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Eric the Red at 22:42 PM on 21 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
Actually Tom, I find the opposite to be true. There are clusters of values depending on the method used; models tend to yield higher values, temperature data lower, etc., resulting in several peaks within the distribution. KR presented a nice listed of climate sensitivity studies in #188. Those that used primarily CO2 to determined climate sensitivity arrived at the highest values as the Sanderson paper had a range of 2.45 - 7.32 and Hergerl 1.5 - 6.2. Those that incorporated higher natural components arrived at much lower estimates; Schneider 1.08 - 2.3 and Harvey 1 - 2. In some of these studies the most likely value was less than 2, in other it was greater than 4. To accept a mean value at this point is unwarranted, as it has a high probability of being wrong by more than 0.5C. Risk management may be fine for politicians and insurance agents, but is fruitless in scientific work. I would advice politicians, or anyone else, to bet on any value for climate sensitivity, either high, low, or middle. -
Bern at 22:42 PM on 21 June 2011Australia’s contribution matters: why we can’t ignore our climate responsibilities
Dikran, that's a good image to use. I'll keep that in mind, next time I hear this argument. -
CBDunkerson at 21:57 PM on 21 June 2011Websites for Watching the Arctic Sea Ice Melt
Heh... was just on my way here to post that map les. Also an article on it here. The map you included above seems to show that the really thick sea ice (5 to 10 meters) which used to cover a large portion of the Arctic ocean is essentially gone (just a few scattered dots of 5 meter ice) and most of the remainder is 3 meters or less. This doesn't seem radically different from past estimates so I suspect the PIOMAS volume values have been in the right ballpark. The article above also has an interesting ice thickness graphic for Antarctica. Looks like they are going to start their data record from January 2011. They launched in April 2010, but presumably they don't want to use data from the calibration and early validation period so 1/1/11 is a good start point. They've been validating the satellite readings against plane and ground measurements and have completed that through February. Will likely continue validation for several more months before releasing satellite results without extensive cross-checking. -
Bob Lacatena at 21:42 PM on 21 June 2011Websites for Watching the Arctic Sea Ice Melt
As a side note, melt pools first appeared this year on North Pole Web Cam 1 on 6/19 about a week ahead of last year (6/25). -
les at 21:24 PM on 21 June 2011Websites for Watching the Arctic Sea Ice Melt
33,35,65... Cryosat-2 just around the corner!
I share your excitement - not least because I used to work with some of the team on envisat... evil bastards, working to become millionaris using this stuff to take over the world via the UN on the back of the scam known as AGWgreat scientists, thrilled for them. -
Norman at 20:58 PM on 21 June 2011Linking Extreme Weather and Global Warming
Tom Curtis @ 129 I did look at the third graph and went to the web site it came from. This chart does show an increase in frequency of catastropic events related to weather but I can't find supporting documentation to interpret the information. What do they mean by catostrophic, how do they define the events, what are they looking at. It looks like an insurance company put this out so is it dollar value related? If I have more information on what the graph means it could be a strong point in showing an increase in frequency of extreme events. -
Anne-Marie Blackburn at 20:55 PM on 21 June 2011Introducing the Skeptical Science team
Quality not quantity, Hoskibui ;) -
Rob Painting at 20:05 PM on 21 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
