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Composer99 at 00:15 AM on 24 July 2013Empirical evidence that humans are causing global warming
For instance we have no way of telling whether the increase in temperature 1979 - 2000 is due directly to the rise in human emissions of CO2 or is a negative feedback to the cooling that took place in the 1950’s and 1960’s (possibly long term changes in ocean currents causing changes in cloud cover) or even a negative feedback to the cooling during the LIA.
Where is this idea coming from?
Do you have a cite or is this idle speculation?
Considering we can quantify the radiative forcings, either through direct measurement or by proxy, affecting the Earth's energy balance, and quantify, to a reasonable first approximation, the effects of feedbacks, over the time frame in question (1970s to present) I would have to say that this claim is simply incorrect.
The climate change Clue(do) post, and other posts here, show that we cannot account for the warming of the past 40 years without the enhanced greenhouse effect. On that basis, of course we can tell that "the increase in temperature 1979 - 2000 is due directly to the rise in human emissions of CO2".
There is no way that the extra heat in the oceans can “come back to bite us” as in some kind of sudden rise in temperature caused by heat coming from the oceans.
ENSO would appear to be just such a phenomenon.
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Dikran Marsupial at 00:04 AM on 24 July 2013Empirical evidence that humans are causing global warming
Matthew L wrote "There is no way that the extra heat in the oceans can “come back to bite us” as in some kind of sudden rise in temperature caused by heat coming from the oceans."
This is nonsense. Please can you tell me what is thought to have caused the sudden rise in surface temperatures in 1998?It is also a blatant straw man, the extra heat in the oceans need not cause a sudden rise in temperatures to cause a problem. Equalising over the course of a couple of decades would be bad enough, the point is that thermodynamics tells us that the oceans and atmosphere will equalise at some point.
As to statistical tests, yes, of course such tests are possible (you need to look at the statistical power of the test).
Have you performed or seen demonstrated a statistical test that establishes that there actually has been a hiatus in GMSTs and what we are seeing is not just an artefact of the noise? If not, perhaps you need to ask yourself how you are in a position to question the statistics of mainstream science when you have not subjected your own position to a rigorous test. Do look into this question, it is likely to resolve your niggle.
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Tom Dayton at 23:40 PM on 23 July 2013Empirical evidence that humans are causing global warming
Matthew L, you wrote the oceans "are clearly capable of acting as a huge heat / energy sink and atmospheric temperatures are likely to be almost entirely 'buffered' by the oceans capacity to absorb that heat."
Yes, almost entirely, as you can see from the first figure in this post. So what? The atmospheric temperature portion not buffered is sufficiently large to cause the atmospheric temperature rise from greenhouse gases that we have seen historically and continue to see. You seem to be implying that the amount of buffering will drastically increase starting now... well, now... well, tomorrow...
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JasonB at 23:22 PM on 23 July 20132013 SkS Weekly News Roundup #29B
CBDunkerson,
Yes, I had a bit of a laugh to myself when I realised that their defence was apparently that what they were saying was not meant to be taken as factually true. It's the other kind of "truth".
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MA Rodger at 23:19 PM on 23 July 2013Empirical evidence that humans are causing global warming
Matthew L @99.
Concerning that one recurrent "niggle" of yours; the question of how divergent a 'prediction' may become yet still remain valid. I do wonder if you are overlooking the true cause of your "niggle."
@85 you wrote that there has been "little visible trend (in global average temperature) either up or down for some years." What do you mean by "some years"?
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CBDunkerson at 22:42 PM on 23 July 20132013 SkS Weekly News Roundup #29B
Chriskoz, on the Mann court case... am I understanding the (rejected) argument for dismissal correctly?
It seems like NRO and CEI were arguing that the case should be dismissed because they were only expressing their opinions with "rhetorical hyperbole" rather than meaning to suggest to anyone that Mann had actually committed "fraud" in a legal sense.
If so, that ridiculous lie, which ought to qualify as perjury IMO, seems like a bigger story than the dismissal itself. I'd love to see them explain to all their 'skeptic' followers how they were not saying that it was a fact that Mann committed a crime... the readers all just 'misinterpreted' them. This kind of 'treason to the cause' from 'heros' of a movement is often the only thing which can penetrate the sort of deep denial underlying climate change 'skepticism'.
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jsam at 22:26 PM on 23 July 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Waterloo alumni aren't all that impressed.
Moderator Response:[RH] Hotlinked URL that was breaking page formatting.
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Matthew L at 22:14 PM on 23 July 2013Empirical evidence that humans are causing global warming
“We know from physics theory and lab experiment that adding greenhouse gases to the atmosphere must cause warming (or at least be counteracted by cooling forcings such as reduced solar irradiance or increased concentration of reflective aerosols).”
We know from physics that, all other things being equal and in the absence of feedbacks, that adding extra CO2 to the atmosphere must cause warming.
