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Sober up: world running out of time to keep planet from over-heating
Camburn - "The weather in the US is not the result of AGW. At least that is what the experts tell us. Documentation that the highs are outnumbering the lows in the USA please?" Well, you could look at Record high temperatures versus record lows:
Figure 2: observations of the ratio of record highs to record lows each year (dots), solid line is a smoothed curve fit.
The ratio increase towards and over 2.0 clearly illustrates this point. Your assertions, unfortunately, continue to be unsupportable.
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Bob Lacatena at 15:48 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
22, Camburn, Have you considered that both climate change and increasing competition for dwindling fossil fuel resources is putting the U.S. on a collision course with complete melt down? That the economic and military and moral standing of the U.S.A. is at stake, simply for the sake of short-sighted, selfish thinking? Why in the world wouldn't and shouldn't the U.S.A. wean itself from dependence on fossil fuels, and so secure its own long term independence and prosperity? -
actually thoughtful at 15:47 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Sphaerica - I grant you the point that the trees are turning later (much later). But the skipping the yellows and reds bits, as I recall, is due to how quickly the frosts come, the amount of sugar in the tree and other not-directly-climate-change issues. Or can you educate me about how it ties in? -
Camburn at 15:46 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Spaerica: The 50% pertains to President Obama's approval rating. The last poll about climate that I remember had 53% of Americans concerned, but as part of that poll they asked to rate other concerns and climate did not make the top 20. -
Bob Lacatena at 15:46 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
22, Camburn, Please produce your opinion polls/statistics. You need to support your assertions. Also, politics is open for discussion as far as climate change and energy solutions only. It's not open season. -
Camburn at 15:43 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
skywatcher@17: I have posted links to NOAA Climate Slueths on this site. The weather in the US is not the result of AGW. At least that is what the experts tell us. Documentation that the highs are outnumbering the lows in the USA please? With statistical signifance as well. Thank you. actually thoughtful@18: Being we can discuss politics, and I am from the USA, real clear politics has ongoing polling data. It is what it is. I think the USA is in exaustion mode and I don't like that. Our debt is rising so fast that it is akin to Greece. The trajectory of the graph of debt to GDP is not substainable. People recognize this economic reality and it creates uncertainty. When you add one more uncertainty, climate, to the multitude that are presently here, and it is a future uncertainty, people will put that on the back burner. Yahoo news had a blurb about the protests in Washington today. Read the comments, they are informative of the mood. Yes, over-fishing is just one problem of the ocean. But the fast change in PH is an immediate problem and the science is very cut and dried with high certainty. That makes it an easy sell to most people. -
actually thoughtful at 15:42 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Too bad about the La Nina vs. El Nino. An El Nino in an election year would put the issue front and center. I believe we will see record temperatures, even with a La Nina. But the El Ninos in the US tend to put impressive weather on display. I for one would love to see the Republicans argue that global warming is not happening as they campaign (spin) during the extremes of an El Nino summer. That would put the issue front and center, and force Republicans to address the issue. -
Bob Lacatena at 15:38 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Separately... I don't know if anyone is actually measuring things from year to year, but... it is now November 6 and a lot of trees here (Massachusetts) are still green. By now more than half shouldn't even have any leaves, and they should almost all have turned. The trees did start turning yesterday and today, but they are skipping the yellows and reds and instead going straight to green-brown. -
Bob Lacatena at 15:30 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
17, skywatcher, The big problem with Americans is that the MSM has failed. They ignore climate change, for the most part, unless it's something juicy that will help their ratings. Basically, the U.S. media has gone two routes. Most of them are commercial enterprises focused on making a buck (or just plain staying afloat). As such, there is no responsible reporting or selection of material. Everything is sensationalism. Respectable journalism is dead. The flip side is Faux News, which both is out to make a buck from their chosen shills (the fiercely and ignorantly right wing middle class and lower middle class) as well as to push a particular agenda, i.e. right wing "values." This means that they attack and misreport climate change religiously. The end result is that Americans are more concerned about other topics. There is concern about climate change, but not immediate concern. And I question Camburn's 50% number until he demonstrates some proof. I've seen the numbers on climate change dropping, but nothing like 50% thinking negatively about climate change (although I note that Camburn did not clarify what that 50% actually think). -
