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Comments 53101 to 53150:

53101. KR at 04:33 AM on 6 October 2012
       It's not us
       Carbon500 - In some respects the graph you posted earlier is very interesting. Go to the Temperature Trends tool here, and look at GISTEMP (I will note in passing that you did not identify the source of your graph, or the selections from which it was generated - very bad form). Set a starting point of 1996 and smoothing of 1 month, as per that graph (source identified only from the URL), and look at the trend. 2σ uncertainties are calculated with added uncertainty due to autocorrelation, so this is a reasonably conservative estimate. Trend: 0.123 ±0.130 °C/decade (2σ) What does this set of data mean? There is a temperature trend of 0.123°C/decade, but it is is not quite statistically significant over that period. More data, more time is needed to truly distinguish that trend from the null hypothesis of no warming. But even your "no warming" example actually shows warming consistent with 30 and 40 year trends. Your claim that "this sixteen year old record cannot be ignored" is a strawman argument (it's not ignored, but it's not statistically significant - it's part of the data that is statistically significant), and indicates that you are lacking in statistical insight - as your presented evidence contradicts your claims (since it indeed shows warming). In other words, your use of that graph in an attempt to claim no warming is (IMO) quite demonstrative of denial myths - myths that sources like SkS are (I am happy to see) working to dismiss as the silliness they are. Finally, regarding experimental evidence of CO2 trapping heat - take a look at Harries 2001 directly showing energy entrapment at CO2 frequencies, which is discussed here regarding incremental effects as well as here regarding empirical evidence. If you disagree with the evidence, present your evidence on the appropriate threads. WRT water vapor, search using the SkS "Search" box for water vapor, or look at Google Scholar. Your claim that the role of CO2 as a greenhouse gas hasn't been experimentally proven is, to be blunt, complete and unsupported nonsense.
53102. Carbon500 at 03:39 AM on 6 October 2012
       It's not us
       KR: The point I made is that ice melting depends on many influences, and I think that caution is needed when attributing ice melt extent to CO2. That’s why I gave the Omstedt and Chen reference as an example. Regarding global temperatures, I am of course aware of the other graphs you mention, and the argument that the current stalling of warming is too short a period from which to draw firm conclusions – and yes, I am aware of the difference between weather and climate. (-snip-)? Sphaerica: (-snip-). Skywatcher: We agree that warming has in essence been in progress since the 19th century, but I’m more cautious than you about the 20th century. (-snip-). Another reason for my caution goes further back in the climatic record. (-snip-) Clearly Nature can surprise us. (-snip-) (-snip-). (-snip-)?
       Moderator Response: [DB] Multiple off-topic and inflammatory snipped. As constructed, this comment comprises a Gish Gallop. Future such comments will be deleted in their entirety.
53103. Philippe Chantreau at 03:08 AM on 6 October 2012
       Water vapor is the most powerful greenhouse gas
       Falkenherz, do not waste your time with arguments that rea not supported. This: "The level of temperature is dominated by factors in the stratosphere. We have very little water vapour in the stratosphere, so it in fact cannot be a dominant driver of global warming." Is nonsense. The first part is, and the second as well. There is enough water vapor in the stratosphere to make it a major factor in the stratospheric radiative balance, see Iacono and Clough (1995).
53104. Bernard J. at 01:41 AM on 6 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       I've just had a bit of a vent on the "Oh Shit" thread at Open Mind about the necessity for scientists to be heard on the issue of global warming. By way of analogy, in many states of Australia teachers and other professionals with similar responsibility are required by legal mandate to report suspected cases of child abuse. Now, it's not the responsibility of teachers and other professions to explicitly go out and police child welfare, but they have a professional duty to report any possibility of harm when they become aware of such. If the same principle applied to scientists there would be no antipathy to them speaking out on matters in which they have expert understanding - indeed, governments and the community should be listening with full attention, and tabloid current affairs reporters should be chasing fossil fuel executives in the streets and over fences. It just goes to show what we want to hear, and what we don't.
53105. villabolo at 01:01 AM on 6 October 2012
       Modelling the permafrost carbon feedback
       I imagine that as the temperature of the permafrost increases so does the metabolism of the methanogens. Microbial organisms are always sluggish at colder temperatures but their metabolism increases (exponentially?) as the soil temperature goes up. Has this factor been considered?