But of course all things are never equal in a dynamic, chaotic, system such as the Earth’s atmosphere and oceans. There are feedbacks both positive and negative and the deep ocean is capable of absorbing mind bogglingly huge amounts of “excess heat” without rising very much in either temperature or height. If the deep oceans absorb that heat and barely rise in temperature then they cannot heat the atmosphere by any more than they have risen in temperature themselves (an ocean at a temperature of, say, 14c cannot heat the atmosphere to a temperature any higher than 14c) so if the deep oceans really are capable of absorbing most of the excess heat from the last 10 – 15 years as Trenberth and others have hypothesised, then they are clearly capable of acting as a huge heat / energy sink and atmospheric temperatures are likely to be almost entirely “buffered” by the oceans capacity to absorb that heat.
There is no way that the extra heat in the oceans can “come back to bite us” as in some kind of sudden rise in temperature caused by heat coming from the oceans. The oceans may vary in the amount of heat they absorb at various points in time but how much and over what time periods clearly nobody knows or we would have been able to predict the current hiatus in the warming.
“We know by process of elimination that the current global warming must be the result of an enhanced greenhouse effect: no other phenomenon we can observe can account for the behaviour of the Earth climate system.”
Well as you state earlier in your post, the greenhouse effect is what keeps our climate warm. However, the tiny changes in temperature trends we have seen over the last few decades are well within the magnitude of natural variation and/or possible feedbacks to earlier changes in temperature.
For instance we have no way of telling whether the increase in temperature 1979 - 2000 is due directly to the rise in human emissions of CO2 or is a negative feedback to the cooling that took place in the 1950’s and 1960’s (possibly long term changes in ocean currents causing changes in cloud cover) or even a negative feedback to the cooling during the LIA.
“We know, also by process of elimination and by other supporting observations (e.g. declining O2 content in atmosphere), that the only source of greenhouse gases sufficient to account for the observed increase is from human combustion of fossil fuels.”
As stated in my prior comment I do not argue with that. There is no need to rebut arguments I have not made.
Generally my problem with the current climate models is that they do not appear to account sufficiently for natural variability, either in magnitude or duration (particularly in the deep oceans’ ability to absorb heat), nor do they envisage that there can be long-acting negative feedbacks such as long acting changes in cloud cover caused by changes in wind patterns and ocean circulation.
The one niggle in all this that keeps coming back is the question “How far and for how long does the actual temperature record have to diverge from the predictions of the models before the models are falsified?”. This seems to be a continually moving goal post. 15 years ago it was 10 years. 5 years ago it was 15 years and now it seems to be 20+ years. Is there any statistical test? Maybe that is one for Grant Foster!
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Tom Curtis at 21:31 PM on 23 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
Richard Lawson @14, climate sensitivity does vary based on temperature and arrangement of continents (and probably other factors as well). However, across the very broad range of conditions that have existed for the last 500 million years, climate sensitivities of 3-4 C have been a consistent feature. Further, high end climate sensitivities have been associated with both very warm and very cold conditions in the past.
So, we may have lucked out into an era of unusually low climate sensitivity (although the continental arrangement suggests otherwise), but the odds are against it. Further, even if we have, there will be a temperature threshold which, if we pass, will result in a greater climate sensitivity. If that threshold is within the range of temperatures we will reach with global warming and a low climate sensitivity, the result will be warming consistent with a high climate sensitivity, but with a slow initial warming lulling us into a false sense of security.
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CBDunkerson at 21:23 PM on 23 July 2013Why doesn’t the temperature rise at the same rate that CO2 increases?
DAK4Blizzard, Glenn directly covered most of your questions and the fact that ARGO buoys have a maximum depth of 2000 meters should explain why data below that point isn't included. There is no 'lack of interaction' in the deeper oceans, and indeed various studies of deep ocean temperatures have found evidence that significant additional warming is accumulating there. We just don't have widespread or continuous readings for those depths, and thus estimates of total additional heat accumulation in the deep ocean have a wide uncertainty range.
Thus, the chart in the article above is 'conservative' in excluding the deep ocean heat content change... but only because the data on that isn't available at the same level of detail as the other items shown.
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Tom Curtis at 21:23 PM on 23 July 20132013 SkS Weekly News Roundup #29B
JvD, I will note that I am also dubious about the claims regarding fossil fuel subsidies. That, however, is because such claims rarely consider fossil fuel explicit taxes (ie, taxes in excess of those that apply for normal business activity or resource acquisition). Further, they sometimes count as subsidies tax exemptions of "fuel taxes" from fuel taxes. When a tax on fuel use is implemented, but some people are exempt, that represents a reduction of the net tax rate, not a subsidy.
However, the claiming that consumption subsidies are not subsidies is simply incorrect.
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Richard Lawson at 21:14 PM on 23 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
Apologies if this is a naive question, but could it not be that CS has a different value depending on the prevailing conditions?