actually thoughtful at 15:27 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Camburn - sadly for humans on this planet - it doesn't matter what an opinion poll says: objective reality exists. And the scientific method is our best window on that objective reality. And of course that process tells us the world is warming, and that man is to blame. Now, while you are right to be concerned about the ocean ecosystem - it is going to collapse with or without the change in pH (yes there are other problems besides global warming - try over-fishing as just one). But oceans provide 5% of the global food supply. You should worry more about the flooding in the rice belt. Climate change will show no mercy - all our systems are adapted to the current climate, and the new regime will be much less forgiving, much less productive and much more volatile. Earth's carrying capacity for humans is probably well below 7 billion with currently deployed technology. I believe we are in an overshoot right now, with global warming being only one of the ways the interconnected systems of the earth are automatically acting to reduce the human population. Not happy about any of that, but I think it is important to focus on the core problem from time to time. -
skywatcher at 15:23 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
#12: "As far as an El Nino breaking temp records, it would have to be one heck of a El Nino." 2010 was hottest/tied hottest/damn close to hottest (depending on temperature record) with a moderate El Nino, during the deepest solar minimum in nearly a century. In the intervening years, solar forcing has at last risen on the way to a peak in the next few years and CO2 forcing continues to rise. It's going to take one heck of a small El Nino to break the temperature record. There, fixed it for you. Equatorial volcanic paroxysms aside, we'll be seeing new temperature records quite soon enough. As for the US versus the world, I can only shake my head in amazement that you are unable to look beyond your own borders. The effects of warming are being felt all over the US through some remarkable weather extremes, be they snowstorms driven by high precipitation, large floods or desperate droughts. Around the world, news events that are part of the growing story abound, Thailand, Italy and Central America being the latest extreme flooding victims. Clearly you'd like those to continue because in your opinion, it's cooling in the US? We can be sure that US daily record high temperatures will continue to far outstrip US daily record lows (cooling? sure...), and also equally sure that US Republicans will ignore the problem until it's pretty much too late to straightforwardly solve it. -
Bob Lacatena at 15:21 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
14, Camburn, I'm an American, too. Big whoop. Can you support your 50% statistic? -
Camburn at 15:18 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Mr. Mackie presented one of the best series on ocean ph I have ever read. I can only commend him on the highest order for this. -
Camburn at 15:13 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Sphaerica: This is the opinion of over 50% of my countrymen/women as it pertains to the USA. The last poll had jobs as number one, climate didn't even score in the top 20. I am expressing what the majority of Americans feel at this time. Concerning the current administration, the last poll had it at 32% approval of economic policy. -
scaddenp at 15:07 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
In short, utterly short-sighted, narrow-as-your-nose thinking from nation that you look for leadership from. I dont think you have a hope of predicting whether there will be El Nino or not in 2012 but I find it depressing that you have to hope for one to get any kind of action. When you can only get action during an upswing it makes you lament. "Oh its, warming" - no, change policy, its cooling, - no wait its warming again". This is mind-boggling unreasonable - send everyone back to school. -
Camburn at 15:06 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
As far as an El Nino breaking temp records, it would have to be one heck of a El Nino. As far as AGW, I have never been to concerned about that. I am concerned about the lowering PH of the oceans tho. We have had periods within the Holocene as warm as the projections from the models and survived quit well. In fact, one period was called the Holocene Optimum. But we have NOT had periods of warmth and the lowering of the PH of the oceans within the Holocene. The extra co2 benifits plant growth, but is very detrimental to the oceans. I do not think the carrying capacity of the planet can continue if the effects on sea life is as currently presented as the oceans are still a major source of food. -
Camburn at 14:51 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
scaddenp: I am sure there will be more El Nino's, but not in 2012 as the prediction is for a moderate to strong La Nina. There are so many things wrong with the current administration it is hard to start. Perry is at the bottom of the pack as far as Republicans. The flavor of the week is Cain, but he is getting out of flavor now. As far as climate, the US has been cooling so that is a hard sell. And the current economic climate because of the spending and increased debt of the Feds is so bad that people are concerned how they are going to eat tomorrow and not worried about next week.Response:[DB] "As far as climate, the US has been cooling so that is a hard sell."