Arkadiusz - "conclusion that nature has "fared" surprisingly well during the PETM of ocean acidification and warming" Yes, but the current rate of ocean acidification is unprecedented in the last 65 million years. In fact, if the PETM carbon is from methane, acidification could be happening around 27 times faster today than during the PETM. Additionally, during the PETM ancient corals appeared to cop a bit of a hammering from bleaching events. Links for peer-reviewed papers, supporting these claims, are in the post. A global civilization did not exist during the PETM, but if it did, how do you think they would have fared given even that slow rate of change? -
Michele at 20:03 PM on 21 June 2011The Planetary Greenhouse Engine Revisited
@ Patrick Not at all, the mesosphere has to be convective as well as the troposphere. If the tropopause emits as BB the outgoing power should be σT^4= 138 W/m² and, assuming the CO2 is the sole emitting gas with a width of band of 1% of the total spectrum (we well know it is very higher), the real outgoing power should be 13.8 W/m² and this can be obtained with a δT/δz = 13.8/(2.5e-3) = 55284 K/m !!!!!!!! The same compute for the mesopause gives δT/δz = 6.8/(2.5e-3) = 2480 K/m !!!!!!!! Any other comment becomes worthless. The emitting CO2 is able to make up the convective upwelling motion and so the quasi adiabatic lapse rate with an outgoing power a little greater than (2.5e-3)10/1000 = 2.5e-5 W/m², i.e. always. The brightness temperature diagram ”(see here)” point up the fact that broadening of the CO2 band is quasi the same for the three planets having CO2 densities abysmally different. That means that the CO2 limits its action to set up the altitude from where the lapse rate starts, obtained by the balance of incoming and outgoing fluxes, and to do that are enough only a few ppm. Its effect is merely qualitative, not quantitative. -
skywatcher at 20:03 PM on 21 June 2011A visual deconstruction of a skeptic argument
What you miss is that 17GT of natural absorbtion of carbon only occurs because there is an excess of 29GT amount in the atmosphere. Without the excess human-produced carbon, absorbtion would approximately equal emission. Surely you're glad that the Earth is capable of absorbing at least half of our emissions, and thus reducing the rate our atmospheric impact by half... but sadly it's at the price of acidifying the oceans. -
Hoskibui at 19:57 PM on 21 June 2011Introducing the Skeptical Science team
I sneaked my way in with just one post (and few translations) - but yeah, great to see the faces behind the names :) -
Arkadiusz Semczyszak at 19:10 PM on 21 June 2011CO2 Currently Rising Faster Than The PETM Extinction Event
The conclusion is simple, works cited by R.P. give a very incomplete picture of the topic: what science says about PETM (despite citing the fundamental work). Among other things, Gavin Schmidt says that the changes were extremely rapid p.CO2. The second position (which I quote) is the conclusion that nature has "fared" surprisingly well during the PETM of ocean acidification and warming. -
JMurphy at 18:25 PM on 21 June 2011Linking Extreme Weather and Global Warming
Anyone wanting to look into record high and low temperatures could start at Maximiliano Herrera's site, although it might take further searching to actually find the dates for each country. However, national and continental records, with dates, can be found on one of his Wikipedia pages, showing that most of the records have been set in the last 50 years - and most of those since the 80s. -
Dikran Marsupial at 17:42 PM on 21 June 2011Australia’s contribution matters: why we can’t ignore our climate responsibilities
Whenever I hear the argument that our emissions in country X are too small compared those from country Y that there is no point doing anything about it, I always think of this demotivational poster
Which does a nice job of pointing out what a dumb argument it is. If none of us do anything, nothing will get done, and why should country Y (which usually has low per-capita emissions and lower standard of living) do anything to reduce emissions if country X (which usually has high per-capita emissions and standard of living) does nothing?
