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Comments 39301 to 39350:

39301. Tom Curtis at 14:40 PM on 25 January 2014
       Three perfect grade debunkings of climate misinformation
       

       Poster @20, Jan 1997-Dec 2013 is 17 years.  As Warren Hindmarsh made a claim of "...a halt in the warming over the last 17 years or so..." I am required to use a 17 year interval to test his claim.  So yes, 17 years is a cherry pick, but it was Warren Hindmarsh's cherry pick, not mine. 

39302. From Peru at 13:56 PM on 25 January 2014
       More global warming will be worse for the economy, says Copenhagen Consensus Center
       

       oops!

       I should have written:

       "if you have a wealth of 10 000 $ and lose 5 000 $ you have a relatively bigger damage (half your wealth) than losing the same 5000 $ out of lets say, 100 000 $ ("just" a 5% loss)"

39303. Poster9662 at 13:53 PM on 25 January 2014
       Three perfect grade debunkings of climate misinformation
       

       Tom Curtis  Apologies but could you explain what appears (note I say appears not is) a contradiction in your post @10 above.  With regard to a pause or hiatus or whatever in global temperatures you state "Warren Hindmarsh @9, it is fairly easy to debunk the two fictions you mention by simply pointing out that they are fictions. This can be seen easilly for the satellite data on the SkS trend calculator. Just set the platform to UAH, and the start year to 1997.0 and you will see the trend is 0.93 +/- 0.208 C/decade. The central estimate, therefore is strongly positive, and while negative trends are not excluded, neither are trends 50% stronger than those predicted by the IPCC. Calling such a trend "a halt in the warming" at best shows a complete lack of understanding of the meaning of error bars"

        I may well have misunderstood but from what you write it seems you are  advocating starting at 1997 to "properly debunk the fact that accurate satellite measurements have shown a halt in the warming over the last 17years or so?"

       You then write  "Some people have misrepresented the ARGO data by only showing the 0-700 meter Ocean Heat Content, ie, by excluding 65% of the data. Excluding data like that because you do not like what it shows is fraudulent. Arguable, so also is the massive cherry pick involved in selecting 1997 (a very strong El Nino year, with temperatures far above trend rates) as a start year for your comparison."

       This suggests that picking 1997 as start year is somewhat fraudulent and is seemingly at odds with your earlier comment.  I expect I have misunderstood and apologies in advance if I have but would you clarify?

39304. From Peru at 13:45 PM on 25 January 2014
       More global warming will be worse for the economy, says Copenhagen Consensus Center
       

       The (social) discount rate (ignoring risk) is given by the Ramsey rule:

       r = δ +γ g

       Where:

       • r is the discount rate,
       • δ is the so-called "impatience rate",
       • g is the growth rate of comsumption (a.k.a. "economic growth") and
       • γ is a proportionality constant called "relative aversion to intertemporal inequality"

       δ for intergenerational matters must be zero (unless you value future generations less than the current one, a completely immoral prejudice), leaving the discount rate just as a function of economic growth.

       A positive intergenerational discount rate makes sense if and only if you assume that future generations will be richer than the current one, because a given damage is less serious if your wealth is bigger (i.e if you have a wealth of 10 000 $ and lose 5 000 $ you have a relatively bigger damage (half your wealth) than losing the same 500 $ out of lets say, 100 000 $ ("just" a 5% loss)).

       This is however a really bold assumption. No one knows for certain what the future wealth of people will be, and if Climate Change is really as serious as the evidence suggests, the economic growth could be offset by a growing economic climate-related damages.

       Now "growth" is a few % of GDP. When climate damages approach, as a fraction of GDP, that number, overall economic growth indices will have an ominous "-" sign, and the discount rate given above will be negative.

       Will that happen? I don't know, but I strongly suspect that it will. What do you think?

39305. Doug Hutcheson at 13:25 PM on 25 January 2014
       2014 SkS Weekly Digest #3
       

       Composer99, you have my heartfelt agreement. As a writer, I squirm at the times I have hit 'Submit', before noticing the typos. An 'Edit' feature would be sheerest delight.

39306. Tom Curtis at 13:11 PM on 25 January 2014
       More global warming will be worse for the economy, says Copenhagen Consensus Center
       

       jja @3 the discount rate accounts for several things.  One is the pure rate of prefference for present with respect to future gains.  To the extent that that is rational, it is based on an estimate of the probability that we will survive to enjoy the future gains.  A pot of gold now is twice as valuable as four pots of gold in 40 years if we only have a 12.5% chance of surviving the 40 years to recieve the gold.  There is, of course, more to it than that, but that is the gist.  Increasing the discount rate to account for this factor represents an implicit devaluation of future generations, and is morally objectionable.

       In addition, however, there is a discount to allow for the average expected rate of return.  That is, if we invest a trillion dollars now to mitigate global warming, would we have gained more if we had instead invested in economic growth?  Low discount rates (3% or less) are generally justified on this basis.

       There is a problem with even this.  It assumes ongoing economic growth with unmitigated global warming.  Given the ecological effects likely with unmitigated global warming, that is far from a certain proposition.  Indeed, if we were certain that unmitigated global warming would reverse economic growth (and we are not), that would require a negative discount rate.