53106. Jim Eager at 00:38 AM on 6 October 2012
       Arctic Sea Ice Loss Has a Larger Impact than Antarctic Sea Ice Gains
       Chris, early last year Tamino looked at eccentricity vs a vis obliquity and precession in three posts, Glacial Cycles, part 1 http://tamino.wordpress.com/2011/01/27/glacial-cycles-part-1/ Glacial Cycles, part 1b http://tamino.wordpress.com/2011/01/28/glacial-cycles-part-1b/ and Glacial Cycles, part 2 http://tamino.wordpress.com/2011/01/29/glacial-cycles-part-2/
53107. KR at 00:29 AM on 6 October 2012
       Climate time lag
       Falkenherz - Several notes, and a comment. (1) Efforts by 'skeptics' aka deniers to claim that recent climate change is due to the sun, not anthropogenic greenhouse gases, fail. Either via bad/outdated/distorted TSI trends (the Washington Times Soon/Briggs article you asked about), or by disconnects between forcing and response times (as I pointed out in a previous post) invoked to cover the fact that insolation hasn't matched recent temperature changes. [Source] (2) Note as well that CO2 and the sun are not the only influences on climate. Aerosols, land use, ENSO, and internal variation all have roles in the forcings, and in the climate response. Therefore, do not expect exact tracking of any particular forcing component. (3) There are multiple response times, multiple lags in the climate (thus keeping this on topic here), in response to a forcing change. As a quick summary, the atmosphere responds quickly, while the oceans with a much larger thermal mass respond slowly. Tamino has discussed this at some length: multiple exponential decay factors here, and applying a two-box model to both modeled and observed temperatures here. A single lag model simply doesn't match the climate response to forcings, but a two-lag, two-box model matches quite well - and is supported by the physics. Air temperatures demonstrate quite fast swings WRT forcings - the oceans slower response shows larger changes over a longer period of time. (4) The IPCC 2007 statement you quoted clearly states that while uncertainties remain, estimates of insolation have improved over time. The estimate of +0.12 [+0.06 to +0.3] W/m^2 since 1750 expresses and encompasses that uncertainty - but even the most extreme TSI within that range is far too small to produce recent climate changes. Check the numbers - uncertainties are expressed with ranges, and you cannot take a statement of uncertainty as license to assume values far outside those uncertainties. (5) Important: You do not seem to have recognized the linear warming/linear forcing issue that Sphaerica and I discussed in comments from here to here (it goes unmentioned in your last response). The temperature pattern over the last 40-50 years is one of near linear increase, more than half a degree C. If the climate were responding to a halted TSI increase from mid-20th century (the observed insolation pattern) there would be a decreasing temperature trend towards equilibrium. The linear trend directly indicates a continually increasing forcing over that period. Claiming (as you are, again) that accumulated TSI may have hid out somewhere, and is now returning in what appears to be a linear pattern, is simply a leprechaun level argument. And hence dismissable. Comment: You seem to be searching quite hard, over multiple threads, for a 'skeptic' argument that holds up. While these conversations are quite pleasant, and may lead to additional clear discussions of these topics, I have to say that with just a little work on your part you would be able to find, or read, or understand, the collected information regarding and debunking these 'skeptic' arguments. Please - read the responses, read the opening posts, use the "Search" box here, or Google/Google Scholar. If there was a 'skeptic' argument that held up, that matched the data and the physics, that would become part of the mainstream theories - there isn't, and they aren't, for very good and well supported reasons.
53108. Bob Lacatena at 23:35 PM on 5 October 2012
       Water vapor is the most powerful greenhouse gas
       Falkenherz, I'm having a hard time parsing either of your quotations. Can you direct me to an actual place where a skeptic makes either of these claims (more clearly)? Right now they both look (to me) like pure gobbledygook. It's hard to argue against complete nonsense. [Changes in the global hydrologic cycle? Temperatures is dominated by the stratosphere? Huh?]
53109. chriskoz at 22:37 PM on 5 October 2012
       Arctic Sea Ice Loss Has a Larger Impact than Antarctic Sea Ice Gains
       Great article by Tamino. Even better comment thread on Tamino's site, which is a must read if you want to understand the details of insolation variances discussed. I have a question re counter-intuitive result of total solar energy input in NH vs SH being unaffected by orbital eccentricity (the Earth being on eliptical orbit closest to Sun in Jan). Eccentricity cycle of 100ka does match the last few glacial cycles. Based on that some poeple argue that changes in eccentricity have been dominant forcings in glacial/interglacial triggering model. But the fact that eccentricity does not affect the total insolation suggest that paradoxically, the forcings we are talking about here are very weak at best. Therefore other forcings must explain the triggering of glacials. Other orbital cycles (tilt and precession) are 41ka and 26ka respectively, so how do they coincide with 100ka glaciations? Tamino mentions Peter Huybers having the explanation, but does not provide the source. Does anyone have a pointer to this source? Thanks.
53110. BC at 22:33 PM on 5 October 2012
       Arctic Sea Ice Loss Has a Larger Impact than Antarctic Sea Ice Gains
       This is a great article. I had no idea that the insolation at the poles at midsummer is higher than all other latitudes, although getting sunlight for 24hrs makes it understandable. The other bit of info that stands out for me is how massive the impact of the albedo change is: 0.1W/m2 averaged over the whole world, and its impact is focussed on the Arctic. No wonder the temperature there is rising so much faster than elsewhere.
53111. Falkenherz at 22:01 PM on 5 October 2012
       Water vapor is the most powerful greenhouse gas
       Hi! Would you be so kind to include something on the following points: "To the extent that evaporation dominates over the surface-sensible heat flux, one can, in fact, argue that changes in the net radiation at the surface control the sensitivity of the global hydrologic cycle (the mean rate of precipitation or evaporation) rather than the sensitivity of surface temperatures." and "The level of temperature is dominated by factors in the stratosphere. We have very little water vapour in the stratosphere, so it in fact cannot be a dominant driver of global warming." Both are arguments from sceptics, but I did not find any hints here how to put them into context.
