeyron curve you are).
In weather/climate, the three common ways of cooling air to form clouds all involve adiabatic cooling: as air rises, the pressure drops, and cooling occurs. The three ways of getting air to rise are:
- free convection (heating from the ground, heated air rises through overlying cooler air, due to density differences)
- push the air up over a mountain (orographic precipitation)
- push warm, moist air up over cold dense air (along fronts between air masses. Happens in cyclonic storms.)
So, if the air becomes more moist (in absolute terms), we also need to know if it is warmer or cooler. Let's take one example where the air is further from the saturation point. You can get a combination of:
- clouds won't form (doesn't cool enough as it rises - or in other words, doesn't rise enough)
- clouds form at a greater height
- clouds form a a similar hieght, but in a different form
Same options (in reverse) if the air is closer to saturation.
In summary, yes it is complex, and this is why cloud feedbacks are difficult to estimate wrt climate change. All evidence so far is that cloud feedback effects are small, however (globally-averaged).
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Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Markoh @76:
Honestly, I’m not a model expert, so I don’t know how much deep ocean warming they have predicted in the future. If they have predicted less deep ocean warming than we are seeing now and this pattern continues, it will certainly reduce the expected SLR from thermal expansion.
But it’s also worth noting that the models have missed the accelerated ice loss from Greenland and Antarctica. The annual contribution to SLR is now between 1 and 1.5 millimetre per year from Greenland (figure 56 in the link) and maybe about 0.5 millimetres from Antarctica (360 gigatonnes of ice = 1 mm). Add the melting mountain glaciers, and we’ll find that melting land ice is now the dominant cause of the SLR.
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Markoh at 23:26 PM on 14 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Michael Sweet @79
i ask a question and you respond with insults, which is unacceptable. However moving forward, you made statements of how models work. Is this knowledge from modelling you have personally done? If not can you please cite a source for the explanation?
Moderator Response:[JH] What is unacceptable is your mischaracterization of responses to you. Please cease and desist.
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ubrew12 at 23:23 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
mgardner@21: Sorry I took so long to get back to you. I guess, succinctly, what I was saying is there are two kinds of people these days: those who point to debt, and those who point to climate debt. The success of the climate obfuscation movement is the idea that you're being unpatriotic to think you can point to both. It's one or the other, pick a side. Since you never know who you are talking to anymore, CC is one of those subjects about which "silence is the better part of valor". And, of course, silence works for the fossils industry: The Silence of the Lambs.
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mgardner at 23:15 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
Phil@39
This is an interesting suggestion, but then you would have the claim that the scientist is not offering an impartial assessment, and you would have to have a scientist 'from the other side' as well, and then you would end up with the same problem, since scientists 'on the other side' tend to use the same approach as the politicians.
I'm just going to repeat the point I made earlier-- it's about what we in the USA call "playing to the base".
Scientists play to their own base; they get approval by being detailed, adhering to the rules, using language correctly, articulating any potential contradiction to the point of appearing equivocal, and so on.
Politicians do best when they can use simple slogans and emotive language, as you say.
And in this case, I would have to conclude that one 'side' is all about style and group identity, not substance. I am puzzled that many with scientific training ignore certain simple facts that point to this. How is it that, in the USA at least, there is this very strong correlation between climate skepticism, evolution skepticism, and a particular constellation of social/economic/political claims. There is no logical connection among these things, so what do they have in common?
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Bob Loblaw at 23:06 PM on 14 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
KR:
Thanks for the correction on Tamino's model.
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Bob Loblaw at 23:05 PM on 14 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
If Klapper really thinks that two different data sets are equivalent because the slope of the linear regression is the same, then perhaps he should review Anscombe's Quartet - four different data sets that have identical (to a certain precision);
- mean X and mean Y
- standard deviations (or variance) of X and Y
- same linear regression (slope and intercept)
- same correlation coefficient
...so, from the point of view of several common statistical tests, the four data sets might be thought of as "the same".
Yet when you graph them, you get (from the Wikipedia page linked to above):
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chriskoz at 23:03 PM on 14 February 2014How we know the greenhouse effect isn't saturated
Thanks Glenn & jg for the simplest possible explanation of the essence of GHE. I would not imagine such explanation be possible as the more i'm learning about GHE the less easy it becomes, as the grasping of many aspects of physics is required.