Straw man. You say climate but mean weather/season. It is November in the USA so the temperatures do their seasonal trend downwards. Seasonal cycle superimposed on the long-term rise in global (not just the US) temperatures.
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scaddenp at 14:46 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
So Camburn, are you trying to say that you dont think there will be any more El Nino's and so we dont need to worry about global warming any more? It looks to me like only a moderate El Nino will enough to break all surface and satellite temperature records. If you dont like the current administration do you think an alternative are going to get real about climate? (isnt Perry leading runner?). -
Camburn at 14:18 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
As an American I am deeply unhappy with the current administration. As far as El Nino, it will be a La Nina instead. -
renewable guy at 13:32 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
I'm used to thinking about co2 only and when I see 48 gigatons it threw me off. I'm assuming 48 gigatons is all ghg's combined. -
actually thoughtful at 13:31 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
I am fervently (feverishly?) hoping for a big fat El Nino during the US election cycle in 2012. Nothing like a little heat to add a little heat to the discussion. Deeply unhappy with the irrationality of my fellow Americans. -
Bob Loblaw at 13:23 PM on 7 November 2011Watts, Surface Stations and BEST
Muon: an IR thermometer can only measure remote objects (e.g., the dead grass lawn) to the extent that the IR radiation received from the object is transmitted through the intervening atmosphere. No problem when the object is 1-2m away. More of a problem for distant objects, as you get more and more of the atmospheric IR in the path. It would depend on the exact range of wavelengths used, and such things at atmospheric humidity. A really long path? Yes, you'd get something largely dependent on air temperature. If you still have the IR thermometer, try pointing it at the sky some time. Compare clear skies to overcast, and high overcast to low overcast or fog. If you don't know what to expect, try guessing first. I'll hold off on clues. As for the "equilibrium temperature", I think you're missing something. The surface (the dividing plane between ground and air) has no mass, so it can't store heat. All solar radiation absorbed must go somewhere - either emitted as IR, transferred into the air as thermal energy, conducted into the ground as thermal energy, or used to evaporate water. The system is always balancing energy input and removal. If you have steady solar input, and steady all other fluxes, you can get a constant surface temperature - and it will still be much warmer than the air temperature. It's the same energy balance I described for the temperature sensor. If I get a chance in the next day or two, I'll try to dig out some old research data of mine that has actual measurements of fluxes, and temperature gradients. -
Bibliovermis at 13:01 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
I suspect that the denialist response to being marginalized will be to claim that nobody ever doubted that mankind was responsible for the warming. The contention was always over resolution methods, with geoengineering projects on top of Business As Usual (BAU) trotted out. The cartoon show Futurama showed that humanity "solved" global warming by dropping mountainous slabs of extraterrestrial ice into the oceans every year, starting in 2063. Youtube: Futurama - None Like It Hot It's policy as described by nursery rhymes. I know an old lady who swallowed a spider, That wriggled and jiggled and tickled inside her. She swallowed the spider to catch the fly, I don't know why she swallowed the fly, I guess she'll die. -
actually thoughtful at 12:55 PM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Dana1981 - great post! I think it would be even more powerful if the animation ended showing the real trend AND the denier version. The visual contrast, at the same time, would be stunning. (Of course it would be so fun it would need a way to play it again). I would love to be able to link to that when I am whopping the deniers on Politico. -
adelady at 12:49 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