53112. Ari Jokimäki at 20:20 PM on 5 October 2012
       New research from last week 39/2012
       My pleasure, thanks for the interest. :)
53113. Falkenherz at 18:19 PM on 5 October 2012
       Climate time lag
       Thank you for the clarifying the "sphere calculation". With regards to the "thought experiment" and Bob #334; we are indeed "in the mind of a sceptic". So, my question was answered as such that we do not have direct global temperature data from before 1850, but only proxies. So, what do the proxies say? We are still at the point where a sceptic can say that we look too much on short term effect, which could be cause of climate chaotics, and we don't take into account strong but incremental long term TSI effects. The aerosols would be a very typical example of short term influences and as such does not connect to the point I am trying to explore. The question was, what is the relation between the temperature rise from 1700 to 1960, compared to 1960 to 2000? This is a way to answer the question, whether we see +0,6 degree since 1960 as mainly CO2-forced, or if there is a physical possibility that a TSI-lag from the last 3 centuries of raising TSI, which stopped in 1960, could still prevail. On the answer from KR #331: "you see almost no climate lag before the middle of the 20th century - and the invocation of a 50+ year lag suddenly kicking in once insolation starts to decrease" I cannot follow here; a "suddenly kicking in" can only be seen if you look at and compare the last 150 year period with the last 20 years. But I asked for the long term perspective, as any events from the last 20 years could probably be also attributed to accumulating factors of climate chaotics, as opposed to everything regarding TSI, which seems to be a very long-term process. KR, your other point I understand is that before 1960, we saw not much of a lag to TSI, but very immediate correlations to global temperature. This could be a very valid point. Could you please elaborate a bit more on this or give a link whith research on that topic? I admit this might be a little bit a loaded question, so I quote the IPCC to emphasize the direction of my inquiries, and please note the high degree of uncertainty expressed repeatedly: "The estimated direct radiative forcing due to changes in the solar output since 1750 is +0.12 [+0.06 to +0.3] W m–2, which is less than half of the estimate given in the TAR, with a low level of scientific understanding. The reduced radiative forcing estimate comes from a re-evaluation of the long-term change in solar irradiance since 1610 (the Maunder Minimum) based upon: a new reconstruction using a model of solar magnetic flux variations that does not invoke geomagnetic, cosmogenic or stellar proxies; improved understanding of recent solar variations and their relationship to physical processes; and re-evaluation of the variations of Sun-like stars. While this leads to an elevation in the level of scientific understanding from very low in the TAR to low in this assessment, uncertainties remain large because of the lack of direct observations and incomplete understanding of solar variability mechanisms over long time scales." http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-4.html (Maybe I should go back to discuss this under the article "it's the sun", but the topic seems to be a hybrid of there and here.)
53114. Kevin Hood at 18:03 PM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       The landmark environmental laws of the United States, such as the Wilderness Act, the Endangered Species Act, the Marine Mammal Protection Act and others, were passed in part due to activist scientists engaging in the issues. As long as scientists remain inactive: 1) People will figure that climate change is not that big of a deal (otherwise the scientists would be acting out, right?); 2) The active voices will be filled by denialists and lukewarmers; 3) Business as usual will prevail and the needed solutions will not be reached. Rachel Carson is a great example of an astute scientist who sought to change the dominant harmful paradigm - and did. Jim Hansen is another such hero. The time for complicity is long gone.
53115. Riccardo at 17:47 PM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       To spread knowledge is part of the work of any researcher, surely they are not paid for having fun in their labs for themselves. And the National Academies of Sciences have been founded to speak on scientific issues relevant to societies. We want them to speak. It's also a duty for any human being to alert others in potential danger. I really don't see any reason why someone should ask people not to ring the alarm bell if they have good reasons for concern. It would be kind of immoral.
53116. adelady at 12:46 PM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       John I wonder if Rachel called an alarmist and if that made any difference? Rachel Carson was seriously attacked during her lifetime - and you'll still see some people sneer at her in conversations about environmental issues. There was one gift she could bring to the table that very few people, let alone scientists, could do. Read "The Sea Around Us" to get the idea. She wrote like an angel.
53117. Bob Lacatena at 12:42 PM on 5 October 2012
       The Economic Damage of Climate Denial
       Phil,

       ...lack of means for this generation of westerners to be held accountable for damages in other countries...

       In other countries? What about their own? Other generations? What about their own? The only thing that ever stopped polluters was regulation. Most industrialists will pollute the heck out of their next-door neighbors if it turns a profit, and there is no financial incentive to avoid stomping on people who don't affect your profit margin, outside of regulation. The private sector can only solve problems that involve direct, measurable profit. National defense, education, health care for the elderly and chronically ill, and pollution control have no direct, measurable profit and so cannot be handled by a free market system. Free market capitalism is not a magic wand that solves every problem. That particular conservative fantasy is going to lead to a very, very bad place.
53118. chriskoz at 12:17 PM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       M Tucker@13, Rachel and here collegues were called "big alarmists" in late 50s by chemical companies who had vested interest in producing and selling as much DDT as possible. It's sad that she did not live up to her vindication that came in 70s. If Rachel lived today, she would just laugh how precisely the "deja vue" history repeated itself with tobacco companies denying cancer from smoking, CFC refrigerant producers denying ozone hole, and now FF lobby denying AGW. It's just a human nature to deny the problems caused by addictions, especially the addictions that are hard to ferret out. And FF addictions are the hardest type of addiction humanity ever dealt with.
53119. John Brookes at 11:09 AM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       As for scientists being activists, I'm puzzled by this. We all have a right to participate in public life. Is there some sort of rule that says that people who are expert in any one area should not put their views out there? So teachers should not talk about education, and doctors should not comment on health care, and fire fighters should butt out of debates about emergency services?