Your last three paragraphs do capture the essence of GHE from the planetary energy balance perspective. But on top of that, the average person or denier might ask: what does such effect has to do with supposed increase of surface temperature everyone is fearfully talking about? The answer is: as the 'action' moves higher, the temperature profile of the atmosphere must adjusts according to the temperature lapse rate. You have to refresh your knowledge about lapse rate (dry and wet) in order to understand why such adjustment is happening. Just as you have to recall the adiabatic processes in order to know why the air pressure and temperature decrease with altitude. Also you have to be aware why permanent gases like CO2 are "well mixed" while H2O precipitates at tropopause. Those basic processes are not explained in this article because no one seems to be denying them (although few years back, someone in US Congress was speculating that "excess CO2 will stay near ground because it's heavier than rest of gases", so even such basic high school topic sometimes requires debunking).
I don't want to discuss details of planetary response to GHG forcing: that's a separate topic. I just wanted to show a nice animation from RC, that captures the situation like 1000 words:
From there, you can now clearly see that a property of constant lapse rate - the slope of the blue line - in the atmosphere (more or less true in the first approximation) ensures that the increased temperature near the top of troposphere is transfered all the way back to the ground, resulting in GW as we the ground creatures, experience.
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Phil at 21:43 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
funglestrumpet @32
It is interesting (and depressing) that the BBC set up a debate between a climate scientist and a politician. Such a debate obviously places the climate scientist at a intrinsic disadvantage, since they are percieved as offering impartial expert advice in their field, and cannot therefore comment on matters like whether wind turbines are "a waste of money" or "an eyesore", or really employ emotive arguments. Lawson was placed at an advantage since he could offer unsubstantiated opinion on aspects of climate change which were outside Hoskins remit as a scientist. It would seem to me to be a much fairer approach to have two politicians debate the issue, and afterwardds have a scientist offer an impartial assessment of how the politicians views corresponded with the established science.
Another rather sad thought is that I, personally, cannot see a politician that would go head-to-head with Lawson who commands respect, Ed Davey, Lord Deben and Tim Yeo are possible candidates, but I feel the UK is badly in need of a climate change advocate. -
michael sweet at 21:26 PM on 14 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Scientists continualy review all their models. Your suggestion that they are not is simply false and demonstrates that you do not understand how science and models work. There is a question of how (and if) the physics in the models needs to be adjusted. Some of the models handle ocean heat well, others not so well. Scientists are trying to determine if this is because of random weather or climate. Adjustments are always made when new physics is learned.
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Richard McGuire at 21:15 PM on 14 February 2014How we know the greenhouse effect isn't saturated
The only way a myth can be debunked is if what is put up on science blogs such as this can be explained , debated and understood in the wider community. The saturation argument is a popular with climate change contrarians. I think the Real Climate "Saturated Gassy Argument" referred to @9 is well worth a read, though even there a better explanation is required as to why the cold layers in the upper atmosphere do not also impede the escape of heat energy radiated from the surface.
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denis.boarder at 20:12 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
The article is commendable, however the assumption is that we all work, and want to work, within a logical framework of rational, critical and sceptical thinking. We chose words carefully for the sake of political expedience but to what end?
Fine if we are at a dinner party, and civility is a prerequisite for not embarrassing the host, but in the wider world the dynamics of the conversation have changed. It is no longer a simple case of presenting evidence and logically debating the finer scientific points.Reasonability and patience has its limitations, even with friends. Probably has something to do with differing 'world views' ...???
I am sure there is no agenda to wreck the environment, but the motivation to maintain and extend a lifestyle pushes environmental impacts into a lower order of concern. The level of concern is perhaps inverse to the perceived value and limited by a short horizon. Strong headwinds blow against mitigation, despite, and perhaps because of an extremely muted and considered response from the scientific community. It is perhaps the time to turn off the 'impotent charm' and throw reasonableness out the window.
For all the good work going on within acedemia, and a not inconsiderable number of busy climate communicators, my perception, rightly or wrongly, is that significant will only be made once (excuse the pun) the temperature is raised.
The lead taken by Michael Mann (as one example) needs to be emulated if any real progress is to be made.
PS: To John Cook, Dana, John Abraham, Graham Readfern & Co. keep up the good work.
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Dikran Marsupial at 18:38 PM on 14 February 2014How we know the greenhouse effect isn't saturated
Richard McGuire - yes, CO2 is more effective in the upper atmosphere because the air is colder and less humid, however that is a more advanced topic than is intended to be covered in this particular article.