Global temperatures seem to have been pretty unstable during the ice ages, and rather more stable in the interglacials. CS figures derived from paleolithic cold conditions may be accurate in regard to those states of the planet, but not relevant to modern conditions. The previous three interglacials maxed out consistently at a couple of degrees Celsius warmer than present times, so there does seem to be a natural upper limit of planetary temperature, in the absence of the kind of GHG changes that we have unfortunately brought about.
So my question is - could it be that the high "tail" of GHG values (that is, higher than 4.5C) is not due to any errors of climate science, but simply represent values that are not relevant to our stage in the cycle?
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Tom Curtis at 21:14 PM on 23 July 20132013 SkS Weekly News Roundup #29B
JvD @11, as I understand it, the subsidies in Saudi Arabia are paid for by a reduction in the revenue paid to the government by the oil companies. That being the case, this is a distinction that makes it illegitimate to extend the metaphore as you have done. It is illigitmate because the cost of the subsidy in the GM case is either born by its other customers in terms of increased prices, or by the shareholders in terms of reduced profits (or some combination of the two). In the Saudi case, as I understand it, however, the costs are born by a third party.
Because the revenue is lost to the government, it would make perfect sense for a minister of the government to question whether it was an appropriate expenditure of public money. They might decide Saudi Arabia would be better of if its citizens paid the normal commerical price for oil, and the extra revenue was diverted to building hospitals (for example). Such a decision would be perfectly legitimate, and would be described as funding improved public health by eliminating a subsidy on private transport.
I know that is how it would be described, because that is exactly the sort of terms used by the Saudi Minister of Economy and Planning in the link KR provided:
' "This has become an increasingly important issue as these subsidies have become increasingly distorting to our economy. This is something we are trying to address," Economy and Planning Minister Mohammed al-Jasser said on Tuesday.
"Rationalisation of subsidies, particularly on fuels for non-targeted participants", is needed to improve Saudi productivity, he told a financial conference in Riyadh.'
If it is appropriate to describe it as a subsidy when discussing alternative used for the funds, such as building hospitals (my fictional example), of providing for more extensive low income welfare (an example actually proposed); then it does not cease to be rational to so describe it when we are talking about the impact on renewable energy.
It would certainly be reasonable for a company wanting to invest in solar power to approach the Saudi government on the basis that the subsidy makes solar power uneconomic in Saudi Arabia; but that if the subsidy was eliminated, solar power would be economic and provide a significant part of Saudi Arabia's energy needs, and preserving more of its oil for sale at commerical rates. They could even make the case that doing so would provide a net economic benefit for Saudi Arabia*.
If you want that in a metaphore, an external company could quite appropriately approach GM saying that its employee subsidy was a poor use of funds, and that eliminating it would allow investment in a new production process, greatly increasing GM's overall profitability. If faced with that proposal, a GM board member rejected it because "the employee discount is not a subsidee" their position on the board would be very tenuous on the grounds of incompetence.
*Given Saudi Arabia's low latitude location and desert climate, such a case would almost certainly be correct.
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Glenn Tamblyn at 17:56 PM on 23 July 2013Why doesn’t the temperature rise at the same rate that CO2 increases?
DAK4Blizzard
The difference between 700m and 2000m is historical. It is based on an earlier sensor technology and a later one. Prior to the 2000's, detailed measurement of heat content down to 700 meters was obtained using data from Expendable Bathythermographs. 700 meters was their maximum operating depth. Heat content below 700 was estimated from their data and other more sporadic deep sampling techniques.
In the early 2000's, deployment of the ARGO array of smart robot diving buoys was commenced. These now drift around the oceans, diving to operating depth, sampling the water, surfacing and relaying their data back to satellites. And their maximum operating depth is 2000 meters.
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JvD at 17:51 PM on 23 July 20132013 SkS Weekly News Roundup #29B
What Tesla motors should do, in the above analogy, is try to find ways to produce its cars for less. It should aim to reduce costs to less than $100 per car! *Or* it should apply for a subsidy from the state (and actual subsidy in the normal sense of the word!)
But for Tesla Motors to instead complain about the so-called 'subsidy' that GM is 'ploughing into' its program to sell cars at cost to its own employees is simply crazy! The one thing has *nothing* to do with the other? It is misinformation! It is incredible that people swallow this nonsense!
(-snip-).
Moderator Response:[DB] Inflammatory snipped.
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JvD at 17:25 PM on 23 July 20132013 SkS Weekly News Roundup #29B
@Tom, I think you are missing the point. I'll expand on your analogy of GM.
Let's say GM produces cars for $15 a piece, and sells them for $100. However, to it's own employees, it sells them for $15. Now, a competitor of GM - lets call it Tesla Motor - comes in to the market selling cars that cost$200 dollars to make, which it sells for $210.