53120. scaddenp at 10:33 AM on 5 October 2012
       The Economic Damage of Climate Denial
       Clyde, you keep asking questions (china, will tax stop warming etc). When people answer your questions, then you simply ignore and repeat your point does not suggest you are very interested in answer. A statement like "you cant stop droughts and floods because you cant attribute any drought or flood to GW" doesnt give me any confidence in your engagement. I am all for private sector solving the issue - just give them the appropriate incentive. The trouble with laisez faire for this problem is the lack of means for this generation of westerners to be held accountable for damages in other countries in the succeeding generations. When your market solutions fail, you need government. My favourite - ban all new fossil fuel power plant construction and let the private sector work out the best alternative.
53121. JasonB at 09:40 AM on 5 October 2012
       The Economic Damage of Climate Denial
       Clyde: Still going on about China. It's like the fat kid pointing at a group of five skinny kids eating their lunch and asking why he should watch what he eats when, collectively, the five skinny kids eat more than he does! And this is despite the fact that China has 25 nuclear reactors under construction right now, and planning to have a nuclear capacity of 60 GWe by 2020, then 200 GWe by 2030, and 400 GWe by 2050; the fact that China has added 60 GW of wind power in six years and plans to add 150 GW by 2015; the fact that China has nearly 200 GW of installed hydropower; and the fact that while it is adding coal power plants, it is also decommissioning older, dirtier, and less efficient coal power plants at the same time. So not only is the fat kid complaining about the five skinny kids, he is ignoring the fact that the five skinny kids are dieting! "A carbon tax will not stop droughts & floods." Look, it's very simple. A carbon tax reduces CO2 emissions in two ways: 1. If you make something more expensive, you will reduce the consumption of it. Turning off lights when you leave the room, driving a more fuel-efficient car, installing LED or CFL lighting, etc. 2. If you make the price of fossil fuels more accurately reflect the true cost of burning them, you also make alternatives more competitive, encouraging their adoption. If you believe that capitalism works then it's hard to see how pricing carbon wouldn't reduce its emission. Then it's just a question of what the impact of reducing emissions will be. Science tells us that increasing greenhouse gasses will cause more droughts and floods, and increase their severity, and the recent history certainly seems to bear this out. Therefore emitting less carbon than we otherwise would have will logically prevent (and reduce the severity of) droughts and floods that we would have experienced otherwise. There's no magic here, it's pretty straightforward. "You seem to think a tax is the only solution." No, you seem to think a tax is the only solution. It isn't even the most common one! An ETS is in place in Europe and Australia and many other places (despite it being called a tax in Australia). An ETS even has one other trick up its sleeve: 3. You put a cap on how much carbon can be emitted, and gradually reduce that cap over time. This directly reduces emissions. "Let the private sector solve the problem." A tax and an ETS are letting the private sector solve the problem! Your proposal -- R&D funding by the taxpayer -- is the one that involves government intervention! A carbon tax and an ETS are called "market-based" solutions because the government doesn't try to pick winners, it simply makes fossil fuel solutions more expensive and leaves it up to the free market to innovate and find alternative solutions. Economists say that this is the cheapest and most efficient way to solve a problem.
53122. Doug Hutcheson at 09:18 AM on 5 October 2012
       Climate time lag
       KR and Spherica 331 - 333: Thank you for this exchange of ideas. The almost linear rising trend in temps must be due to an on-going increase in positive forcing and CO2 is the only reasonable culprit. The penny has dropped in my mind. I find small nuggets like this easy to understand, unlike some of the more esoteric discussions where I struggle to keep up.
53123. M Tucker at 08:03 AM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       Should scientists advocate for action on climate change? Should gridlock on the policy front, resistant corporations, lobbyists, bureaucrats and politicians, cause scientists to keep mum? Or, as Dana says, are climate scientists obligated to speak because "They're the ones who best understand the threat." Well, was Rachel Carson, marine biologist and conservationist, content to simply publish research in scientific journals or did she actively seek support from others, writers and scientists, and bring her case directly to the public? If you don’t have strong grassroots agitation nothing will get those government bureaucrats off their collective asses to stand up to corporate interests. I wonder if Rachel called an alarmist and if that made any difference?
53124. Bob Lacatena at 07:31 AM on 5 October 2012
       Climate time lag
       Just a note on dimming aerosols... even if they operated exclusively on visible light (as a simplification for consideration)... In the TSI scenario, the sun gets brighter but the dimming aerosols counteract that. In the CO2 scenario, the sun gets dimmer on average (due to the aerosols) but CO2 counteracts that (less inbound radiation, but also less outbound due to the GHE). In any event, dimming aerosols are a negative forcing, regardless of what other mechanisms are taking place. Admittedly, this is a simplification. The exact details won't be exactly the same, but... I still don't buy dimming aerosols as an argument against a TSI cause but not equally so against CO2. The linearly increasing temperatures, however, are another story. That kills TSI dead on the spot.
53125. Bob Loblaw at 07:21 AM on 5 October 2012
       Climate time lag
       Riccardo: yes, size distribution of aerosols is important. Aerosols can have two effects on radiation: absorption, or scattering. Absorption depends roughly on colour: something like dust doesn't absorb as much as something like soot. Scattering is according to Mie theory, and the wavelengths that are scattered most strongly are roughly the same as the size of the particles. Small particles = small wavelength, and the typical particle size in the atmosphere matches visible light. To scatter IR, you'd need larger particles, and they just tend to fall out of the air too fast. The smaller the particle, the longer they tend to stay - especially if they are injected into the stratosphere (e.g., volcanic eruptions) and can avoid getting rained out. Air molecules are much smaller, and follow Rayleigh scattering (see the Mie link above). This is strongly wavelength-dependent, and is the "blue sky" effect. Lots of aerosols of varying sizes tends to cause scattering across many wavelengths, and the "white" washes out the blue. Sun photometers are capable of taking direct sunlight readings and "backing out" the aerosol properties. AERONET is a world-wide monitoring effort.