The argument that CO2 is saturated was first raised by Knut Angstrom in 1900, and was refuted in the forties and fifties by the work of Guy Callendar and Gilbert Plass, so the skeptic myth was busted over fifty years ago. The skeptics are rather behind the times to begin with on this one! This argument is a bit of a touchstone, a bit like the argument that the rise in atmospheric CO2 is natural; it is an indication that the "skeptic" simply can't be bothered to look into the science and find this myth was busted long ago.
There is a slightly more detailed article at RealCLimate that is well worth reading (in addition to the many others)
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barry1487 at 18:36 PM on 14 February 2014How we know the greenhouse effect isn't saturated
This remains one of the trickiest things to explain to us laypeople. Acronyms and nomenclature don't make it any easier.
Eg, the reference to 'TOA' - top of atmosphere. Unless someone is very conversant with the dynamics, then they wouldn't know if you were talking about the top of the troposphere or some place higher. Mention stratospheric cooling and one assumes that TOA refers to the upper limit of the troposphere. But mention some unnamed point where "heat is finally radiated out to space," and many people will inlcude the stratopshere, mesosphere, ionosphere - the whole of the atmosphere.
I know that the altitude of the troposphere is increasing and still have difficulty understanding which part of the atmosphere is the thinnest part where radiation finally escapes to space, and what exactly is meant by 'TOA'.
One explanation describes the atmosphere in even more discrete layers. Is the saturated layer radiating to a higher one that is less saturated (the blanket explanation)? Wouldn't more CO2 narrow the window at the highest altitude, where there should be no saturation? Or is saturation in the 15 micron band complete at all alittudes, leaving only the 'wings' of the spectral band unsaturated?
I've read the realclimate articles and dozens of others on saturation and explanations vary, seemingly contradictorily on some points. I suppose this might be because at the molecular level normal physical analogies don't quite capture the reality.
Still questing - any further clarity will be appreciated.
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Richard McGuire at 17:11 PM on 14 February 2014How we know the greenhouse effect isn't saturated
As someone without a backround in science I found the above explanation confusing. For example heat energy radiated back into space would need to pass through the high altitude cold air whether it came from near the surface or higher in the atmosphere. No explanation is given as to whether CO2 as it accumulates higher in the atmosphere is more effective at trapping heat because there is perhaps less water vapour. Which ever way I look at it I fear climate change sceptics have little to fear from this latest effort at myth busting.
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jsmith at 14:59 PM on 14 February 2014Southern sea ice is increasing
Exactly why do we need this page when we already have one called "Antarctica is gaining ice"? It seems like that page covers pretty much the same topic as this one does.
Moderator Response:[DB] This article deals specifically with sea ice in the vicinity of Antarctica. The other rebuttal deals with both land and sea-based ice.
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ubrew12 at 14:47 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
BC @22 said: "sea level rise for the last 22 years...[is] a... straight line" Physically, it should be exponential since its caused by temperature which is itself caused by CO2 and they are both exponential (i.e. all are hockey sticks). Google 'skeptical science sea level hockey stick' for evidence that it is holding to that curve. I took values from this sea level graph (1870-2010):
and eyeballed a 'best-fit' exponential function and got SLR (inches) = exp((year-1870)/57). This function gives an average rate of rise for the 20th century of 1.6mm/year, and an average rate of rise since 1990 of 3.4mm/year, so it's 'about right'. This function gives 4 feet of SLR by 2100, so it looks like my earlier posts were a bit 'alarmist'. But here's the thing: this function is based on SLR from the 20th century, which occurred almost exclusively without input from the ice sheets (that input started around 2000). This means the SLR from just ocean thermal expansion will bring 4 feet by 2100 (if this function is accurate!). Add meltwater to that and who knows where it'll end up. I don't know. More importantly, neither does the IPCC, and I think they need to communicate that uncertainty to the public because SLR can really loom as a property killer in the future.
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Markoh at 14:46 PM on 14 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Knapper @67
What you say about 1 data point (Pinatubu) on the middle of a linear regression not changing the trend is partially true. It will not change the gradient but will lift the overall line up or down.
However with Pinatubo the question is what effect it had on the years following 1991? It probably had an effect and thus would also change the gradient but I am unaware of any analysis quantifying the effect for what you are looking at. It probably exists.
So it is difficult to rule out Pinatubos effect without more data.
The comment by RPainting@ 70 is simply offensive name calling.
Moderator Response:[JH] Your assertion about Rob Painting's comment is patently false. Please cease playing the "victim card."