"When will we be able to take really effective action?" 30+ years ago. What we're now faced with is selecting from the least worst processes and outcomes, rather than the good, the best, the economical, the gradual or the preferable. The best analogy I can think of at the moment is the River Murray. We knew we were in deep doo-doo the day in 1981 the mouth of the river closed 'despite' all the management of flows and levels. SA irrigators started modernising and restricting their take from the river while those further upstream increased their take and kept on with their lax (or lack of) technology. (It's a good idea to shield your face from the flying spittle when you talk to SA farmers recounting their horror stories of visiting eastern state orchards with their primitive open channels blithely evaporating tonnes of water.) 30 years later? Still arguing. Still proposing that upstream irrigators should be able to take more than scientists say is the absolute maximum they should be allowed if the river is to survive. And they'll still be arguing if they get their way. The next drought reducing the river to a filthy trickle will be described, again, as the fickleness of nature. A bit of a parallel, within a single country, to the North-South divide we see unfolding with climate impacts largely caused by northern hemisphere countries being felt first and worst by those nearer the equator. -
Glenn Tamblyn at 12:29 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Le Monde have run the Down Escalator graphic & the indicators of warming graphis. Cool! -
Lloyd Flack at 12:06 PM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
When will we be able to take really effective action? I fear not for about twenty years. I think after continued warming and some nasty effects denialists will have become a spent force. But even after the denialists are marginalized (We won't completly get rid of them.) there will be problems about what should be done. The danger then will be panic measures and measures made more to make a staement of concern. These can unnecessarily push up the cost of mittigation. We will need to make careful and realistic calculations of the cost and benefit of mittigation measures. The denialist concern that mittigation measures could provide a means for special interests to rip off the populace is reasonable. I think we just need to be on guard against them. I think self righteousness on the part of climate change activists can make them vulnerable to exploitation by such interests. -
dhogaza at 11:22 AM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
Link to LeMonde. It's a blog post, actually, and the skeptical science graphic (and link to skeptical science) is on page two ... nice! -
dhogaza at 11:16 AM on 7 November 2011Sober up: world running out of time to keep planet from over-heating
The excellent graphic here ended up in Le Monde's coverage (credited) of the Nature paper discussed above. -
Tom Curtis at 11:09 AM on 7 November 2011Eschenbach and McIntyre - Seeing the BEST part of the Satellite Temperature Record?
Returning to Camburn's original point @3, I would like to note that the trends for the TLS channel are: From 1978 to Dec 2009: -0.327 degrees per decade (from the graph above) From Jan 1999 to Dec 2009: -0.165 degrees per decade. I would like to note that: a) While the trend has approximately halved (reasons for which are off topic) it has certainly not "stopped" as claimed by Camburn; b) The period of the 1999-2009 trend is probably too short to be statistically significant; and c) The trend is still of the same approximate magnitude as tropospheric trends, though opposite in sign. Therefore any supposition that decreases in stratospheric temperatures have ceased to cause the TMT channel to underestimate increases in tropospheric temperatures is entirely unwarranted. TLS data is available here, under the MSU_AMSU_v.2 folder, and the monthly folder: ftp://ftp.orbit.nesdis.noaa.gov/pub/smcd/emb/mscat/data/ -
Rob Painting at 11:08 AM on 7 November 2011SkS Weekly Digest #23
I find the 2nd panel of that cartoon particularly funny, and accurate! Cheers Muon. -
muoncounter at 10:59 AM on 7 November 2011SkS Weekly Digest #23
Speaking of cartoons, I hope everyone enjoys this from the Sunday New York Times:
-- full size source
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muoncounter at 10:52 AM on 7 November 2011Watts, Surface Stations and BEST
Bob, I suppose the IR reading is an approximation. I pointed the IR sensor at the furthest point from where I stood. The measured spot spreads out with distance; the temperature reading did not vary with what I pointed at. And I checked it with a local weather observation; they reported an air temp of 104F. Equilibrium temperature? A spot on the ground in the sun receives solar energy faster than the ground can conduct heat to adjacent spots in the shade. In such a case the ground temperature reading at one spot is much higher than its surroundings. That's not equilibrium. -
skywatcher at 09:42 AM on 7 November 2011Eschenbach and McIntyre - Seeing the BEST part of the Satellite Temperature Record?