53126. Bob Loblaw at 07:06 AM on 5 October 2012
       The Economic Damage of Climate Denial
       Clyde: "Bob Law suggests not buying stuff from them. I don't know if he means on a personal level, or the govt to stop trading with them, maybe a combo of both?" Trivial to do on the personal level. Remember that you said "Nobody is gonna make China do anything". I can easily make them stop selling stuff to me, so your statement is blatantly wrong. My sister won't buy Chinese stuff on principle. Enough people making the same decision, and it adds up. Elect a government that wants to do something, and yes, the government can put restrictions on trade. Look at how many times various countries have placed trade embargoes for human rights issues and stuff. We don't have to deal with China if we don't want to, so your talking point was nothing but rhetoric: yes, China has to listen to people they want to interact with, because interaction requires two consenting groups. If they stand alone, they can do what they want, but we're a major market for them and we do have a say. Are you trying to argue to support your "Nobody is gonna make China do anything" statement, or are you trying to distract everyone from your blatantly wrong statement in the hope that something else will stick? You're not giving me any reason to believe anything you say. [and, by the way, I don't live in the U.S.]
53127. Riccardo at 07:00 AM on 5 October 2012
       Climate time lag
       Sphaerica comment 330 "[...] the increase in dimming aerosols due to pollution/smog in that period, and that applies equally to any forcing (TSI or CO2)." The direct aerosol effect depends strongly on wavelength, being much larger at short wavelengths. It is often negleted in the infrared. KR and Spherica again in the simple zero-dimensional energy balance model, a linear temperature increase means a linearly increasing forcing and a constant energy imbalance, whatever the response time might be. Current linearly increasing temperature rules out a lagged response to the TSI forcing of the first half of the XX century. It also tells us that the response time can not be larger than belived (a few decades). A stronger evidence, though, is the increasing ocean heat content. A even stronger one would be a robust estimate of the radiatiative imbalance, which unfortunately we don't have and won't have in any foreseeable future.
53128. Bob Loblaw at 06:54 AM on 5 October 2012
       Climate time lag
       Sphaerica @ 330: No, we're not in disagreement. I'm still focusing on the thought experiment where TSI is the only forcing in play, and we're exploring how the system would react when TSI stops increasing. It's the counterargument to the "it's all solar, there is just a time lag" skeptic position. After all, a skeptic isn't going to try to convince me that the lag in the solar response is the result of a strong CO2 effect, will they? :-) You are correct in saying that in the real world (rather than skeptic-world) you do have to consider all the forcings, and the changes in forcings over time are rarely simple or step changes. Aerosols are a significant factor in the 1940-1970 period, and TSI plays a supporting role, too. Throw in a few volcanic eruptions, some El Nino for noise, and nothing looks as simple as Riccardo's graph.
53129. dana1981 at 06:37 AM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       Agreed Andy @11 - at this point after decades with hardly any serious policy efforts to reduce emissions, with time running out to avoid potentially catastrophic consequences and the evidence for those potential consequences growing ever stronger, I think climate scientists really are obligated to speak out. They're the ones who best understand the threat.
53130. dana1981 at 06:33 AM on 5 October 2012
       The Economic Damage of Climate Denial
       As Composer notes, the post talks about reflecting the true cost of carbon emissions (the SCC) in the price of their sources. I don't care if that's done via a carbon tax or cap and trade system or other mechanism. That's where the debate should be centered - what's the best mechanism to correct this economic failure? Clyde says let the private sector solve the problem - that's exactly what carbon pricing does. It gives the private sector an economic incentive to solve the problem via the free market. bvangerven @32 also makes a good point which the post does touch on a bit in the equity weights section. Right now the costs of climate change aren't being paid by those who are causing the problem, or at least not proportionately. Most of the damage is happening in the countries least responsible for the problem, as illustrated in Figure 1.
53131. Andy Skuce at 06:17 AM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       Having read Silver's chapter on climate science, I would agree with Dana's review. Silver says, correctly:"Uncertainty is an essential and nonnegotiable part of a forecast", yet in evaluating the forecasts he tends not to look at the uncertainties that were part of the forecast. Surely, looking at the uncertainties is also an essential part of evaluating a forecast. There are a number of typos, one amusing one (from the Kindle edition) quoting somebody at NASA who supposedly said (with my emphasis): “At NASA, I finally realized that the definition of rocket science is using relatively simple psychics to solve complex problems”. No wonder the O-rings failed. There are other strange statements, such as one claiming that the IPCC Arctic Ice shrinkage predictions "have done quite well", when they have, as is well known, greatly underestimated the rate of shrinkage. The book could have benefited from a critical reading by an expert. As for the implication that scientists who stray into advocacy risk losing credibility, I would argue that the opposite is true: a scientist who has credible information that has implications for human welfare has a professional and moral obligation to speak out on matters of public policy.
53132. KR at 06:05 AM on 5 October 2012
       Climate time lag
       Sphaerica - Yes, that's exactly my point. The only other forcings with significant ongoing change are aerosols, which are concomitant with emissions - reducing the CO2 forcing considerably, but summing to approximately linear in increase. [Source] Temperature response to a 'step' forcing would be an exponential decay towards equilibrium - but with an ongoing change in forcings, temperature will follow along (somewhere behind the curve, so to speak). Linear temperature increase (observed) is very strong evidence for ongoing increases in climate forcings - and again, that eliminates insolation as a cause.