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les at 17:32 PM on 21 June 2011Who's your expert? The difference between peer review and rhetoric
28 - Chris: Regarding the changes in how publishing works etc. It's interesting to note that in HEP, ePublising started way ahead of many other disciples, for various reasons, not least of all access to cutting edge computing in the 80's. The result of that was - apart from the invention of the web - a vast increase in community based peer review. Almost ever paper published in HEP was/is issued as pre-print and widely circulated within and between labs and departments. I think folks a kind of missing a big part of the point of a/ publishing and b/peer review. An acceptable paper isn't, in any way, shape or form required to be definitively true. They are expected to advance knowledge through the introduction of new data or application of methods. Peer review is, principally, that prior art has been considered reasonably completely so that there is originality and that results which conflict with prior published work are considered satisfactorily. So, 'peers' are people who are well versed in the relevant field and would know the state of the art - or at least be able to competently check the facts as required. It's not hard. In the climate world I see two problems. First it is widely multidisciplinary. That makes it hard for someone up to their elbows in ice to know the full state of the art with sun-gazers. That's not new in academia and seems pretty well under-control. However, it is from this fact we get a lot of "it's the sun", "it's natural cycles" etc. pronouncements. The other issues is the wide range of material being hoofed around as 'new' which neither contains new methods nor new data; and which has neither originated from within a world of seminars, coffee hour chats, conferences, pre-prints and publications; let alone been subject to (narrowly speaking) peer-review. i.e. rubbish. -
Tom Curtis at 17:32 PM on 21 June 2011Linking Extreme Weather and Global Warming
Norman @120, the 2010 Chinese floods were not record breaking, but neither where they run of the mill. The displaced over 15 million people, and a 240 million people where affected by them. The problem here seems to be that you do not appreciate how global warming must impact in a chaotic system. Put simply the fact that the mean global surface temperature is 0.6 degrees warmer than it was a century ago impacts on every weather system. As the regional expression of that temperature increase is part of the initial conditions for every weather system on Earth, every weather system is a consequence of global warming. Note that this is a trivially true fact - it follows from the definition of "chaotic"; and it is also uninteresting. But not remembering it means you will hopelessly miss frame any search for the effects of global warming on extreme weather events. What is interesting is that for every weather system we currently experience, many, similar weather systems would be experienced on some other day, or some other year, or at some other hour; or possibly at the same day or hour but coming from a slightly different direction if the Earth was 0.6 degrees cooler. But they may not have occurred at the same frequency. Now it is true that for some weather systems we can look at them and see a direct reason why global warming makes them more frequent. For others, however, we can only say why global warming would make them more frequent with no hope of making any particular connection for any particular storm or flood or drought. Technically this is true even for the extraordinary events such as the Russian Heatwave, or the Brisbane floods. But it is true of all the other events as well. Therefore it is only by looking at changes of frequency that we can truly detect the signal of global warming. Because the extra 0.6 degrees is a factor in the genesis of every weather system, and because equivalent events in most cases would have happened in a cooler Earth, you don't show global warming was not a factor by saying that some other equivalent storm happened in the past. You can only show that global warming does not increase the frequency of extreme events by showing there has been no increase in the frequency of those events. Which brings us again to the third graph in my 116. Ignore the red events, which are geophysical and not impacted significantly by any plausible mechanism of global warming. (There is a slight connection between soil humidity and risk of earth quake, so I can't say no connection.) But all of the other events are events that can be impacted by global warming. Now if you ask which of them was caused by global warming, the answer is all of them. There is no other logically coherent answer. So ask instead the relevant and informative question, does the frequency of the extreme events increase with increasing temperature? The answer is plainly, yes! Not only does it increase with the overall trend in global temperatures over the period, but there is even a partial correlation with the temperature variations of individual years. -
Tom Curtis at 16:56 PM on 21 June 2011Linking Extreme Weather and Global Warming
Norman @118, the claim that humans contributed (other than by global warming) is a standard denier response to any flood. Immediately after the Brisbane floods of 2011 a skeptic of my acquaintance made that claim as a knee jerk response regarding Brisbane. In fact what humans had done to make the Brisbane floods worse was, they had built two major flood mitigation dams in the headwaters of the Brisbane river, the large of them designed to be able to safely abate 1 in 500 year floods; they had dredged the river to allow a freer flow of water; they had removed several small rocky islands, and broadened the channel at key locations for the same purpose; and they had removed the bar at the mouth of the river which in the past had acted as a natural dam to flood waters, greatly increasing flood heights in the city. But, not knowing anything about that, and not, in fact, knowing anything about the geography of Brisbane this skeptics reflex response was to immediately blame human activity. In Pakistan the situation is not so clear cut. First, in Pakistan there has been a number of major river works, including the installation of barrages to mitigate floods. On the other hand, the river had been allowed to silt up a little, and some forest hills had been heavily cleared for timber. So, human activity may or may have not been a net help, and certainly could have done more to mitigate the flood. What is certain is that these factors pale compared to the nature of the precipitation that caused the flood. When you have record breaking rainfall - in one city smashing the previous daily record by nearly 50% - the story of the flood is not how much silt was in the river. When the rain falls near the arid western frontier rather than in the typical wooded eastern mountains, the story of the flood is not deforestation. In this case the reason for the flood is very well known. It is a combination of the the blocking pattern that caused the simultaneous Russian heat wave, and record breaking sea surface temperatures in the Northern Indian Ocean. What humans did, or did not do may have influenced the depth of the flood by an inch or so - but the flood was caused by whatever caused that blocking pattern, and whatever caused the record breaking sea surface temperatures. Record breaking Sea Surface Temperatures. Global Warming. Hmmm! What possible connection could there be? -
Mike Palin at 16:33 PM on 21 June 2011Who's your expert? The difference between peer review and rhetoric
With all due credit to Churchill: peer-review is the worst form of scientific gatekeeping except all the others that have been tried.Moderator Response: [Dikran Marsupial] c.f. Newtongate ;o) -
Rob Painting at 16:24 PM on 21 June 2011What is Global Warming and the Greenhouse Effect?