Would it be right for Tesla Motors to say: "Hey, not fair! GM is subsidising its cars! GM should not do this, but it should instead use that cash which it is ploughing into subsidising its cars in order to help us sell our cars! If we would get this subsidy, then we would be able to compete with GM cars better!"
See what I mean? This is a utterly misleading. It is false. Is that clear now? Please tell me it is. It is not a difficult question, I think.
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Tom Curtis at 16:40 PM on 23 July 20132013 SkS Weekly News Roundup #29B
JvD @9, if a corporation sold part of its product to employees at cost, there would be no doubt that it was a financial benefit for the employees. In accounting for the cost of that financial benefit, the cost assessed would be the difference between the sale price to employees and the normal sale price, that being the loss in profits.
If you disagree, by all means recommend to GM that they sell cars to US citizens at the cost of manufacture. You can assure them with a straight face (which I couldn't) that that would not represent a subsidy and hence would cost them nothing.
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JvD at 16:20 PM on 23 July 20132013 SkS Weekly News Roundup #29B
Now hold on a minute. Let's say oil costs on average $15 to get out of the ground and into people's cars in Saudi Arabia. That's about right. Now, Saudi Arabia could sell that oil on the international market for $100, so that $85 dollar difference is now chalked up as a "subsidy"?!? That is how most of the "600 billion dollar" figure came about in the following text under the article above:
Diverting cash used to subsidise fossil fuel production and consumption could raise up to $600 billion a year to fund cuts in greenhouse gas emissions and help poor countries adapt to the effect of a warmer planet, delegates at U.N. talks were told in the Philippines this week.
Industrialised nations plough $600 billion a year to subside coal, oil and gas activity.
Surely. Surely you guys agree that this is incredibly misleading? It seems to obvious. If it is not clear, please read the joint IEA/OECD/OPEC/World Bank report I linked to above, because it explains it better.
Note that there is no 'cash' used for this subsidy. Countries like Saudi Arabia are merely selling one part of their oil on the international market, and another part of their oil to domestic consumers at cost. This is not a subsidy!
Let's put it another way. Lets say my country produces a lot of potato's which it can sell at ten times the cost on the international market. However, the farmers don't pay that international price when they consume a potato themselves, but they only pay the cost to produce the potato's. Is that a subsidy? No, of course not! Surely, that is clear? (Please if anybody is reading this, help me out here, I don't know how to explain this better, but it is a very important issue.)
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DAK4Blizzard at 14:49 PM on 23 July 2013Why doesn’t the temperature rise at the same rate that CO2 increases?
Why exactly is the ocean depth of 700 meters to 2000 meters used? Why is it 700 meters (rather than say 500 or 1000), and why not include the ocean below 2000 meters? Does the deeper ocean not interact as much/directly?
@mandas: The forcings that dictate weather trends may be different, occur on a different scale, and occur in a shorter period from those that influence climate trends. It's an interesting point you make, and it's true that global termperature has not been increasing at a steady linear rate in short runs. But I think the analogy may be too weak to be substituted as a point on climate for longer runs.
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mandas at 13:21 PM on 23 July 2013Why doesn’t the temperature rise at the same rate that CO2 increases?
I have an analogy for this, and I would like everyone's opinion on whether or not it is valid.
Today is the 23rd July, which means it is 32 days past the solstice, and the level of solar radiative forcing has been increasing (here in Australia) every day over the last month. Yet interestingly, the temperature hasn't been increasing every day at the same rate. The temperature has been going up and down, and it will continue to go up and down in response to other forcings. Yet, over the next 6 months or so, the long term temperature trend will be upwards in response to the solar forcing.
We don't expect the temperature to increase at a linear rate every day from winter to summer, why would we expect temperature to do the same in response to CO2 forcing?
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KR at 10:22 AM on 23 July 20132013 SkS Weekly News Roundup #29B
JvD - Consumption subsidies are indeed still subsidies; artificially reducing prices by diverting monies from elsewhere in a fashion which encourages consumption. Also note that there are probably another 300-400 B in 'hidden' subsidies such as tax structuring in developed and developing countries, rather more difficult to directly pull out but still there.
"Those countries are merely selling their own citizens fuel at the cost of production." - That would be incorrect; Saudi Arabia, for example, subsidizes fuels for its people out of foreign sales, to the extent of risking their own economy. This encourages massive over-consumption, they consume more per capita than the US and more total than the UK, despite having half the population.
Again, fossil fuel subsidies are not, as you claim, a myth. They are real, they encourage fossil fuel consumption by artificial price supression, and they distort economies.
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bvee at 09:56 AM on 23 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
i'm not criticising the style - ie line weight and title. although i do like the hue of blue used.
i am saying the graph indicates that models are insensitive to climate sensitivity.