Trying to ignore the off-topic parts of Camburn's points, I'll concentrate on this statement from #18: "We can observe that in the past 20 years the [stratospheric] temperature has been stable, within error bars." With the same data, the strong long-term decline in mind, and the closeness of the data to the fitted declining trends, this sentence can equally be restated as: "We can observe that in the past 20 years the [stratospheric] temperature has been declining, within error bars." Camburn is going up the down escalator here. -
Bob Loblaw at 08:05 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
I think I've realized what bothers me about the "skeptics" version of "the warming has stopped". I think it is a variation of the Fallacy of the Undistributed Middle. The question I ask is "what warming?" a) the warming due to human-induced increases in CO2? b) the warming due to a) plus all other factors that affect global temperatures? The temperature records shows b). Attribution studies attempt to tease out a) from b). Theory tells us that b) will not rise continuously at a steady rate: it will have fluctuations imposed on the long-term trend that is caused by a). Now here's the rub: the "skeptics" look at variations in b) and make statements like "the warming has stopped", but what they are trying to imply (whether they believe it or not, or whether they are just employing FUD), is that noting a change in b) means that a) has stopped. The word "warming" does not mean the same thing in a) and b) - that's the undistributed middle in the logical fallacy. To make an analogy, let's say we have a bathtub full of water. At one end, we have a small heater. At the other end, we measure temperature. Periodically, someone stirs up the tub. Over time, we see the temperature rise slowly, but it doesn't rise evenly because the mixing isn't uniform. Let's say someone periodically adds some ice at the thermometer end - that causes periodic drops in observed temperature. We know that the heater at the far end is still adding energy slowly warming the bath, but the "skeptics" want us to believe that the occasional drop in temperature (or decrease in the heating rate) at one end means that the heater at the other end has stopped - or even never existed at all. There is also (yet another) inconsistency in the skeptic position here: they often argue the strawman that climatologists ignore other factors when attributing the global temperature rise to CO2. Yet that is exactly what the "skeptics" are doing when they pretend that short-term fluctuations are evidence against the current scientific understanding of global temperature and the effects of CO2. -
Bob Loblaw at 06:23 AM on 7 November 2011Watts, Surface Stations and BEST
Muon: 138 F for surface temperature with an air temperature of 108 F is not at all a surprise to me. Yes, the gradients in that 2m height can be that large, and they can be sustained. Two questions: - what exactly do you mean by "equilibrium temperature"? - how did you measure air temperature with the IR thermometer? It's easy to envisage taking the temperature of the dead grass with one: point and shoot. But what exactly did you point the IR thermometer at to get air temperature? -
jatufin at 05:09 AM on 7 November 2011Watts, Surface Stations and BEST
I was a "weatherman" in army some 20 years ago. And these measurements were what we did. Our post was part of national network (civilian bureau), so we delivered SYNOPses every three hours. In my later life I've not been involved in climate science, but I'm proud those few measurements I (and my fellows) did long ago, are still part of the global dataset. We were trained not to make basic mistakes, and the issues about station locations were discussed. I feel always insulted when these accusations of "bias" or solid stupidity arise. I'm sorry for real professionals, who must take this kind of crap nowadays. -
cce at 04:44 AM on 7 November 2011Eschenbach and McIntyre - Seeing the BEST part of the Satellite Temperature Record?