Signmaster - simple answer is that CO2 is well-mixed in the atmosphere, because parcels of air rise as they are heated. Temperature gradients between warm and cool places creates wind which helps to mix CO2 in the atmosphere. Scientific explanation would cause your eyes to glaze over. As for volcanic eruptions these are localized events, and the rate of CO2 emissions can be very intense. You will note that when out-gassing finishes CO2 levels can drop rapidly as CO2 is carried away by winds/mixing. Fossil fuel combustion, by comparison, is a global phenomenon. Here's a pic of CO2 satellite measurements well above ground level:
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James Wight at 16:05 PM on 21 June 2011Australia’s contribution matters: why we can’t ignore our climate responsibilities
Australia can still be a leader. The Zero Carbon Australia 2020 Stationary Energy Plan made a convincing case that Australia can transition to a 100% renewable energy economy within ten years, by rapidly scaling up concentrating solar power technology. A follow-up report covering Australia’s transport sector is due out this year. It is an ambitious vision to transform the nation. It would stimulate the economy and get more people into the workforce. And if we lead the world in developing solar thermal technology, we will be in a position to sell it to the world, instead of scrambling to buy it from Spain at the last minute. If any country should take a leadership position, surely it is Australia. Australia is a rich nation relatively unaffected by the Great Recession. We do not have China’s problem of a rapidly exploding economy. We have an abundance of sunlight to harness. We have very high per capita emissions so we need to start earlier. We are the world’s 16th highest domestic CO2 emitter, largest exporter of coal, and soon-to-be second largest exporter of LNG. We have the world’s fourth largest proven coal reserves, 9% of the global total. Paleoclimate evidence shows that in the long term, slow positive feedbacks greatly amplify climate sensitivity, meaning the world must aim to reduce CO2 to 350 ppm to be sure of preventing dangerous anthropogenic interference. Using the cumulative emissions budget approach (which the Garnaut Review had no good reason for rejecting), even for a short-term 2°C target our global budget runs out in 20 years. That means the entire world, rich and poor, needs to be carbon-neutral by 2050 (or earlier). The richest, highest per-capita emitters like Australia need to transition the fastest to give the poorest countries more time. Australia’s per-capita share of the global budget, if you start counting now, runs out in just a few years. So Australia’s true proportionate contribution is to get to zero emissions in a decade. -
Stevo at 15:25 PM on 21 June 2011Linking Extreme Weather and Global Warming
Tom curtis @122 My apologies. I didn't read the graph correctly. That graph is exactly what I was asking for. Thankyou. -
actually thoughtful at 14:53 PM on 21 June 2011Linking Extreme Weather and Global Warming
Tom Curtis - (116) another great comment! Thank you for your contributions - I am really enjoying them. -
Tom Curtis at 14:30 PM on 21 June 2011Linking Extreme Weather and Global Warming
Norman @119:
First, the Moscow July average for 2010 was about 8 degrees C above average, not 5. It was literally off the scale for NOAA's chart. In contrast, the Siberian cold region was only 4 degrees below average (the circles do not touch, so the largest circles in that region are only the second largest on the scale).