39307. jja at 12:50 PM on 25 January 2014
       More global warming will be worse for the economy, says Copenhagen Consensus Center
       

       It is a distinct moral failure to use a positive discount rate when weighing the economic costs of mitigation and adaption  as compared to the current economic benefits of fossil fuels and future climate cost impacts.
       
       These people have no love for their children or grandchildren.
       
       They also have no concept of what the gross societal impacts will be from CURRENT CO2 atmospheric levels.  The most recent reports indicate that subtropical low clouds/fog will dissapear as the earth warms, and that our 2XCO2 Equilibrium Climate Sensitivity is closer to 4.3C.  This means that we will pass the atmospheric threshold of 2C by 2100 within the next 10 years.  It also means that we will likely suffer a catastrophic global economic collapse within the next 50.
       
       This economic collapse will destroy future economies and proves that the current A2r emissions pathway we are on deserves a NEGATIVE discount rate when weighing the the economic costs of mitigation and adaption as compared to the current economic benefits of fossil fuels and future climate cost impacts.
       
       A more realistic analysis of the current trajectory would prove that, even without a negative discount rate, the current global carbon budget, in terms of societal costs, is actually about equal to the global annual GDP. 

39308. Tom Curtis at 12:02 PM on 25 January 2014
       It’s all a Question of Balance
       

       Nichol @5, not only is the slight decrease in entropy caused by organizing a small amount of matter at the Earth's surface made possible by the very large energy flow from very low entropy (sunlight) to a very high entropy sink (space, at a temperature of about 3 K); but life works to increase the overall entropy at the Earth's surface.  Life mixes layers, transfers energy from warm daytime to cool night times and in other ways acts to increase entropy at the surface more than the decrease involved in its existence.  From a thermodynamic point of view, life is just a means of maximizing entropy faster. 

39309. Tom Curtis at 11:56 AM on 25 January 2014
       It’s all a Question of Balance
       

       Glenn, a fantastic article.  Thankyou.

39310. From Peru at 11:56 AM on 25 January 2014
       More global warming will be worse for the economy, says Copenhagen Consensus Center
       

       I just wonder what is the chance that the damages due to climate change , as a % of global GDP, will at some point be greater than the so-often mentioned GDP growth , resulting in a shrinking GDP that, among other things, imply a negative discount rate.

       
       Have anyone predicted a global-warming driven global recession?

       This kind of recession would be, unlike the 1930s and late 2000s ones, not a temporary one driven by a reversible process (a financial crisis), but one driven by an irreversible increase in costs (climate-related damages) that might last centuries if not millennia.

       
       

39311. denisaf at 11:26 AM on 25 January 2014
       It’s all a Question of Balance
       

       This article provides insight into how the greenhouse gas emissions from the use by industry of fossil fuels have disrupted the delicate heat balance. The feedback from global atmospheric warming will only slightly act to restore the balance. Reduction of the rate of emissions from fossil fuels (the popular anthropocentric antidote) will, at best, slow down the rate of warming. Knowledge of what has gone wrong is interesting but it is a diagnosis of the terminal illness of our civilization.

39312. Nichol at 10:26 AM on 25 January 2014
       It’s all a Question of Balance
       

       Excellent description! We are not in a static equilibrium, but in a highly dynamic one. The example of the see-saw by plg is a static equilibrium. It is difficult to think of a proper analogue of such a really dynamic equilibrium.. but let me try.

       I like to compare the earth system a bit with standing under a shower. The sun showers light onto us all the time, but the resulting heat is radiated away like the water runs down the drain. If you stand on the drain so not enough water can run away, you can make a big mess.

       Or we can think if a small stony river, meandering through a flat land. You can stand in the middle and lots of water comes towards you, but all of it passes by. If you start playing with the stones, you'll see that you can build a small dam that gently pushes the water to the left or right. You'll be surprised with the force that the water can be made to hit the river bank. It will even slowly change the course of the whole river. That is because you're playing with the precise balance of all that water coming, and going with great force. You only need to divert a small part of the energy sideways to get a big change.

39313. Nichol at 10:06 AM on 25 January 2014
       It’s all a Question of Balance
       

       Slightly off topic, though related. But fun.

       Here's a fun theory from a physicist that has been looking at the second law of thermodynamics, the one about entropy. He concludes that on a planet that has such a huge throughput of energy, both coming in, and going out .. you would expect that entropy can locally increase on earth. And that is exactly what happens when life evolves, and what life does.

       https://www.simonsfoundation.org/quanta/20140122-a-new-physics-theory-of-life/

39314. gws at 08:24 AM on 25 January 2014
       Mitigation Mosaic: How small steps can make a difference
       

       Great post, Baerbel!

       There is a new, useful overview of Germany's overall path here.

39315. Kiwiiano at 05:33 AM on 25 January 2014
       It’s all a Question of Balance
       

       Thanks for that HK, I've always felt that Hiroshima bombs as an index was unnecessary scare-tactics because of the burden of radiation, blast destruction, etc we associate with nuclear explosions. What would the heat gain equivalent expressed in gigatonnes of coal burning/hour rather than kilotonnes of TNT exploding? That might capture the feeling of inexorable increase better, although it's still going to produce numbers that are hard to grasp. 

39316. One Planet Only Forever at 05:03 AM on 25 January 2014
       More global warming will be worse for the economy, says Copenhagen Consensus Center
       

       These evaluations are not as helpful as they could be. A recognition of the unacceptability of creating any impact or potential impact on others, particularly future generations, is required for humanity to develop a sustainable better future for all life on this amazing planet.