GHG induced stratospheric cooling is most prevalent at about 50 km, roughly corresponding to the top line (TTS) on the STAR graph. Unfortunately, the SSU instruments failed in 2005 so there is no data since then. As others have said, the cooling was reduced after CFCs were phased out in the mid '90s. Also, the higher altitudes have larger solar components, so the solar cycle tends to interfere with any eyeball-based analysis. -
cynicus at 04:42 AM on 7 November 2011Eschenbach and McIntyre's BEST Shot at the Surface Temperature Record
Have RSS or UAH discussed the discrepancies between the satellite products and the other reconstructions? Perhaps through replies to the Fu, V&G and Zou papers? Are there proxy temperature reconstructions covering the last four decades? Would be nice, perhaps, to have these in the mix as well... -
dana1981 at 02:34 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Some interesting comments here. My main concern is the same as muon @53 - that Curry has repeatedly used the phrasing "warming has stopped," which implies a termination. "Paused'", while not a good descriptor, at least implies that it will soon resume. Pielke used the same phrasing. When dealing with global warming, about which a large group of people are trying to convince the public that global warming really has stopped, or at least is nothing to worry about, such inaccurate and cavalier language is unwise and damaging. DNFTD. -
muoncounter at 02:13 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Tom#57: "you need to go back 14 years and pick one of two out of 240 possible ten year trends." I think that is an excellent and very compelling point. If this (2 out of 240!) was the strength of the warming argument, the skeptics and pseudo-skeptics would be jumping up and down crying 'Foul!' for good reason. But this is the strength of the pseudo-skeptic argument, so it must be ok. -
Dikran Marsupial at 02:02 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Tom@57 Your method is way better than Curry's approach, a single time period which is so short that the test for the trend doesn't have useful statistical power and has a cherry picked startpoint tells you precisely nothing about the trends. It says quite a lot about Prof. Curry's grasp of statistics, as an experienced scientist she should be able to formulate her hypotheses uambiguously and rigorously test them before promulgating them. -
Tom Curtis at 01:54 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
muoncounter @53, I am in wholehearted agreement with everything you say. IMO Curry has behaved despicably throughout. Her new wording, which certainly lacks clarity, is not what she was originally maintaining. It is, however, important to know she is not saying the same thing, and to criticize he as though she where saying the same thing. Regardless, however, even for what she is now saying, she is not justified in cherry picking start dates. At a minimum she should have been doing what I just did in 55. Even that, Dikran now advises me, is not a proper test. But it would certainly be better than cherry picking a single year, and as can be seen the results do not encourage her pretense. This whole storm started because Curry insisted that a single cherry picked data set of less than 10 years using dodgy end data showed us something significant. Well, to find a 10 year interval in the BEST data with a negative 10 year trend, you need to go back 14 years and pick one of two out of 240 possible ten year trends. That's quite some cherry pick she indulged in. -
muoncounter at 01:50 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Here is another way to look at long vs. short:-- source The red is BEST with a 12 month mean; green is the linear trend. Then use the detrend operator to remove that, yielding the blue curve. Sure looks like the blue oscillates around 0; but if you wanted to play the 'eyecrometer pick-a-trend' game, are the peaks at the tail end of the blue curve trending up? Or does 'warming stop' every 4 years or so?
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Tom Curtis at 01:42 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Out of interest, and using the last 30years of BEST data, the results of my test are: 30 Year trend: 0.275 degrees C per decade Number of 10 year trends less than zero: 2 Number of 10 year trends greater than twice the thirty year trend: 17 Total percentage of 10 year trends < 0 or > twice the thirty year trend: 7.9% So if my test has any value, the long term trend does not completely dominate short term variations yet, but it's very close. Out of interest, the two negative ten year trends where June 1987 to May 1997, and Dec 1987 to Nov 1997. The most recent ten year trend at double the long term trend was from March 1993 February 2003. -
Dikran Marsupial at 01:38 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Tom, the problem with that approach is that the intervals are not independent (due to the overlap) which would invalidate the comparison (although picking a startpoint ater looking at the data, as Prof. Curry suggests, invalidates the test as well, especially if it coincides with a peak in ENSO!). How much of an effect that would have I couldn't say, but it seems a better approach to use GCM or synthetic data, where you know this isn't going to be an issue (although if you have the synthetic data you could test to see how much difference it makes). -
muoncounter at 01:36 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Tom C#49: Curry's phrasing is confusing at best and quite possibly an attempt to mislead."What is of interest on this timescale is whether natural variability (forced and unforced) can dominate the AGW signal on decadal timescales and produce a ‘pause’ or a ‘stop’."