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Wol at 14:33 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
>>Moderator Response:[PS] in that spirit, please desist from terms like "denier" or "alarmist" which are inflammatory and counterproductive to a reasonable discussion. Thank you.<<
I think taking your line is actually playing from the deniers' hymn sheet: all too often they refuse to offer logical and factual arguments by falling back on semantics and the hair splitting of words.
I may have posted the below previously but it's worth repeating in this context: I have kept a log containg just some of the names that deniers have given in blogs to those who accept AGW. Perhaps calling someone a denier isn't so bad after all?
(-snip-)
Moderator Response:[DB] This is unhelpful. Inflammatory litany snipped.
[PS] Please read the comments policy. Terms like "alarmist" and "denier" do not help constructive debate. There are plenty of other places when rants are permitted.
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DSL at 14:17 PM on 14 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
Klapper, what I'm saying is that you can swim in statistics and never get physically wet. You dismiss Pinatubo because you can make it seem to effectively disappear by running linear regression across a specific period. Does Pinatubo actually have no effect on the temperature element of climate over the next 5-10 years? Of course it doesn't! If less solar energy reaches Earth's surface, global mean surface temperature is going to drop relative to what it would have been without the decrease in solar. Further, that drop is going to alter OHC uptake, as Rob pointed out. That will further affect GMST and ocean-atmosphere dynamics. There's probably a feedback from stratospheric warming as well, though I haven't read the literature on it. Pinatubo is written into GMST in complex ways. For you to claim that "Pinatubo has no effect on the warming rate of a trend from 1978 to 2007" is for you to claim that Pinatubo effectively didn't exist where climate is concerned. If Pinatubo doesn't occur, do you think we have precisely the same GMST monthly values from 2000-2007? Do we have the same shaped annual time series? Does ENSO follow the same path post, say, 1995?
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Wol at 14:00 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
CBDunkerson: >>This just doesn't match my experience. So far as I have seen, nearly everyone who contests AGW does so on the basis of disbelieving one or more of the three 'known and not controversial' items listed in the OP.<<
I fully agree: I have not debated (actually, given the nature of the issue, that's too strong a word) with a single sceptic who goes along with Abraham's profile.I'm sure we've all come up against the same problem: the way that sceptics make completely illogical and/or false statements of "fact" and then refuse to answer the refutations and bring up yet more of the same. Many of the "facts" are spread via the "useful idiots" who have bought into the misinformation from the fossil fuel industries lock stock and barrell.
I would like to think that head to head meetings with the likes of ******* and ****** to present the factual data (complete with full references) by real climate scientists could make them more aware of the scientific case, but I'm not that naive. People like ******** and ########## do appear to actually revel in their ignorance of basic science while at the same time repeating the same old arguments that have been shown time and time again to be invalid. (Be my guest and fill in the ***s and ####s yourself.)
As a conservative myself (small "c") I like to think that I can see both sides of any position and make up my mind independently. I struggle with the fact that so many right-wing folk seem to have problems with that, and will repeat the party line right or wrong. Fox news being a classic case and comical in its approach.
I don't see any answer, and Abraham's analysis is IMO just plain wrong.
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Markoh at 13:31 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
One Planet @33
You have restated that you think return on investment needs to be ignored for developing nations to presumably build fossil fuel infrastructure for a short duration, and then replace that infrastructure as a transition to renewable energy.
I don't see how that works. Can you please elaborate on how that would work, particularly where the funding would come from given the return on investment is not there??
Specifically, who would fund this?
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One Planet Only Forever at 12:52 PM on 14 February 2014Discussing global warming: why does this have to be so hard?
CBDunkerson @ 14,
(snip) [PS] This is over the line.
Rob Honeycutt @ 16,
I agree that the reason so many people willingly accept the unjustifiable claims hey made by the likes of Imhof is that, like Imhof, they do not expect to face the consequences of how they enjoy a better life, make more money, have more comfort or get more personal pleasure.
Rob Nicholls @ 29,
I believe your heartfelt belief that all people are basically good hearted is naïve. Some people clearly are only ever interested in getting away with getting more power, money, comfort or convenience any way they can get away with.
funglestrumpet@32,Your comment points out one of the unsavory characters I suggest Rob Nicholls and others need to accept are 'out there'.
In my opinion:
'Global warming and climate change' is a sub-set of the bigger issue of the 'acceptability of continuing the fundamentally unsustainable and clearly damaging pursuit of benefit from the burning of fossil fuels'.