Second, for the Moscow heatwave, 17 cells are shown with a value of 5 degrees plus; while for Siberia only two cells show a - 4 degree anomaly. Around the fringes of the Moscow heatwave are another 12 cells with a plus 4 degree anomaly, so even the fringes of that event constitute a far more significant heatwave than the Siberian cooling.
Third, as is fairly obvious, the Siberian cold snap is in fact part of the same weather pattern which caused the Moscow heat wave. Because of the anti-cyclonic pattern of NH weather systems, if one part is bringing hot air up from the south, than at a different latitude, the same weather system will be bringing colder air down from the north. Consequently whether a weather system is considered as bringing heat or cold overall should depend on the overall intensity of the system. In this case there is no question.
Finally, if just picking the Moscow heatwave and saying ergo global warming is cherry picking, which it is; then just picking the Siberian cold snap and saying ergo not global warming is also cherry picking. In 2010 there were four or five record breaking heat waves, most covering multiple nations. There were was one record breaking cold snap covering just one nation, and another very intense cold snap in part of Antarctica (and an intense heatwave in another part, though not as strong).
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dhogaza at 14:24 PM on 21 June 2011When scientists take to the streets it’s time to listen up
'Eric the Red wrote: "I have seen that happen repeatedly here."' Waiting, waiting ... particularly for an example that isn't an own goal for denialists, because we are subject to the occasional flooding of posts pointing to papers that contradict the contrarian points a poster attempts to make... Oh, wait! Maybe that's what you're trying to say! You've seen *denialists* repeatedly fail here ... -
scaddenp at 14:09 PM on 21 June 2011Linking Extreme Weather and Global Warming
"Many of the events in the graph in #116 are not cause by global warming, so a correlation is difficult." Well we can rule out the "geophysical events". However, what makes you so sure other events are not caused by global warming? Because you can assign another proximate cause without considering ultimate causes? -
scaddenp at 14:04 PM on 21 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
Public policy in the face of incomplete data/understanding is a bet which needs to incorporate most likely and also the precautionary principle. At the moment, policy (do nothing) appears to be gambling on sensitivity less than 2 (less than 1 even), which fails in both regards. Me, I would bet on the sensitivity of the models which most accurately track temperature trend on 30 year cycle over period where we have reasonable accurate temperature and forcing data. -
signmaster at 13:59 PM on 21 June 2011What is Global Warming and the Greenhouse Effect?
I just have a question, as CO2 is heaver than air how does it get up into the higher atmosphere? When there is a volcanic eruption there is often warnings for people to keep out of the lower areas due to build up of CO2. -
Eric the Red at 13:56 PM on 21 June 2011Linking Extreme Weather and Global Warming
Norman, The Pakistani floods are nothing out of the ordinary, as they occur roughly every decade. The Russian heat wave was certainly an anomaly, shattering the previous record which stood for over 70 years. Both of these events appeared to have been caused by the same blocking pattern. Many of the events in the graph in #116 are not cause by global warming, so a correlation is difficult. Many of the nations reporting record high temperatures in 2010 do not have consistent temperature records of more than 50 years, so that a comparison with earlier periods of the 20th century is impossible. -
Tom Curtis at 13:55 PM on 21 June 2011Linking Extreme Weather and Global Warming
Stevo @117, the graph in my 116 shows an increase of between 50 and 100% in the number of extreme weather events from 1980 to 2008. That certainly seems statistically significant and over enough time to me. -
Eric the Red at 13:45 PM on 21 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
I see no reason to expect the climate uncertainty to be skewed towards the high end. One should read some of the papers presented by KR at 188, which includes the Annan and Hargreaves work. The papers which base their calculation of climate sensitivity on temperature data indicate a lower value. The Padilla paper list 2.0 as the most likely value. Modeling methods consistently yield higher values. There is some question as to the validity of incorporating the paleoclimate data as conditions differed greatly from the present. I see no evidence for a tightly centered range close to three. On the contrary, the range is rather broad, with each line of evidence generating sub peaks and curves within the larger range. Risks assessment may be useful for political and insurance purposes, but should not be incorporated in this scientific analysis. I would not advise anyone to ignore scientific practices and accept a questionable value for anything. I do not know why you would. Based on the previous analyses, there is less than a 50% chance that the climate sensitivity falls between 2.5 and 3.5. Why would politicians bet on high or low climate sensitivity in the first place? -