       As compelling as these evaluations appear to be, they are still fundamentally flawed in a fairly obvious way. The situation is far less acceptable than is being presented. The evaluations ignore the blatant illegitimacy of one group getting benefit at the expense of others. They identify that nations benefiting less from unsustainable and damaging activities suffer more. However, they ignore the unfairness of prior generations benefiting at the expense of future generations. Some of them probably even ‘discount the costs faced by future generations’.

       Investors comparing their options will discount future potential costs because, from their perspective, money earned sooner is worth more than money earned later. That can be a legitimate way for an investor to choose between options when they will be the ones suffering any and all consequences of their decision and actions. It is unacceptable to extend that type of evaluation to this type of an issue. It is inappropriate to weight the benefit that one group of people get against the consequences faced by another group (a future generation).

       That type of evaluation continues to be used to build false justifications for all types of unsustainable and damaging activities. Obama mentioned it as a fundamental consideration regarding the potential approval of the Keystone XL Pipeline. They really did the math of what they think future generations will face, discounted it, and then compared it to what they thought the benefit would be for a portion of the current generation. The Alberta and Canadian Governments used exactly the same unacceptable evaluation as justification for approving the expansion of the admittedly damaging Shell Jackpine Oil Sands operation.

       Until these erroneous methods of 'determining and assigning value' are ended, the socioeconomic system will continue to develop unhealthy unsustainable and damaging economic activities, activities. The greedy among us will never stop trying to get away with benefiting unacceptably and illegitimately. It needs to be harder for them to 'get popular support' for suggestions that unsustainable and damaging activities people enjoy benefiting from are 'justified'. And they really should not be able to have any ‘value’ obtained from an unsustainable and damaging activity.

       For humanity to have a future, it is essential that actions by one person or group are not allowed to potentially negatively impact others, particularly not impact future generations. And they should not be able to benefit in a way that all others cannot also benefit from, forever. Until that fundamental requirement is globally achieved we will continue to see the success of leaders in industry, finance and politics whose actions are ultimately unsustainable and damaging.

       Greed and the actions it can motivate people to try to get away with are not good, but they can be ‘popular’, The potential popularity of inconsiderate attitudes and actions is the fundamental problem.

39317. One Planet Only Forever at 03:33 AM on 25 January 2014
       2014 SkS Weekly News Roundup #4A
       

       Wol @2.

       A more realistic way to look at the population issue is to recognize that it is the number of people whose lifestyle leads to the highest consumption and impacts that must be reduced.

       That is essentially what the point of Kyoto was all about. It was going to require the highest per-capita consumers and impacters to change their ways and help the less fortunate become more fortunate without becoming big per-capita consumers and impacters.

39318. One Planet Only Forever at 03:26 AM on 25 January 2014
       2014 SkS Weekly News Roundup #4A
       

       Wol @2.

       Overpopulation is a concern, but it has nothing to do with the fundamental lack of sustainability of human activity based on the consumption of non-renewable resources.

       There is no future for attempts to get benefit from the consumption of non-renweable resources. Eternal full-recycling of such resources would have a future. Burning them definitely doesn't.

39319. GRLCowan at 01:23 AM on 25 January 2014
       Three perfect grade debunkings of climate misinformation
       

       I will not tie the battle to mitigate global warming to the battle to legalize nuclear power. Mitigating global warming is to important to waste political capital by tying it to a method that is political poison, and probably unnecessary.

       No, it's necessary. Nuclear power is political poison exactly to the extent that it deprives governments of fossil fuel income (64 gigatonnes CO2 worth to date, according to Kharecha and Hansen). Any highly effective global warming mitigation method will excite the same sort of opposition.

39320. Composer99 at 00:55 AM on 25 January 2014
       2014 SkS Weekly Digest #3
       

       Since these are open threads, I'm going to put a plug in for adding a post-submission "Edit" feature for commnets the next time a change to the commenting user interface is considered.

39321. barry1487 at 00:24 AM on 25 January 2014
       Australia’s hottest year was no freak event: humans caused it
       

       Bruiser, thanks for the link.

       I can confirm that all the capitals and about 20 other stations I checked all had record-breaking solar exposure. I think it's safe to assume I didn't just chance upon the outliers. So I checked the colour maps against the values and they are a good fit. The problem, I realize, is that the resolution of the colour maps is too coarse. The difference between average and record-breakers is 1-2 Mj/sq/m, but the colour maps are in increments of 2 Mj/sq/m (annual), and 3 Mj/sq/m (long-term average). So I withdraw the earlier comparison. I could find no national average data, so can't crunch the numbers.

       I checked the warmest years for each state. 3 broke records in 2013, 4 were warmest in previous years. Of the 4 states that were warmer prior to 2013, solar exposure ranked 3rd for two of them, 8th for another, and 13th for NSW. This is based on the solar exposure data for one location in each capital. The SE data is only 24 years long, 1990 to present. Heavy caveats are applied. My extrapolation was spatially similar to yours (1 data point per state for me, 9 data points for the nation for you).

       With less than 50% correlation between highest solar exposure and warmest years for state based on limited data, solar exposure does not seem to be a dominant influence. I checked the diurnal record for the full period (from 1910). The trend is downwards. Nghts have warmed faster than days, indicating solar influence is not the dominant driver of rising temps, although this says little about the record 2013. The diurnal trend is more consistent with GHG forcing.