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scaddenp at 09:56 AM on 23 July 20132013 SkS Weekly News Roundup #29B
Huh? In my books, where a government pays money to a producer so that the consumer cost is less than market rate, that is a subsidy. They are not paying market rate and therefore it distorts comparison with other fuel sources. Now, for many places, unsubsidized fossil fuel may well be cheaper than unsubsized other sources (Not here in NZ), but while governments provide market-price distorting subsidies in various ways, you cannot know. Ask the question - if the government stopped paying those monies, would the consumer cost go up? If yes, then its a subsidy.
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JvD at 09:39 AM on 23 July 20132013 SkS Weekly News Roundup #29B
KR, consumption subsidies in oil producing countries are not really subsidies. Those countries are merely selling their own citizens fuel at the cost of production.
It makes no sense to lump such 'consumption subsidies' into the same category with actual production subsidies in OECD nations to solar and wind owners. These are completely different things!
It muddles the discussion. It decieves people into thinking that solar and wind energy are competitive wth fossil fuels. This doesn't help. True environmentalists should explain to the public that fossil fuels are incredibly cheap, while solar and wind are expensive. What that means is that people will have to *pay* to increase solar and wind energy. It is no use trying to trick people into thinking that some dumb misinformation like "600B fossil fuel subsidies" is what is holding solar and wind back. It's just nonsense and it should stop. Don't you think?
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Tom Curtis at 09:17 AM on 23 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
ianw01, chriskoz, bvee:
1) The graph displays 7.4 pixels per century as measured on Paint.
2) The low climate sensitivity mark is displaced by four pixels relative to the high climate sensitivity mark, whereas logically they should by on the same point on the x-axis.
3) Displaying the three possible outcomes shown seperately would merely cause an indistinguishable wedge, removing clarity. I do not see how the loss of clarity and visual simplicity would be compensated by so small a gain in logical coherence.
4) We can take the red line to be the modelled result for historical and projected forcings with a high climate sensitivity with RCP 6.0 The modelled temperatures in such a case would not differ from oberved temperatures by more than the value of half a pixel, and so would be indistinguishable. The low and modal values would properly be indicated by a line across from the right y-axis in that case. So considered, the criticisms of the graph come down to one of style. This shows them to be entirely trivial.
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bvee at 08:29 AM on 23 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
and why does the graph combine measured and projected into one color?
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bvee at 08:27 AM on 23 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
ianw01 is right - the graph is wrong
and it's closer to 10px/100 yrs
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ianw01 at 07:29 AM on 23 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
chriskoz@8: I'm not quite following you, but let me try:
The article says the figure shows "the amount of warming we can expect .... for equilibrium climate sensitivities of 1.5°C (best case), 3°C (most likely), and 4.5°C (worst case)"
If I take your response, that the dots do have different x-values, then the clear (but steep) slope between the points indicates that in addition to the different amounts of warming, it will take longer to reach the peak for each climate sensitivity?
If I have it right now, I'd argue for a short dotted tail branching out to the right of each dot indicating that there are alternate trajectories for each sensitivity.
The unsettling aspect is that it seems to portray in inevitable climb past the "low sensitivity" red dot, no matter what. I don't want to beat this issue to death, but this logical inconsistency undermines the credibility of the graphic.
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william5331 at 06:39 AM on 23 July 20132013 SkS Weekly Digest #29
There seems to be a feeling that the so called developed world; the rich countries will be able to buy their way out of the results of climate change. One could argue the converse. Think of the East Coast of America. A megalopolus from the Canadian border down to Florida. Massive cities with, at most, three days of food within their borders and dependent on food delivered from the hinterland (the whole of the US of A and even the world) at a rate which is just eneough and just in time. This megalopolus is also totally dependent on systems which bring in fresh water and take away and treat sewage. Now have a complete failure of the wheat, soya, barley, corn and vegetable crop in the US of A rather than the little glitches we have seen over the past few years. Have a few Sandies but ones large enough to effect the power lines, sources of fresh water and so forth. I think I would rather be in some remote area with my own vegetable gardens and close to a hinterland where I could hunt a rabbit from time to time.
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Composer99 at 05:20 AM on 23 July 2013Empirical evidence that humans are causing global warming
Matthew L:
You'll have to put up with some asperity from me, but trying to argue
My contention is that warming itself cannot directly be linked to human causation only indirectly if one assumes that all warming is due to the increase in CO2.
Yes, CO2 has increased caused by human emissions and yes, over the last century there has been warming. However, correlation is not proof of causation.
in 2013 is like trying to argue against the germ theory of disease.
- The link I have you systematically ruled out any agent, other than anthropogenic greenhouse gas emissions, as the primary cause of warming in the 20th century and hence, especially since 1970.
- CO2 was demonstrated in the mid-19th century to be a confirmed greenhouse gas, and its relation to warming the planet was first elucidated by Svante Arrhenius at the turn of the 19th/20th centuries. The physical mechanisms behind CO2 absorption of infrared and the greenhouse effect were made clear with the development of quantum mechanics, and with the study of the upper atmosphere during the early part of the Cold War.