scaddenp at 13:31 PM on 21 June 2011It's methane
Crispy, my understanding is that the accounting for methane is based on effect that methane has before it is oxidised to CO2 compared fate of plant carbon if it hadnt been eaten by ruminant. You might like to look up the GWP (global warming potential) for more detail. -
csala at 13:27 PM on 21 June 2011A visual deconstruction of a skeptic argument
You say saturation I say equilibrium The people that wrote and commented on this post are much smarter than me but I have a different read on the information presented and humbly share. 800 g-tons of CO2 goes up of which 29 are man made 788 g-tons are assimilated back in carbon compounds The argument for global warming then is that because of saturation in the bio-system an excess of 12 g-tons is left aloft as a greenhouse gas blanket that will do its dirty deed as this excess iterates. My take on the presented argument is this. If I am to believe that there was equilibrium in the eons of time before industry, then how is it, that in this spec of geological time the earth suddenly, coincidentally went out of equilibrium. Well......, according to this presentation: 771 g-tons are naturally produced by the earth BUT the earth is in chaos because it is feeding on itself and collapsing the atmosphere 788 g-tons are assimilated back in carbon compounds A net deficit of 17 g-tons will regularly occur should all human activity cease immediately. Oh,... You say that equilibrium would be restored by natural processes should all human activity cease immediately. The earth would just immediately quit gobbling 17 g-tons more than it makes but can't gobble 12 g-tons more without relatively immediate and cataclysmic consequences to the planet. I think the math is being made to suit the argument. I argue homeostasis. No doubt the impact of human activity is felt across the spectrum of macro bio processes but I must add. "Exploiting the Earth—using the raw materials of nature for one’s life-serving purposes—is a basic requirement of human life. Either man takes the Earth’s raw materials—such as trees, petroleum, aluminum, and atoms—and transforms them into the requirements of his life, or he lives miserably. No fine arts, architecture, Science Channel, space programs, ecco-travel. Life as hunter/gatherers in many parts of the world where this is the norm, leave both the people and the land stripped and parched. To live, man must produce the goods on which his life depends; he must produce a means for homes, heat, transportation, technological multipliers such as computers, electricity, and the like; he must seize nature and use it to his advantage. There is no escaping this fact. Even the allegedly “noble” savage must pick or perish. Indeed, even if a person produces nothing, insofar as he remains alive he indirectly exploits the Earth by parasitically surviving at the expense of something else. The basic principle of environmentalism is that nature (i.e., “the environment”) has intrinsic value—value in and of itself, value apart from and irrespective of the requirements of human life—and that this value must be protected from its only adversary: man. Rivers must be left free to flow unimpeded by human dams, which divert natural flows, alter natural landscapes, and disrupt wildlife habitats. Glaciers must be left free to grow or shrink according to natural causes, but any human activity that might affect their size must be prohibited. Naturally generated carbon dioxide (such as that emitted by oceans and volcanoes) and naturally generated methane (such as that emitted by swamps and termites) may contribute to the greenhouse effect, but such gasses must not be produced by man. The globe may warm or cool naturally (e.g., via increases or decreases in sunspot activity), but man must not do anything to affect its temperature. [ -rant snipped-]Moderator Response: [Dikran Marsupial] If you want to understand the variations in atmospheric CO2, both recent history and on a geologiccal timescale, I can strongly recommend you read David Archer's primer on the carbon cycle, reviewed here. -
Norman at 13:24 PM on 21 June 2011Linking Extreme Weather and Global Warming
Tom Curtis @ 116 I have already seen the information on the 17 Nations that had record high temps in 2010. I guess there are currently around 195 countries on Earth (does change around a bit). What I was looking for is the entire data set of the World's Countries record high and low temps and in what year they took place. I could not find such information so my research is uncertain at this time as to determine if this is significant or not. Maybe in the larger data set clusters of record high and low are the norm and not the exception but only a complete data set will answer this. If you know how to find one I would be thankful. -