       Of the last 4 warmest years nationally, 2005 and 2013 were close in highest solar exposure and ENSO neutral. The next two warmest years (1998 3rd, 2002 4th) were El Nino years with average solar exposure (as best I could tell). We do not have solar exposure records prior to 1990.

       That's the best I could do with the data and time available. If I had national solar exposure data, I could make a better comparison with the global temperature record to check for correlation. From limited data (I checked temp record with solar exposure from a small number of stations - the capitals) the correlation does not seem to be strong. For example, while Darwin Airport had it's 3rd highest solar exposure of the 24-year record in 2006, that year saw the 18th highest temperature in the same period, same location. I may do more work when I have time - like plotting and comparing time series of both indices for various locations. But check it out more thoroughly for yourself if you feel inclined.

       Barry.

39322. Dikran Marsupial at 19:43 PM on 24 January 2014
       Global warming theory isn't falsifiable
       

       My theory that Tom could give a good answer was not falsified, thanks Tom!

       The thing that I would point out is that the attempts to falsify the models never seem to mention the decline in Arctic sea ice, which is much more obviously wrong in the models than the tropical trophospheric hotspot (both of which the climate modellers are well aware and quite happy to discuss).  I wonder why that might be ;o)

       Falsifiability is a useful concept in science in the same way that frequentist hypothesis tests are, both have severe limitations and both are widely misunderstood.  Used properly, however, they are both good methods of providing basic sanity checks that help us not to jump to conclusions (i.e. they help us to be self-skeptical - which is the most important form of skepticism, if you haven't got that, you haven't got any other sort!).

39323. ajki at 18:24 PM on 24 January 2014
       2014 SkS Weekly News Roundup #4A
       

       Meanwhile in the arctic region...

       The Arctic Frontiers conference was held in Tromsö, Norway, this week. Irene Quaile from Deutsche Welle covers this event on her blog, starting with "Arctic Frontiers: Humans in the Arctic".

       While the arctic regions are undergoing much more of a change than other regions as a result of global warming, a kind of unwillingness to deal with the problems can be noticed, states Quaile in her recent blog "Climate Change: Arctic in denial?" where she cites Kari Marie Norgaard (Professor of Sociology at the University of Oregon) and Per Espen Stoknes (Associate Professor at the Center for Climate Strategy of the Norwegian Business Institute NBI) who are currently studying this phenomenon.

39324. denis.boarder at 15:51 PM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       Tom... many thanks. I appreciate your time. Will have a good read.

39325. Tom Curtis at 14:59 PM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       denis.boarder @16, the comment is basically correct right up to the last two sentences.  Specifically, the three dominant short term fluctuations that influence Australian climate are:

       The Southern Annular Mode (SAM), which strongly influences whether the southern states (Western Australia, South Australia, Victoria and Tasmania) will have wet or dry winters.

       The Indian Ocean Dipole (IOD), which influences spring (from memory) rainfall in the southern states, and summer rainfall in the top end (ie, northern Australia, particularly northern Western Australian and the Northern Territory).

       The El Nino Southern Oscillation (ENSO), which influences eastern state rainfall and temperatures, particularly Queensland and New South Wales.

       The last two sentences in the comment, however, are simply false.  The person writting the comment appears to have assumed global warming is supposed to cancel the effects of the drivers of weather.  That is a logical absurdity equivalent to assuming that because global warming is supposed to make things warmer, each night must be warmer than the preceding day.

       Rather than cancelling the effects of existing drivers of weather, global warming modifies those effects.  Thus warmer tropical waters results in more rainfall IOD positive states with more rainfall in northern Australia than past IOD positive states, in IOD negative states with more rainfall than past IOD negative states.  The result is a clear positive trend in northern Australian rainfall:

       

       It is interesting in this respect to compare 2013 with 1919.  Both years were significantly dryer in northern Australia than were surrounding years, consistent with your commentors claims - but the rainfall anomaly for 1919 was -129.35 mm, compared to -33.56 mm in 2013.  That is a difference of almost a 100 mm, and is inexplicable on the comment author's theory that its just weather, but is predicted as a consequence of global warming.

       Likewise, the SAM varies as a partern of weather, but global warming predicts that on top of that there will be a long term trend to more positive SAM conditions:

       

       (Updated graph available here.)

       It is that trend, explicable, and indeed predicted as a consequence of global warming, but inexplicable in terms of the SAM which explains southern Western Australia's long term drying trend:

       

       Note that the SAM was positve negative in 2013 (see updated chart in link), which explains why 2013 was wetter than most recent years in WA.  It does not explain why it was dryer than average, or why a wet year in the 2000s is about as wet as a dry year in the early 1900s.

       Similarly with ENSO, it was the strong La Nina which explained the record breaking floods in Queensland and Victoria in late 2010 and early 2011 (although not why they were record breaking); but it does not explain why the record broken for flood effected area in Queensland was set only in the preceding March during an El Nino event.  

39326. Wol at 14:51 PM on 24 January 2014
       2014 SkS Weekly News Roundup #4A
       

       >>The only sustainable future for humanity or an economy...........<<

       
       The fundamental problem for climate change, resources, biodiversity etc etc is overpopulation. That is the ONLY thing that matters.