With that, she plays a very delicate game of semantics. The words 'pause' and 'stop' confuse the question. Anyone who hears the superficial 'warming stopped' does not hear the following 'because of a relatively large short term variation' and takes away only the carefully crafted message. If she agrees that "identifying an AGW signal on this short timescale isn’t useful," then she must agree that saying 'warming stopped' due to a short-term variation is a misrepresentation. All she can claim is that the short term variation is indeed large enough to mask the ongoing rise and make it appear to cool for a few years - something we see clearly demonstrated in the animation in Figure 1 in this post. But to imply this short variation is a 'pause' or 'stop' in the long term trend is an overreach. It is akin to Pielke's 'the trend has changed' based on a few years. What of all the past 'pauses' or 'stops'? Did warming stop each time? Suppose that your route up a mountain includes a detour down a small valley where you camp for the night. The next morning you continue climbing. Curry and Pielke would describe the overnight as 'climbing has stopped'. That would give the casual observer the incorrect message that you might be on your way down. Such an ambiguous (and false) report could delay a rescue team from reaching your correct position. But perhaps that's the reason for these semantic debates; look how much effort has to be spent attempting to set it right. Bravo to tamino for calling her out in front of her own denizens. When she’s asked point-blank for the scientific basis of her claims she changes the subject. When she’s shown the error of her ways she refuses to admit it. Science by pronouncement: As tamino says "It’s not a crime. It’s a sin."
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Tom Curtis at 01:17 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Dikran @50 & 51, I don't have your statistical fire power, but I assumed you could answer Curry's purported question by determining the long term (30 year trend), and then generating all trends of a shorter length (say 10 years) over the interval of the thirty year trend. For 10 year trends, there will be 240 overlapping 10 year trends using monthly data over the 30 year interval. Clearly the average of all the shorter trends will approximate closely to the long term trend. With this data, Curries question reduces to, will at least 5% of 10 year trends have a trend at least twice the long term trend, or of opposite sign to the long term trend. If the answer is yes, then short term factors can still swamp the long term trend. If no, then they cannot. Now, probably in about 50 years, the answer will be unequivocally "no". At the moment, the answer is very close to "no", but perhaps not. Certainly, however, you will not answer this question by looking at a single cherry picked trend, and especially if you allow yourself the use of dodgy data (April and May of 2010 in the BEST data) to fudge the answer. Have I got that right, or have I sawed my way through the branch. -
Dikran Marsupial at 01:02 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Just to add, the statistcal power calculation I tried to discuss with Prof. Pielke Sr is exactly the way in which you would go about assessing the likelihood of the expected trend being swamped by noise. The recipe is basically as follows: (i) generate lots of synthetic time-series with the expected trend (say 0.2 deg per decade) and ARMA(1,1) noise similar to the observed data. (ii) for each sesies calculate the statistical signiicance of trends over various timescales (iii) for each time-scale, calculate the proportion of trends that reach statistical significance (iv) plot these proportions as a function of the length of trend and label the y axis "statistical power". Statistical power is the probability of rejecting the null hypothesis when it actually is false, so in this case it is the probability that the noise can dominate the AGW signal. So that the test is symmetrical, I would suggest that the power should be 95%, so you just need to use a window lengh long enough to have a statistical power of 95% or greater. I expect this is around the 17 year mark. I hope to have a go at this mysel at some point. -
Dikran Marsupial at 00:53 AM on 7 November 2011Global Surface Temperature: Going Down the Up Escalator, Part 1
Tom Curtis wrote: "I am going to go out on a limb here, and disagree with both Dikran Marsupial and [some other bloke hardly worth mentioning]." HERETIC!!!!! ;o) The problem is that Curry's second statement isn't meaning full for analysis of the observed trend "What is of interest on this timescale is whether natural variability (forced and unforced) can dominate the AGW signal on decadal timescales and produce a ‘pause’ or a ‘stop’." because how can you tell whether natural valiability is dominating the AGW signal or if the AGW signal isn't there anymore? You can't answer the question posed by looking at observations as you don't know which hypothesis is correct. You could however use synthetic data (as Tamino has) or the output of GCMs (as Easterling an Wehner did), where in both cases the AGW signal is there by contruction. In summary, you can't answer Curry's question by looking at the observed post-1998 trend, but the question has already been answered in other ways (includng by Santer et al, whom she cites!). The thing that worries me is that we now have a climate scientists on record as having said 1998 is a reasonable startpoint for assesseing a trend.
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