53133. Composer99 at 06:02 AM on 5 October 2012
       The Economic Damage of Climate Denial
       Finally, I should add that the OP and the discussion - until your comment - had hardly anything to say on carbon taxes specifically. A carbon tax is a carbon pricing mechanism, but not all carbon pricing mechanisms are carbon taxes. It seems to me that it is you, Clyde, who is conflating carbon pricing with carbon taxes and then turning on others and suggesting that they "seem to think a tax is the only solution."
53134. Composer99 at 05:59 AM on 5 October 2012
       The Economic Damage of Climate Denial
       I should add with reference to droughts and floods that we can be confident reducing emissions will reduce increases in drought & flood events for much the same reason that reducing incidence of, say, HPV (through the recently-deployed mass immunization program against that suite of diseases) will reduce the incidence of cervical cancer.
53135. Composer99 at 05:55 AM on 5 October 2012
       The Economic Damage of Climate Denial
       Clyde: Your claim "A carbon tax will not stop droughts & floods. No one can say any one drought or flood was caused by GW" fails for the same reason claiming "Regulation of smoking will not stop lung cancer. No one can say any one incident of lung cancer was caused by smoking". It is well established that rapid warming will increase both the quantity and severity of drought and flood events. The evidence reviewed on this site, in IPCC reports, and other literature make this, IMO, abundantly clear. Other evidence shows - wait for it - an increasing trend in these sorts of meteorological events (e.g. the Munich Re data which has been widely shared here and elsewhere). All other things being equal, in the absence of warming there would be no increasing trend in droughts or floods. Unless a carbon price (whether a carbon tax, cap & trade, or fee & dividend - and now that I come to think of it, why is it your only focus on this thread appears to be on a tax?) fails to reduce emissions - and given the success of, say, the sulphuric acid controls (a cap & trade system) we can be confident that a market-based mechanism (which includes Pigovian taxes such as a carbon tax) will do the job - it follows that pricing carbon will reduce emissions, hence preventing continued growth of drought & flood events. Your argument: You seem to think a tax is the only solution. Let the private sector solve the problem. The advancement in fracking technology just one example. Can somebody tell me how higher taxes will stop GW? Let's say a tax is passed. Folks & companies decide to pay the tax & carry on with the status quo. Will the govt having more money stop GW? is also, IMO, quite flawed, for two reasons: (1) Fracking enables additional extraction and combustion of fossil methane. Last I checked, methane and its combustion products (CO2 and H2O) are greenhouse gases. It is no solution to the problem of carbon emissions. (2) I find it odd that you would presume individuals, businesses, and other organizations would voluntarily pay more for the kinds of goods that would be affected by carbon pricing. As far as I am aware, in most North American jurisdictions people are pretty keen on lowering their tax burden. I can't imagine that carbon taxes or similar pricing mechanisms would not lead to similar tax-avoidance behaviour (in this case, by decarbonising).
53136. Bob Lacatena at 05:41 AM on 5 October 2012
       Climate time lag
       KR, There's an important point in your comment... that the time-lag results are non-linear. They will taper off as you get closer and closer to equilibrium. The fact that warming is relatively constant is actually a good argument that whatever the forcing is, it must be increasing continually in order for warming to remain linear. And the only forcing that is continually increasing is CO2. This by itself is one more strong argument that CO2 must be the cause, because the time-lag argument, rather than pointing to some past forcing (TSI) as a cause of current temperature increases, actually does the exact opposite, and points against any forcing that is not only currently active but still increasing -- of which CO2 is the only candidate.
53137. KR at 05:11 AM on 5 October 2012
       Climate time lag
       Sphaerica - It should also be noted that some of the 1940's drop is due to (a) limited ocean coverage during WWII and (b) changing techniques for ocean sampling. HadCRUT4 (with corrections for those issues) shows a hiatus until the mid-1970's, but much less of one than HadCRUT3, for example. I completely agree that a 0.25 W/m^2 forcing difference is minor compared to observed changes - that translates to a 0.075°C direct temperature change, or something like < 0.25°C with fully realized feedbacks. Insolation changes are simply too small to explain the last 50 years of climate change - not to mention being of the wrong sign. Falkenherz - There is no mechanism whatsoever that would allow past TSI changes to "come out of the woodwork" 50 years later. Temperature change due to any initial forcing shift taper off over time as the imbalance is reduced, but the ongoing rate of change in global mean temperature shows that the forcings are continuing to increase. The ongoing rate of change (close to linear over the last 40 years) is chasing an ongoing forcing change. Insolation has in fact been decreasing over that time, and if anything is reducing the rate of warming. Many 'skeptic' arguments to claim "it's the sun", but when you examine such claims you see almost no climate lag before the middle of the 20th century - and the invocation of a 50+ year lag suddenly kicking in once insolation starts to decrease. In other words, such arguments are purest fantasy, unsupportable in the real world.
53138. BWTrainer at 05:02 AM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       "I think the conclusion was mostly a result of Silver seeing that we're making such little progress on the policy front that there's no sense in scientists sticking their necks up..." I was thinking it may be because he cut his teeth at the Booth School of Business at Chicago, where Milton Friedman pioneered free market libertarianism. Although Friedman was in favor of Pigovian taxes (applied to negative externalities, ie a carbon tax), so who knows. Or it could be as simple as he cares about science and thinks it will lose credibility, which can be possible when analysis and advocacy mix. I completely disagree with this; I think it's possible to advocate using sceintific analysis, like Hansen does. I also think scientists are worried, as they should be, that nothing is getting done, which has forced them to be more vocal. But some "purists" find this argument irrelevant and feel that scientists should stay quiet.