       Some are keen to say that population is forecast to stabilise at 9Bn plus, but nobody seems to address the question of whether even *that* number is remotely sustainable. Bear in mind that everyone would like to see the developing countries attaining a high standard of living.

       Various estimates of sustainable population have come up with hugely differing results, but almost all put the number way below 9Bn IF a more equal standard of living is taken as read.

       Taking action on carbon without addressing the real problem is like running up the down escalator without first pushing the "Stop" button.

39327. denis.boarder at 13:02 PM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       Can anyone help?... (Not sure if this is the right area to ask this question)

       I would appreciate an opinion on the following comment posted in response to Graham Readfearn's recent Guardian blog. Having found information on ENSO, SAM and IOD I must admit I struggle to understand the relationships, specifically in response to the assertion below.

       The Comment
       Australian weather is not about ENSO on its own there are the SAM and the IOD These tend to reinforce each other depending upon their Phase. Australia has just experienced a multi year strong La-Nina which was not reinforced either by the SAM or the IOD. The La-Nina ended in 2012 every time we swing from a strong La-Nina we often experience a strongly positive SAM this keeps the usual west east weather patterns and cold fronts well to the south, similarly the OID is keeping WA dry and the northern Monsoon season has been delayed and mild. This is the exact opposite of AGW predictions, as the earth warms the Monsoon season is supposed to extend in duration and latitude. We are witnessing the weather not AGW, the last time something similar happened was in 1919.

        

39328. Tom Curtis at 09:52 AM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       franklefkin @13, it is true that I chose the only satellite index with global coverage.  However, Warren referred to "... accurate satellite measurements ..." (note the plural), which appears to indicate that both satellite records show the pattern.  His claim is false, therefore, if either does not.  Therefore showing UAH was sufficient to show his claim to be fiction.  Had he specified the RSS record only, then his claim would have been true, but massively cherry picked and misleading.

       Of course, it is possible that by "accurate satellite measurements" he meant "those, and only those, satellite measurements that make my statement true"; ie, that he was obliquiely cherry picking.  In that case I misinterpreted him and his first claim was true but a massive cherry pick.

       Unfortunately, while it is possible to interpret Warren as saying something true (though cherry picked as to source), or something not cherry picked as to source beyond the limitations to satellites, but false - we cannot be so charitable with you.  You want his claim to refer to both satellite records so that it is only a limited cherry pick, but also to only refer to the RSS so that it is true.  Alternatively, you want his claim to refer to both, but for a conjunction to be true when one of the conjuncts is false.

       You compound the irrationality by concluding "...but the question asked was about the satellite records, not about a highly accurate satellite record" when Warren in fact specified "accurate satellite records"  (my emphasis in both quotes).

39329. scaddenp at 09:34 AM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       Well I would say that there are several ways to "proper" debunk the "hasnt warmed x years". Firstly by pointing out that 17 years is a cherry pick - start with monster El Nino and end with ESNO neutral. Compare with using 16 years and 19 years. Second there is "accurate satellite measurements" - accurate according to who? Both UAH and RSS struggle with the numerous issues associated with drift and extracting LTT. The recent Cowtan and Way paper points the way to disintangling drift but hasnt been done to my knowledge. If you overlay the records, you will see that the satellite records for lower troposphere have a much stronger response to both La Nina and El Nino than the surface temperature record. Does the lower troposphere really react that differently to the surface or is that an artifact? Either way take "accurate" with a grain of salt. How do you think those temperature records (and subquently the trends) are going to react to the next El Nino or do you think such events are gone for good? (Look at past records for ENSO index for this).

       Finally temperature trends are very noisy and that is why climate is defined on a 30 year trend. Less noisy is the OHC and to the oceans is where most heat is going. No sign of a pause in global warming there.

39330. Tom Curtis at 09:30 AM on 24 January 2014
       Global warming theory isn't falsifiable
       

       jacklongley @1, falsifiability is a strange concept of limited use in science, despite its popularity.  The reason is that when we test any hypothesis, we must make background assumptions both about other conditions, and about how our instruments work.  These background assumptions then form auxilliary hypotheses which are tested alongside the hypothesis we actually desire to test.  As a consequence, if our test gives a negative result, we do not falsify any individual hypothesis (including the one we wanted to test).  Rather we falsify the conjunction of the hypotheses.  We show that not all of them can be true together.  This is known as the Duhem-Quine Thesis, after its two independent "discoverers".

       To illustrate this, consider Dikran Marsupial's test of "global climate change theories" from 2 above.  He claims that a centenial negative trend in temperatures would falsify the theory.  Of course, if that centenial trend coincided with a 50% reduction of solar physics, the theory would not be falsified.  Dikran is quite aware of this, and covered himself with the auxilliary clause that the trend occured "in the absence of any other change in the forcings that could explain it".

       In very simple theories, we can radically reduce the number of auxilliary hypotheses making the particular hypothesis of interest more amenable to falsification in a "crucial test".  We can also vary our experimental methods so that we are testing the theory with different auxilliary hypotheses.  Thus, for very simple hypotheses, we can reduce the impact of the Duhem-Quine Thesis, but we can never entirely avoid it.