Developing a better understanding of aspects of the issue is important, but many people appear to seek opportunity to claim 'uncertainty’ about the larger issue that has no uncertainty by finding a way to raise a question about the minutia of a part of the larger issue. These attempts to create the impressions of 'significant uncertainty about something there is no uncertainty about' are not ‘accidental’, they are deliberate.
The extraction and burning of fossil fuels cannot be continued for very much longer, and humanity has hundreds of millions, if not billions of years, to look forward to on this amazing planet. And there are many damaging impacts from the activity, including the impacts of the accumulation of excess CO2 (in the atmosphere and the oceans). There is also major harm caused by the conflict between powerful people fighting to get more of the potential benefit for themselves. Burning fossil fuels is an incredibly damaging activity ‘all things considered’.
An acceptable use of an unsustainable and damaging activity would be to address an ‘emergency’. I would accept that ‘emerging’ economies should be allowed to use the burning of fossil fuels to more rapidly transition their entire population into sustainable economic activity. However, this would have to be a brief transient phase. The 'economic efficiency or return-on-investment needs to be excluded from determining how long the unsustainable and damaging stage is allowed to continue.
After all, any activity relying on burning fossil fuels is ultimately a damaging dead end that needs to be stopped, the sooner the better. Those economic activities simply cannot have sustained growth. And since the objective is to ‘lift the least fortunate into a sustainable better way of living’ the only ones benefiting from the burning of fossil fuels should be those who are the least fortunate. The same goes for any other unsustainable and damaging activity like the use of harmful chemicals or using up (consuming), other non-renewable resources. Everyone already ‘more fortunate’ should be ‘getting by with sustainable virtually damage free ways of living’. That is the only viable future for humanity. Anything else would be unsustainable and unacceptable.
This ‘required development to sustainable activity model’ is challenged by the fact that sustainable activities will always be less profitable and less desired than the more damaging or less sustainable activities that ‘can be gotten away with because of popular support’. The ‘profit motive’ and ‘potential popularity’ clearly cannot be allowed to determine what is acceptable…because they clearly haven’t and won’t.
So the clear facts of matter are that the basis for determining the acceptability of prolonging the burning fossil fuels cannot be if it is ‘popular and profitable in the moment’. It cannot be based on the desires of the already fortunate to continue to benefit from unsustainable and damaging activity they have ‘grown fond of getting away with benefiting from’.
The increased understanding among the global population of the unacceptable and significant impacts of excess CO2 is just one of the ways to help raise awareness of the fundamentally unsustainable and damaging ways that many among the most fortunate ‘strive to get away with for as long as they can get away with’. Discussing and debating details of sub-sets of the larger issue needs to be clearly understood to not reduce the urgency of ‘changing the minds, attitudes and actions’ of the population so that humanity actually develops a sustainable better future for all life on this amazing planet.
Moderator Response:[PS] This is on thin ice. Please read the comments policy and abide by it.
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Glenn Tamblyn at 12:50 PM on 14 February 2014How we know the greenhouse effect isn't saturated
Actually jyyh, this myth only relates to the idea that adding more CO2 can't cause much more warming.
What you are referring obliquely through you reference to the magnifying glass is the 'it's the Sun' myth
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Markoh at 12:31 PM on 14 February 2014Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
HK @73
i was aware of the 10 fold difference in coefficient of thermal expansion of water at different temperatures.
Given that the models did not predict the heat going into the cold lower sections of the ocean over the last decade, caused by the trade winds, resulting in no appreciable surface temperature increase over the last decade when surface temperature increases were expected by the models, then have the models got the sea level rise predictions correct?
ie if the models didn't have that the heat was going into ocean depths over the last decade, do the models have the correct amount of heat going into the oceans in future prediction, and more importantly given the 10 fold difference in coefficient of thermal expansion, if the models predict heat going into the wrong part of the ocean the sea level rise predictions could be dramatically out?
Do the models need to be revised, if not why not?
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jyyh at 11:58 AM on 14 February 2014How we know the greenhouse effect isn't saturated
As the the myth in the article goes, the words "at the surface" could be bolded. "what of upper levels?", might a proper sceptic ask. The myth also imagines IR-radiation is the only form of energy effecting temperatures, though everyone knows (or at least could know) about the heat concentrated by a magnifying glass. -
scaddenp at 11:17 AM on 14 February 20142014 SkS Weekly News Roundup #6
Worth also pointing to the WG1 chapter "Climate models and their evaluation". (Ch 8 in AR4, ch9 in AR5). However, they do not do weather forecasting, have no skill at decadal level prediction and dont pretend to, and need to be evaluated against the robust predictions that they actually to make. More importantly, models are very important for predicting the future but not to validating AGW. A better question to ask is "are models skillful?"