Thus:
- We know from physics theory and lab experiment that adding greenhouse gases to the atmosphere must, cause warming (or at least be counteracted by cooling forcings such as reduced solar irradiance or increased concentration of reflective aerosols).
- We know by process of elimination that the current global warming must be the result of an enhanced greenhouse effect: no other phenomenon we can observe can account for the behaviour of the Earth climate system. See, for example, the summary of radiative forcings since the pre-industrial era in the IPCC AR4, WG1.
- We know, also by process of elimination and by other supporting observations (e.g. declining O2 content in atmosphere), that the only source of greenhouse gases sufficient to account for the observed increase is from human combustion of fossil fuels.
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Chris G at 02:52 AM on 23 July 2013Why doesn’t the temperature rise at the same rate that CO2 increases?
Thanks; this will be useful, for those who actually seek to understand at least.
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Dikran Marsupial at 01:33 AM on 23 July 2013Empirical evidence that humans are causing global warming
Matthew L wrote "The global average surface (and Troposphere) temperature is currently pretty stable year to year within a ~ +/- 0.5c range up and down and has been for at least 10 years (depending on the data set)."
Given that the projected rise in GMST for the two decades following the last IPCC report was 0.2c per decade, stating that temperatures are stable to within +/- 0.5c for at least 10 years is pretty much what you would expect if the projection were correct!
I have to say I get a bit tetchy when people write "correlation is not proof of causation" in conjunction with GMSTs and AGW. It is as if this correllation were mainstream sciences only source of evidence regarding the causal relationship, essentially ignoring a couple of centuries of physics and a multitude of other lines of evidence (e.g. OHC).
We also wouldn't expect to see a good correlation over a period of a decade as CO2 is not the only forcing, and as well as forcings, GMSTs are also affected by internal climate variability (e.g. things such as ENSO). This means it is a bit of a red-herring anyway! -
Philippe Chantreau at 01:23 AM on 23 July 2013Empirical evidence that humans are causing global warming
And the same could be said of numerous 10 years periods in the historical record, even the trend is what it is. Matthew is going down the up escalator, and ignoring that there is a very clear and inescapable physical mechanism for warming from increased atmospheric CO2. Same old...
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Matthew L at 00:47 AM on 23 July 2013Empirical evidence that humans are causing global warming
Moderator: I think the following is on-topic. My second post was written before I saw your first post directing me to other threads, so my apologies if it seemed off topic.
Composer99
"There are multiple lines of evidence showing that the enhanced greenhouse effect causing the present warming is itself human-caused, as well as evidence excluding other sources. These lines of evidence are discussed here (and elsewhere) on Skeptical Science (and from thence the primary literature)."
Your link under the word "here" is to an article on the fact that the increase in CO2 in the atmosphere is "human-caused". That is something well proven and I do not argue with. My contention is that warming itself cannot directly be linked to human causation only indirectly if one assumes that all warming is due to the increase in CO2.
Yes, CO2 has increased caused by human emissions and yes, over the last century there has been warming. However, correlation is not proof of causation.
The global average surface (and Troposphere) temperature is currently pretty stable year to year within a ~ +/- 0.5c range up and down and has been for at least 10 years (depending on the data set). At some point the correlation will break down as the models' predicted increase in temperature moves further and further away from the actual measured temperature.
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KR at 23:56 PM on 22 July 20132013 SkS Weekly News Roundup #29B
JvD - I fear you are looking at only a subset of the numbers. OECD countries are hardly the only group involved, and much of the subsidies are consumption subsidies in exporting countries, such as Iran and Saudia Arabia.
Duncan Clark in the Guardian has a good breakdown on a country-by-country basis, which is also worth looking at. Fossil fuel subsidies are not a myth. And phasing those subsidies out would have an impressive impact on emissions, estimated reductions (for example) on the order of 2.6 B tonnes by 2035, or ~70% of current EU emissions.
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JvD at 23:19 PM on 22 July 20132013 SkS Weekly News Roundup #29B
"Industrialised nations plough $600 billion a year to subside coal, oil and gas activity."
This is not true! OECD countries 'plough' only about $45 to $75 billion of subsidies into fossil fuels per year, and they reap about $800 billion in tax revenues from the fossil fuel sector, of which about $400 billion directly from fuel taxes and another $400 billion from VAT and goods and services taxes.
http://www.oecd.org/site/tadffss/49006998.pdf
(-snip-).
Moderator Response:[DB] Inflammatory tone snipped.
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Glenn Tamblyn at 19:03 PM on 22 July 2013Carbon Dioxide's invisibility is what causes global warming
gingcckgo, re Abbott's Dog Whistle.
Absolutely. The problem for Abbott is that a majority of the rest of the population don't agree with him on this and the dog whistle isn't silent for them, it is a horrible screeching in their ear. If he appeals to his rabid base, he alienates his broader or swinging base.