       Because AGW is a complex theory with many auxilliary hypotheses, it is difficult to develop "crucial tests", ie, any individual test that will show it to be false.  In fact, in the very short term it is impossible.  What we can do is develop "crucial tests" for important elements of the theory, but not for the whole theory at once.  We can also measure relative likilihood with respect to competing theories.  Doing so, we can show that AGW easilly is a superior theory to its competitors.  But we cannot pick a single experiment to falsify the theory, so you will not find much discussion of falsification with respect to AGW.

       When you do, it is often for critics of AGW who take a farcically simplistic view of falsification to declare that "AGW is falsified".  Spencer and Christy played this game for a while, declaring the UAH satellite temperature index falsified AGW.  Then (on several occasions) they were embarrassed when it was shown that their auxilliary hypothesis that they had eliminated all significant errors from their temperature record was what was false, and that UAH tends to confirm rather than falsify AGW.

       Lucia Liljegren has played a similar game, several times declaring that the recent temperature record falsifies IPCC predictions.  She has neglected, however, the IPCC auxilliary hypothesis of neutral ENSO conditions*.  She has merely falsified the conjunction of hypotheses that (CO2 forcing is increasing & climate sensitivity is in the IPCC range & ENSO fluctuations do not effect global temperatures & ....).  As her third, tacit, auxilliary hypothesis is known to be false, her results are massively uninteresting.  (She also uses a very simplistic definition of falsification in which events with a 1in 20 probability of occuring in a theory are supposed to falify the theory; something Popper would have considered ludicrous.)

       Despite the limitations of the Duhem-Quine Thesis, it is possible to extend the emperical content of theories, and the climate science community is doing just that with the theory of AGW.  They are going to extraordinary lengths to do so.  Because of the complexity of climate science, in some areas that is difficult and slow going.  It is very noticable, however, that it is the people rejecting AGW, the Republicans in the US, the Harper government in Canada, who are defunding research.  They are so confident in their position, it appears, that they dare not put it to empirical test.

       There is a lot more that could be said on this very interesting subject, but I am out of time, and this post is long enough as is.  I'll respond later if you want to explore the subject further.

        

       (* The IPCC auxilliary hypothesis is not that ENSO does not effect temperatures, but that ENSO fluctuations cannot be predicted except in the very short term, and so cannot be included in IPCC projections.  That does mean that IPCC predictions in the short term cannot be properly tested unless the effect of ENSO is removed from the temperature record.  Lucia does not do that, thereby assuming as a tacit auxilliary hypothesis that ENSO does not effect global temperatures.)

39331. HK at 09:26 AM on 24 January 2014
       It’s all a Question of Balance
       

       Excellent summary of the basics, Glenn. This is really what the disruption of the climate boils down to. Your conclusion is pretty much the same as James Hansen’s when he wrote that the global energy imbalance gives us the most fundamental information about the state of the Earth’s climate.

       I’ve tried to come up with different ways of visualising this. The four Hiroshima bombs per second (almost five if the imbalance is 0.6 watt/m²) should be well-known by SkS readers, but there are less destructive but still very striking ways this energy could impact us.

       Imagine that all this energy (300 trillion watts in total if 0.6 watt/m²) is focused on melting ice. If the temperature of the ice is -10°C, then heating it to 0°C will require 21 Joule/gram, and then we need additional 334 Joule/gram to melt it, or 355 Joule/gram in total.

       That should translate to 73 gigatons or about 80 cubic kilometres of melted ice every day, or a gigantic ice cube with sides measuring 4.3 kilometres! That ice cube would be almost as tall and have roughly three times the volume of the famous mountain Matterhorn in the Alps. And the flow of melt water from all that ice (845.000 cubic metres per second) would equal the discharge of four Amazon rivers!

       Just an alternative to the four or five Hiroshima bombs! Maybe someone could make an illustration based on this idea?

39332. franklefkin at 09:02 AM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       Tom Curtis,

       Warren had asked about satellite measurements.  You cherry picked UAH instead of RSS.  His (Warren's) question was about 17 years, so he picked the time frame.

        

       Since you dismissed his question by stating it was false, I just pointed out it was actually correct.  You may be (most likely are) correct about the deficeincies of RSS, but the question asked was about the satellite records, not about a highly accurate satellite record.

39333. Tom Curtis at 08:39 AM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       franklefkin @11, it is true that out of all seven global temperature indices you can find one that does not show a positive trend over the last 17 years.  However, the reason it is different is well known.  

       First, satellite measurements, which measure a weighted average of the air temperature from the surface to over 10 km of altitude (with different weights over land and ocean) are more strongly effected by ENSO fluctuations than instrumental records.  There are multiple lines of evidence showing that ENSO fluctations are the major cause of the reduction in the short term global temperature trend.  Being effected more, this means that satellite trends show a greater reduction in that trend.

       Second, the RSS temperature index excludes the high arctic, most of Antarctica, the Himalayas, parts of the Andes and part of Greenland.  The former are excluded because the satellite is never over those positions, while the latter are excluded because their altitude is too great for effective measurement.  The high arctic is one of the most rapidly warming places on Earth, and excluding it also contributes to a reduced trend in RSS.

       So while it is possible to cherry pick one out of seven indices to make a point, it is an obvious cherry pick, and one that exacerbates the cherry pick in using a temperature peak high above trend as a start point for known reasons.  Even so, the RSS indice includes the AR4 predicted trend within its uncertainty range.