However, there is a saying that "It is useless to attempt to reason a man out of a thing he was never reasoned into". Many see AGW as a challenge to their political values or their disbelief as a part of their tribal identity. Good luck changing those.
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jyyh at 11:13 AM on 14 February 2014How we know the greenhouse effect isn't saturated
yes, Tom Curtis, let's not get semantic on the words 'greenhouse gas' or 'greenhouse effect'. But I bet my explanation is better for 8-year-olds than for intentionally obtuse deniers. I also think there could be some gases that would rise the surface temperature of Venus still, so the greenhouse effect isn't saturated there either. I haven't come up with one but then I haven't particularly wanted to find out. Local concetrations of gases vary of course, but they stay the same and do not change their properties. 100% IR-absorbing material sounds like something scary from a scifi-novel, but that isn't what you said, the IR-photons can wiggle their way out of the planet between the molecules even in a 100% CO2 atmosphere.
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2014 SkS Weekly News Roundup #6
Chandra - Those truly in denial cannot be convinced; their confirmation bias prevents it. However, there is a lot to be said for pointing out such a persons errors to the others reading the discussion, people more willing to weigh the evidence presented.
In that regard I would highly recommend Raymond Pierrehumbert's presentation at the 2012 AGU Tyndall Lecture, Successful Predictions.The actual presentation starts at about 4:15 - in it Pierrehumbert discusses the many many successful predictions made about climate over the last 120 years.
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Tom Curtis at 10:00 AM on 14 February 2014How we know the greenhouse effect isn't saturated
jyhh @1, if you were being witty and making a pun, forgive my obtuseness.
If not, your argument is a non-sequitor. If CO2 absorbed at all IR wavelengths at its maximum strength, it would be saturated, even at current CO2 concentrations. That is because at maximum strength its effective altitude of emission is in the low stratosphere, which warms with altitude. Therefore increased CO2 would increase the effective altitude of emission, and hence increase the IR radiation to space.
Of course, my argument assumes hypothetically that the temperature structure of the atmosphere would remains the same in such a case. It is far from clear that that would be the case with 100% IR absorbing CO2. The hypothetical, however, is sufficient to show your argument fails logically. That is, you may be able to infer that which you wish to, but you would need far more premises to do so than you actually give.
As it happens, even with a 100% CO2 atmosphere, so long as the temperature at the effective altitude of radiation to space fell with increasing altitude, increased CO2 would result in less IR radiation to space at a given surface temperature, thereby requiring an increase in surface temperature to maintain the energy balance. That is, even 100% CO2 atmospheres need not be, and typically would not be, saturated.
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Tom Curtis at 09:50 AM on 14 February 2014How we know the greenhouse effect isn't saturated
potvinj @2, there are over 830 x 10^12 Kg of CO2 in the Earth's atmosphere (equivalent to 390 ppmv). The density of dry ice, ie, the precipitated form of CO2 is, 1,600 Kg per cubic meter. The area of the Earth is 510 x 10^12 meters squared. Consequently, if the atmospheric CO2 weref precipitated out into an even layer across the Earth's, there surface would be 1.6 Kg per square meter, or a layer 1 millimeter thick across the Earth's surface.
The question then becomes, can a layer a millimeter thick be effectively opaque to a given frequency. Could we, for example, coat a sheet of glass with a layer of paint less than a millimeter thick such that it would block out effectively all light?
Put in these terms, it is apparent that it is physically possible, and measurements have shown it is actually the case, that the atmosphere is effectively opaque to IR radiation in a limited bandwidth. This does not stop radiation of IR in that bandwidth to space, because the CO2, including CO2 above 80% of the CO2 in the atmosphere itself radiates in that bandwidth, with the radiation from the upper levels of CO2 reaching space.
The reason for the qualifier in the second bullet point is that CO2 absorbes less and less well as frequency moves from the center of the bandwidth of maximum absorption. The result is that IR radiation in those frequencies that would have previously escaped have an increasing chance of being absorbed with increased CO2. It should be noted that in the very center of the CO2 absorption band, the majority of emissions to space are from CO2 in the stratosphere, which is warmer than the upper troposphere, and warms with increased altitude. Consequently the mechanism described in the OP does not work (indeed, has the opposite effect) in the center of the absorption band. It does, however, work in the wings, so that the net effect is as described.
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