53139. Clyde at 04:33 AM on 5 October 2012
       The Economic Damage of Climate Denial
       For example, look at agricultural productivity being hit by droughts and the associated food cost increases. A carbon tax will not stop droughts & floods. No one can say any one drought or flood was caused by GW. Fine, then propose an alternative, for example a system like the one in British Columbia where the carbon tax is offset by reductions in other taxes. You seem to think a tax is the only solution. Let the private sector solve the problem. The advancement in fracking technology just one example. Can somebody tell me how higher taxes will stop GW? Let's say a tax is passed. Folks & companies decide to pay the tax & carry on with the status quo. Will the govt having more money stop GW? Now to China. I work for a company who sells them scarp metal. We ship them barges of scarp metal monthly. They might be trying "green energy" in their efforts to provide electric. Their also building coal plants at a much faster pace than their green energy plants. Bob Law suggests not buying stuff from them. I don't know if he means on a personal level, or the govt to stop trading with them, maybe a combo of both? Go through your house & see how many things are made in the USA only. We going to stop buying stuff from anybody who don't have a carbon tax to our liking? Sphaerica says "China wants in the WTO, but won't follow the rules unless it suits them." My point made. For those who think a trade war with China will make (pressure & convince) them to do anything is wrong IMO. It has nothing to do with right & wrong with them. It's pride/prestige plain & simple. They won't allow anybody to tell them what to do. Some of you are suggesting that just because one (or more) country won't do something doesn't mean we shouldn't. If you want to tax American's (on the basis of GW) regardless of what any other country does, good luck trying to get that passed into law on the fed level.
53140. Bob Lacatena at 03:59 AM on 5 October 2012
       Climate time lag
       Bob, I'm not sure I entirely agree with you, because the same applies to CO2 forcing. Why the hiatus in warming from 1945 to 1980? The usual answer (one I accept) is the increase in dimming aerosols due to pollution/smog in that period, and that applies equally to any forcing (TSI or CO2). But I would still question how a 0.25 W/m2 forcing amounts to anything notable, particularly given the quiet sun for the past 15 years or so. That's why the deniers had to introduce the idea of cosmic rays and cloud nucleation, because the TSI alone wasn't anywhere near strong enough.
53141. dana1981 at 01:49 AM on 5 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       chriskoz @7 - there does seem to be a bit of inconsistency with Silver acknowledging that uncertainty is an argument for action, but then at the end saying that climate scientists should stop advocating for action. I think the conclusion was mostly a result of Silver seeing that we're making such little progress on the policy front that there's no sense in scientists sticking their necks up, because they probably can't significantly speed up the process. He may be right about that, but you can't just quit trying to solve the biggest threat to humanity because you might fail.
53142. Bob Loblaw at 00:47 AM on 5 October 2012
       Climate time lag
       Falkenherz: Sphaerica has given you a couple of good diagrams. You can also see the effects of the 1:4 ratio in the equations in the text of the OP. Look at the one that has: S(1-A) = 4εσT4 ...and divide both sides by 4. The 4 disappears on the right, and we have S/4 on the left. ...now, you were asking about the "fails to appear" comment of mine, and said "So what you mean to say is, temp rises much higher/faster since roughly 1990 than ever before since 1850, and this cannot match to a TSI "lag pattern" from 1960 onwards? That is basically it, but we don't even need to look back to the 1800s, just look at T through the mid-1900s to now. Look at Riccardo's graph, and let's assume that his 0 time value represents 1960, when TSI stopped rising. What we would expect is to see temperature rising like it does in Riccardo's graph - most rapidly in the first few years, followed by a tapering off and eventual equilibrium. What you would not expect is to see temperatures steady for a couple of decades, then see a sharp rise like Riccardo's graph - but delayed to start around 1980 or so. From Riccardo's graph, we see that the flux imbalance starts at time 0, and gradually drops as T rises (due to extra IR loss to space as T rises). If the atmosphere did not warm for 20 years, the flux imbalance (delta-F) would remain at 1.0 for 20 years, and that energy has to go somewhere. Since it is not appearing in the atmosphere, where would it be hiding? (You won't get an answer from "skeptics".) That's where you would have to provide a plausible physical explanation to explain the "missing" energy and why it doesn't start to affect the atmosphere until many years later. That's the difficulty in the argument that the 1980s-onwards warming is delayed from earlier TSI increases. It ignores physics. As for pre-1850: we don't show measured temperatures for earlier times because the direct measurements don't exist. Think about when the thermometer and the concept of temperature were invented, and then think about how long it might take to get decent global coverage, and you'll see the problem. Before 1850, proxies are required - things that we can measure now, like tree rings, sediments, ice cores, etc. that have a record from the past that responds to temperature (but isn't a direct measurement of temperature). That's how we fill in the gaps from the past, and that the sort of data that goes into Mann's work (and other similar studies) and shows the Hockey Stick.
53143. John Brookes at 23:38 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       One thing that is interesting is that if anything, scientists have been getting less "alarmist" over time. That is, estimates of climate sensitivity have fallen, as have BAU emissions scenarios. Fake skeptics tend to be easy to identify, because they stick to the old predictions, and ignore the refinements. It remains entirely obvious that inaction is not an option.