39334. Tom Curtis at 08:19 AM on 24 January 2014
       It hasn't warmed since 1998
       

       cpslashm @274, your theory is superficially attractive, but as it turns out the total energy going into ice melt is very small relative to the total energy being absorbed at the Earth's surface due to the enhanced greenhouse effect.  Most (approx 90%) of that excess energy is being absorbed by the ocean.  There is no reason why increased ice melt would draw that energy exclusively from the atmosphere, so it is very unlikely that your theory is correct.

       As it happens, base on a number of different lines of evidence, the major cause of the reduced rate of increase of global surface temperatures has been a switch from El Nino dominated conditions to La Nina conditions.  A further contributor, especially to the reduction in temperature indices that exclude the Arctic, has been a recent pattern of colder winters in mid-northern latitudes and warmer winters in very high latitudes.  Because the warmer high latitude winters are not included in the observations, this shows up as a reduced overall rate of warming.  There is an apparent connection to ice melt in this pattern, in that evidence suggests it is a lack of ice cover on the Arctic ocean causing this pattern.  Finally, some recent volcanoes, an increase in anthropogenic aerosol emissions and reduced solar radiation have also contributed to the reduced short term temperature trend.  

       The exact contribution of each of these factors has not yet been determined.  Indeed, there is some possibility that the combination of these factors explains more than the observed reduction in trend, ie, that the short term temperature trend would have accelerated were it not for this concatenation of factors.

39335. cpslashm at 07:26 AM on 24 January 2014
       It hasn't warmed since 1998
       

       I'm no climate scientist andI like to keep things simple. Some things seem obvious. 

       Take a four-year rolling mean of the global surface temperature data. In the early 2000s it suddenly shoots off to the right. Let's assume the temperature rise has gone on holiday for a while, where did the heat go?

       Take a four-year rolling mean of the PIOMAS annual minimum volume data. From the late 1980s to the early 2000s there's a reasonably linear trend of around -250 km^3 of ice lost per year. From the early 2000s to the present there's a linear trend of around -700km^3 (equivalent to more than 2*10^20J) per year. 

       All that heat is being absorbed in a constant-temperature process (melting ice). The latter trend line hits zero around 2017 (mid rolling year), so the heat will have no-where to go without increasing temperature somewhere. I suspect Arctic (and possibly global) temperatures will rise until the Greenland ice sheet can be pursuaded to lose 700km^3 per year, resulting in another, longer, pause in temperature rise. 

       If the correlation of this amateur spreadsheed graph analysis has validity, we'll find out what happens to global crop production under these new conditions within five years. 

       A graph I found of the global glacial mass anomaly also appears to have a kink, but I lack the original data to play with.

       And no I don't know why a current four-year cycle seems to give a good fit.

       That's my tuppence worth.

39336. Tom Dayton at 07:04 AM on 24 January 2014
       Climate scientist Dessler to US Senate: 'Climate change is a clear and present danger'
       

       And the Rabbett described how Curry argued against herself; either she does not remember or she adjusts her statements of conviction to match her goal.

39337. plg at 06:58 AM on 24 January 2014
       It’s all a Question of Balance
       An idea for a graphic (I do not draw well, but I like visualizing and scribbling on a whiteboard):Imagine two kids sitting on a seesaw, in perfect balance; then one is given a big soda and the seesaw tips over... Now put two very fat men on the seesaw, and hand one of them a soda; the seesaw tips over just in the same way, i.e. the weights do not matter, only the weight difference in absolute terms. (the pressure on the ground is the same in both cases, exactly one soda bottle).Minor quibble: it takes longer for the fat men to reach a new equilibrium, but the end result is the same.
39338. Tom Dayton at 06:56 AM on 24 January 2014
       Climate scientist Dessler to US Senate: 'Climate change is a clear and present danger'
       

       More on Curry's testimony at And Then There's Physics.  And more by John Nielsen-Gammon.

39339. Tom Dayton at 06:52 AM on 24 January 2014
       Climate scientist Dessler to US Senate: 'Climate change is a clear and present danger'
       

       DD, Tamino just posted solid evidence of Curry's disingenuouness in saying we don't know whether sea level rise has accelerated in the past 150 years or so.

39340. scaddenp at 06:50 AM on 24 January 2014
       Global warming theory isn't falsifiable
       

       Much of this idea about "falsfiability" actually comes back to models. Those screaming about lack of proof conveniently ignore all the obvious direct tests made long ago because they dont falsify the theory as hoped. Instead this is an expectation that climate theory will predict tomorrow's weather and bitching because the failure of climate models to do this doesnt seem to count as falsification. It is important to realise that the theory could be right but models could be wrong, but more importantly, models are predicting long term trends (remarkably well) and dont pretend to have any skill at predicting decadal trends.

       Its worth having a look at the papers in "empirical evidence for global warming". The Evans 2006 paper (and similar by Harries, Chen etc) are pretty direct experiments that would have returned different results if AGW was wrong.

39341. michael sweet at 06:22 AM on 24 January 2014
       Global warming theory isn't falsifiable
       

       Jacklongley,

       In 1896 Arhennius predicted that the land would warm faster than the ocean, the Northern Hemisphere faster than the Southern, the night faster than the day, the Arctic faster than the rest of the Northern Hemisphere, and the winter faster than the summer.  If any of the predictions did not work out that might be considered a "falsification" by those who make this argument.  In the 120 years since his predictions, the measured data show he was correct on all of them.  Can you suggest an alternate theory that explains these observations?  Skeptics have provided no alternate thory.  There are myriad other more recent predictions of climate science that can be found, but Arhennius is so strong an argument that it seems not worth the trouble to look them up.  