Something to do with petards and hoisting...
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ginckgo at 15:27 PM on 22 July 2013Carbon Dioxide's invisibility is what causes global warming
You miss the point of this little Abbott dog-whistle, it's a cleverly coded message to his lunatic support base: http://www.abc.net.au/news/2013-07-18/green-an-invisible-nod-to-the-climate-change-sceptics/4826472
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chriskoz at 14:17 PM on 22 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
ianw01@7, you said:
Do the 3 labeled points have different x values? Presumably not
You're incorrect. Look at the timescale, draw the other X values of your interest and you'll see that, although 2000 and 2100 are different, their diffference on that plot is ~ one pixel.
I diagree with you that the inset is required to show what's happening between 2000-2100 because I see that graph as the summary of what was happening in the Holocene (human civilisation time), and the red line indicates the end of Holocene as we know it (some call this new period Anthropocene), there is no need to obstruct this simple picture with the "squeezed to timescale" AR5 scenarios picture refered to earlier, that lead to the red line.
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tamikenn57 at 02:24 AM on 22 July 20132013 SkS Weekly News Roundup #29B
I don't count the increase of natural gas development as the tradeoff for coal reduction in China as a win. Obama is dead set pushing natural gas because of the economic benefits. To include increased exploration that extends the global climate carbon available to the number McKibben puts here: http://www.rollingstone.com/politics/news/global-warmings-terrifying-new-math-20120719
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ianw01 at 23:03 PM on 21 July 2013The Economist Screws Up on the Draft IPCC AR5 Report and Climate Sensitivity
I find the plot quite puzzling. Do the 3 labeled points have different x values? Presumably not; I assume there are 3 overlapping lines that look like one line. For clarity I suggest that thinner lines of different colors be used, or perhaps an inset that shows what is happening in that thin slice of time.
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michael sweet at 21:02 PM on 21 July 20132013 SkS Weekly News Roundup #29B
Chris,
This is terrific news. Thank you for the link. It will be interesting to see how this turns out.
Once again Michael Mann is a trend setter!
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chriskoz at 19:37 PM on 21 July 20132013 SkS Weekly News Roundup #29B
The biggest news (perhaps the biggest in the history of climate science denial so far) is DC court decision to proceed with Michael Mann vs National Review case which might have broken right after this summary.
Interestingly, I scanned carefully through the comments section looking for any denialati innuendo, otherwise always present under news or quote related to Mike Mann. This time a total silence. Someone made a joke that "deniers are now going to say this DC court is part of the 'global conspiracy'", but that would be self-killing move so it looks like they prefer to stay silent. A turning point? Let's hold our breath until the final decision comes...
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MA Rodger at 17:35 PM on 21 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
KK Tung @ 195 & @196.
The question I posed @193 was "Could you thus explain why this wobble is present in the residuals and why its presence has remained unreported?"
You appear to agree @195 that the wobble is significant in that @195 you mention such phenomenon without disputing its existence within my graph @193.
But you say I am not graphing the residuals from T&Zh13 Fig 5 because that would require the subtraction of a linear function while I subtracted the QCO2(t) function. Yet I do not consider such detail relevant to my enquiry. If the subtraction is linear or QCO2(t), neither will make wobbles magically disappear.
@196 you suggest the inset at Fig 3 in your 1st SkS post usefully shows residuals. Let us examine these residuals as there can be no dispute that they are the actual residuals. In that 1st SkS post you describe these residuals in the inset as "Except for s a minor negative trend in the last decade in the Residual, it is almost just noise," but this is not correct.The residuals in Fig3 inset contains a wobble, a signal almost half the size of the original HadCRUT4 signal. This is illustrated in the attached graph where the residuals have been multipled by 2 to show how close they are to being half the size of the original HadCRUT4 signal.A similar sized wobble is also present in the residuals of both the analyses graphed in Zh&T13 Fig 1 and T&Zh13 Fig 5. And the presence of such a wobble is important. After all, the final word of Zh&T13 was "Whether this method is successful can be judged by the reduced scatter in the adjusted data and by the residual’s resemblance to random noise."
So I repeat my question posed @193Could you thus explain why this wobble is present in the residuals and why its presence has remained unreported?
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KK Tung at 09:55 AM on 21 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Continued from post 195, the residual that you were looking for from the MLR analysis using QCO2 as the anthropogenic regressor was shown in Figure 3 in part 1 of my original post. No need to reconstruct.