53144. chriskoz at 23:08 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       Thanks Dana for an insightful review of Silver's book. I have an impression that Silver simply does not make enough effort to understand the physics of climate science deeply enough to make accurate judgement. Therefore he falls into the traps of "equal balance" and the "debate", wheareas there is no debate. That impression is reinforced after reading Mike Mann's review you pointed above. Mike's comments are important not only because he's an expert but also because he is an insider to some extent: Silver consulted him before writing the book. Mike is disapointed that Silver misrepresented a few point from that consultation. For example "the uncetainty about the influence of GW on ElNino" was spelled out in the book as "we don't know much about ElNino phenomenon". To me, that's an indication that Silver tried to repeat something from that consultation but misunderstood it and consequently distort it. Mike also points a problem with Silver's view of uncertainty:

       "Uncertainty cuts both ways, and in many respects -- be it the rapid decline in Arctic sea ice, or the melting of the ice sheets -- it is cutting against us. Uncertainty, as many economists recognize, is thus a reason for action, not inaction! I'm surprised someone as sharp as Nate just doesn't appear to get that."

       That is at odds with one of your good points that Silver accepts William Nordhaus' view. So I don't know what Silver wanted to opine here: - that scientist are "exaggerating" so we have some more time to address the problem, or - that we should be addressing the problem now because that's the correct response to uncertainty that works both ways. To me, those two opinions are mutually exclusive and cannot possibly cohexist in this book.
53145. ubrew12 at 23:07 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       "That the observed rate of warming has most likely been a bit lower than the IPCC projection is also not surprising considering all the short-term cooling influences over the past decade." The link indicated here is misfiring You mentioned Chinese aerosols as a cooling influence. I would also mention the huge amount of ice that's melted this past decade. Your Figure 5 in this discussion http://www.skepticalscience.com/GRACE-and-glaciers.html illustrates how dramatic this effect is.
53146. Bob Lacatena at 23:05 PM on 4 October 2012
       Climate time lag
       Another good image:
53147. Bob Lacatena at 22:47 PM on 4 October 2012
       Climate time lag
       Falkenherz, On 1/4 TSI... Imagine drawing a circle on the wall -- the earth. In the middle of the room is a lightbulb -- the sun. The light that falls in the circle is the light received by the earth from the sun... it's in the shape of a disk. But the earth isn't a circle, it's a sphere. That light isn't falling on a disk but on the surface of that sphere. Since the surface is curved, it has a larger surface area than the disk. This means two things. First, that the same amount of light is falling on a larger area at the edges of there sphere: And second (because the sphere is rotating) that the light is falling on both the front and the back of the sphere. In the end, the computation is very straightforward. The light being delivered covers the area of a circle (πr^2) while the light being received is spread out over the area of a sphere (4πr^2). So the amount of energy received per unit area on the earth is energy-delivered-per-unit-area times area-of-delivery divided by area-of-receipt, or: energy * πr^2 / 4πr^2 = energy / 4 1361 * πr^2 / 4πr^2 = 1361 / 4 = 340.25 W/m^2 Interestingly, the only denier I've seen that has been foolish enough to dispute this is Postma, but even he comes up with the same answer... he just claims the logic of the geometry is wrong.
53148. Kevin C at 21:38 PM on 4 October 2012
       Modelling the permafrost carbon feedback
       Thanks Andrew for those answers. I think it'll take me a while to grok the last one; my mental model of OLR clearly isn't sufficiently sophisticated at this stage. (It may of course be one of those things you never really understand till you've implemented your own.)
53149. chriskoz at 20:38 PM on 4 October 2012
       Modelling the permafrost carbon feedback
       Everybody here stipulates the consequences of C cycle disturbance we are causing. The disturbance in measured as just GtC, without actually qualifying the change of C oxidation/stability. What I mean here is that FF burning disturbance is far more severe than permafrost thawing disturbance. Because FF are sequestered in very stable form in 400Ma timeframe. That qualifies as at least 4000 times more stable as permafrost, which was likely thawed/refrozen in 100Ka interglacial cycles. That's why CO2 from FF is "far worse" than permafrost thawing for climate stability. That's why the Earth will have much harder time dealing with FF CO2: i.e. oceans that currently absorb some of it, will eventually degass it. While permafrost down to 3.5m may release CO2 that would eventually be effectively absorbed by the growing biosphere (i.e. lush forests may replace thundra if we return to hothouse) because the C in question is effectively part of the circulation in biosphere. So, when talking about carbon cycle changes, on a long run (that concious custodians of this planet should realy care, beyond 2100 which seams to be a limit of conciousness by politicians) one can ignore the effects of natural C feedbacks (that seem small by this study anyway) and concentrate on human disturbance that is unprecedented in millions of years.
53150. bvangerven at 20:05 PM on 4 October 2012
       The Economic Damage of Climate Denial
       The is one aspect missing in your article : You compare the cost of mitigation versus the – future – cost of adaptation. But not a word is said about who will pay the price in both cases. The cost of mitigation would be paid by the polluters. The cost of adaptation on the other hand would either be paid by the tax payers, or if the government completely fails to do its duty, adaptation will only be affordable for the rich elite, to protect their personal property, and the rest of us will be left in the lurch. This is also the main reason why representers of the fossil fuel industry plea for adaptation instead of mitigation. They are not really convinced that adaptation is cheaper, but it will be cheaper for their business.

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