39342. Tom Dayton at 06:10 AM on 24 January 2014
       Global warming theory isn't falsifiable
       

       Dikran's list is sufficient, but there are several places where folks have discussed in more detail.  One is at Climate Sight.

39343. StBarnabas at 06:08 AM on 24 January 2014
       Tony Eggleton offers an excellent introduction to climate change
       

       John

       looks very good, but a bit expensive. Any discounts for sks contributors? Will try to get my University library to syock a few copies

       Sean

39344. JohnSeers at 06:07 AM on 24 January 2014
       Postma disproved the greenhouse effect
       

        

       Your PDF link:

       "recent attention has recently been going around the web concerning a new “paper” done by Joseph E. Postma (PDF here)"

       is not valid. Please fix.

        

39345. StBarnabas at 05:22 AM on 24 January 2014
       It’s all a Question of Balance
       

       Glenn

       nice article. I would prefer replacing  "The strength of sunlight at the Earth’s orbital distance from the Sun is equal to around 341 Watts for every square meter of the Earth’s surface." With "On average..." Or on average  over a day/year........" I am used to thinking of 1kWm^-2 in sunlight (1.5 ATM) as I so a lot of work on PV, but of course if  you integrate over a sphere etc. Just a thought?

        

39346. Dikran Marsupial at 04:31 AM on 24 January 2014
       Global warming theory isn't falsifiable
       

       P.S. there is a good reason why Google doesn't show much of interest, which is that it anyone who understands falsifiability and the physics of the greenhouse effect can immediately see why it is directly falsifiable.  The question is largely used in the debate for rhetorical, rather than scientific reasons.

       I suspect Tom Curtis would be able to give a very satisfactory answer on this one.

39347. franklefkin at 04:31 AM on 24 January 2014
       Three perfect grade debunkings of climate misinformation
       

       Tom Curtis @10

        

       It is also noteworthy to point out that if you put in the same 1997 start date in RSS, you get a trend of -0.013 +/- 0.201.   So it can be stated that it is flat or even negative!

39348. Dikran Marsupial at 04:30 AM on 24 January 2014
       Global warming theory isn't falsifiable
       

       Falsification just means that it is possible to falsify a theory if it is false.  This means the theory must exclude the possibility of some event.  There is little more to it than that.  In the case of the basic element of AGW is the idea that CO2 is a greenhouse gas, the theory suggest that in the absence of any other change in the forcings that could explain it, a cooling trend on a centennial scale would be impossible while CO2 concontrations continue to rise at a non-negligible rate.  This means that the thoery is falsifiable because there is an observaton (centennial cooling trend) that is excluded by the theory.  Of course there could be quibbling about the length of the trend required and the rate of increase of CO2 etc., but the idea of falsifiability assumes that both parties are acting in a rational and fair manner to determine the exact details of the test.  Hope this helps.

39349. jacklongley at 04:17 AM on 24 January 2014
       Global warming theory isn't falsifiable
       

       As a skeptical person in general, I haven't really made my mind up either way.  But this idea of falsifiability seems particularly elusive.  I've been searching for the current definitions of falsfiability for global climate change theories with little luck.  Is there any resources that summarizes that aspect of the debate?  Google has been no help at all, in that regard.

39350. Philippe Chantreau at 03:27 AM on 24 January 2014
       2014 SkS Weekly Digest #3
       

       I re-read my post #4, I could not find any insult. However, I see how my point could have been missed, so I'll rephrase. 

       I am wondering why anyone would read a blog post by some dude who has no expertise in a subject and immediately think that this dude may be on to something that all the experts of an organ specialized in studying that subject have missed. It is possible, but unlikely enough to trigger high skepticism. A true skeptic attitude would consist of applying, by default, a healthy level of scrutiny toward the accusation from the dude who, by default, should not be given more (or even as much as) credibility than those he accuses.

       When I see instead someone saying what amounts to: looks like NOAA may be messing with us (as this is exactly what Poster initially said in other words), it pretty much sets that person as a pseudo-skeptic. This seems so self evident to me, I don't know how to even explain it. My question to Poster is: Why would Goddard not be subjected to the highest level of scrutiny, even if one doesn't know his dismal history of incompetence? And if one did not do that, why would he be surprised to be poo-pooed when bringing Goddard's garbage here, where due scrutiny has been applied to this kind of nonsense for years.

       Poster is acting all offended, but really, when faced with the reality of what Goddard is and has done, would the appropriate response not be something: "OK, sorry I did not know that this guy was such a joke." That would have been my response.

       I concede that Poster could construe SkS contributor's tone as condescending, but it was not without reason. As far as the overall tone of the site, Watts and McI continuously encourage accusations of fraud and innuendo of all kinds. Watts has encouraged his readers to go harass scientists in person. McI has organized a campaign of harassment through FOI requests that had no precedent, explaining to his readers how to set up straw accounts to send requests from every country on Earth. Curry has tolerated posts recommending the summary execution of climate scientists, under the excuse that it was all in good fun. In comparison, SkS is a haven of sanity and maturity. In fact, to one who has followed this "debate" for years, there is no comparison possible.

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