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whdaffer at 05:40 AM on 21 July 2013It hasn't warmed since 1998
Hi; On the issue of the video being private. Any ETA on when the updated versin will become available? It's a really nice explanation and I'd love to pass it along to some friends for whom such visual representations are more compelling.
whd
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KK Tung at 04:10 AM on 21 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to MA Rodger at post 193:Ahh, I think I now understand your question. Figure 5B is the result of an MLR process, using a linear anthropogenic regressor. You wish to look at the residual of that MLR process, which was not shown in our PNAS paper. So you tried to reconstruct it by subtracting a posteri, an anthropogenic index QCO2, from a different set of MLR discussed in part 1 of my post, and found some significant wobbles. In that post I was trying to demonstrate the robustness of the adjusted data, which I said should ideally consist of anthropogenic response and climate noise, using very different anthropogenic regressors. It then follows that the residual---"climate noise"--- is compensating for the different anthropogenic regressor used. Therefore one cannot find out what the residual of one MLR is by subtracting out a different regressor. The QCO2 regressor was used only in part 1 off my post and a linear regressor was used in Figure 5 of our PNAS paper. I hope this answers your question.
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MA Rodger at 02:23 AM on 21 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
KK Tung.
With no reply from you to my questioning @193, I will assume that the comments @190 & @192 constitutes such a reply. While I take a little time to consider the full implications of those replies, I will present another aspect of the data graphed @193 which also requires some explanation. (And be advised that this is not the last of my enquiries about this data.)The trace of the AMO signal shown in the graph @193 is obtained by subtracting the data presented in T&Zh13 Fig 5a from that in Fig 5b. This AMO signal raises two questions.
Firstly, this AMO signal used in your MLR is smoothed using LOWESS (as described in Zh&T13). This smoothing will smooth out inter-annual wobbles of ENSO or Sol or Vol that are present in the Enfield AMO data series. But such smoothing will not entirely remove ENSO, Sol & Vol. Indeed parts of these signals are still evident in your LOWESS smoothed AMO series. For instance, the inflection in the AMO signal 1980-90 is entirely the residual of two Volcanic wobbles (El Chi'chon & Pinatuba). Surely if AMO is to be used as a regressor then this LOWESS smoothing is allowing a smoothed and still significant ENSO, Sol & Vol signal to remain within that AMO signal. Can this be appropriate? Would it not be better to use, perhaps, MLR to remove ENSO, Sol & Vol from AMO prior to AMO's use in the HadCRUT4 MLR?
Secondly, there appears to be a problem with the more recent end of your smoothed AMO signal. I present the graph below by way of illustration. LOWESS smoothing of the AMO signal allows the signal to be smoothed to the very ends of the data.
The AMO signal has, of course, two ends. The 1856 end remains very flat despite the AMO index for 1856 averaging for more than a year 0.15 above your end-smoothed value. As a product of the smoothing process I have no problem with the flat 1856 end. Where things start to look awry is when this 1856 smoothing is compared with the smoothing at the 2000s end of the series.
The smoothed AMO signal from T&ZH13 Fig5 drops to its end 2007-2011 by 0.053. This is a considerable drop. In size it is over one sixth of the smoothed AMO's full value range. And it is crammed into a 4-year period. It is therefore a big drop.
This is all the more suprising as this drop is well over twice the drop of the smoothed AMO signal used in Zh&T13 Fig1 yet the inset in Zh&T13 clearly shows that Enfield AMO data to at least November 2011 has been used in Zh&T13. How then can T&Zh13 drop so much more than Zh&T13? In T&Zh13 the MLR does extend a further year to 2011 but, even if T&Zh13 included more recent data, any such extra data that is lower valued than your smoothed value (5 months worth) is far less significant than the 13 months-worth from 1856 that makes zero impact on the 1856 end. And, of course, the last year of Enfield AMO (some of which will post-date T&Zh13) is entirely above your smoothed value. As of now, there is no drop whatever!!
So can the large 2007-11 smoothed AMO drop used by T&Zh13 be explained?
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funglestrumpet at 22:42 PM on 20 July 2013Carbon Dioxide's invisibility is what causes global warming
Glenn Tamblyn @ 24
Thank you for taking the trouble to assist me in understanding the phenomenon of global warming in more detail. I imagine that others will have puzzled over the exact mechanism that greenhouse gasses employ in relation to IR radiation; I hope that they have been following the comments section of this post.
Thanks again to all who have commented in reply to my original request!
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chriskoz at 20:22 PM on 20 July 2013Science does inform policy making … sometimes
Good info. The only question I have is the long-term lifetime of HFC in the athmosphere - are they as stable as CO2 or can they decompose faster?
It is important question, because if they maintain a signifficant residual forcing out of that ~0.5Wm-2 forcing shown on Figure2 for many centuries, then they will amplify CO2 impact at eqilibrium. The resulting fraction of a degree may make a lot of difference on top of CO2 induced warming with respect to Earth system tipping points. Consequently, their immediate reduction is as urgent as the reduction of CO2.
Figure 3 gives me an idea what may happen until 2100, but I'm interested in equilibrium conditions beyond 2100, with an optimistic assumption the emissions drop to zero within 2050 as with the white lines on Figure2.
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