Norman at 13:19 PM on 21 June 2011Linking Extreme Weather and Global Warming
Tom Curtis @ 116 I don't think including China's flooding will help convince anyone that Global warming is increasing extreme weather events. Yangtze River has flooded 1000 times in 2000 years. The Yellow river has a long history of tragic floods. I would need some really solid evidence that floods in China are getting worse. China's floods are most frequent events. -
Jeff T at 13:16 PM on 21 June 2011Introducing the Skeptical Science team
It's great to see the faces and bio's behind the writing! -
Norman at 13:10 PM on 21 June 2011Linking Extreme Weather and Global Warming
Tom Curtis @ 116 I must state I do like the depth of thought and intelligence you display in your posts. You really do provoke thought. Thanks. Here is one on the Russian Heat Wave of 2010. Most are commenting about the unprecedented heat wave but what about the unusual cold at the same time in Siberia. Moscow was about 5 C above normal but at the same time Siberia was 5 C below. Did that set some record cold for this region? No one mentions it so I don't know. I can't find a resource for normal or record temps for Siberia on the web (such as Intellicast or Accuweather). Russia Heat wave of 2010. -
Bern at 13:10 PM on 21 June 2011Introducing the Skeptical Science team
I'll add my thanks to the team. Great work pulling the articles together. SkS is one of the first websites I refer people to if they want to actually learn about climate science (and sometimes even if they don't!) -
Norman at 13:02 PM on 21 June 2011Linking Extreme Weather and Global Warming
DB, On the Pakistan flooding issue. This article is a brief history of flooding in that area. 12 major floods in 69 years seems to indicate that this area is prone to floods and large floods are not a rare event. Can you link other weather related disasters in some of the flood years. It is hard for me to get much global weather destruction of earlier days. Pakistan flooding recent history. Another article does suggest the possibility of warming but also gives another reason as why this flood was so devestating. Man interference may have made the flood worse. -
Crispy at 12:51 PM on 21 June 2011It's methane
I wonder if someone could clarify a point for me? When sceptics say "you'll have to stop breathing then, because you're exhaling CO2" I point out that animal respiration is just part of the natural carbon cycle, (circulating 400Gt of CO2 a year), and that any carbon we breathe out was first captured from the atmosphere through photosynthesis to enter the food chain. Cow burps are treated differently however, and are seen as part of the problem. Is that because the carbon from the plants going through the cow is being converted (in part) to the more greenhouse active CH4, rather than merely being returned as CO2? (I realise cattle have a broader greenhouse footprint because of transportation and energy used in grain cultivation and so on, but I'm just curious about the methane here.) Many Thanks. -
Stevo at 12:49 PM on 21 June 2011Linking Extreme Weather and Global Warming
Is there a definition of what counts as an extreme weather event? If so, is anyone plotting them over time to determine their frequency? I'd be keen to find more information on this topic. Tom curtis' @ 116 provides a good example of frequent exteme recent weather events but is there a reliable record of these over a statistically significant period of time? -
Bern at 12:48 PM on 21 June 2011When scientists take to the streets it’s time to listen up
Stevo, I think you hit the nail on the head with your last sentence. It's a common political tactic. Scream your side of the argument to the heavens, and then shut down your opponent so they can't present their side. Alan Jones did just that to David Karoly in that recent radio inquisition. I've seen other 'sceptics' use exactly the same tactic on mainstream TV (much to the shame of the so-called moderators of the discussions). It seems the scientists have just about run out of patience, and might even think about being a little bit rude to get their point across (certain rap videos notwithstanding! :-) -
Tom Curtis at 12:12 PM on 21 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
Eric the Red, given the range of independent studies based on independent data that indicate a range of values centred close to 3, it is very foolish to assume the marginal values are at all likely. There are several reason for this. First, as a matter of pure science, if you combine the evidential weight of multiple independent lines of evidence, you get a much more tightly constrained value than any of the independent lines. This can be seen by comparing the ranges of the three independent lines of evidence discussed by Annan and Hargreaves (mentioned by Albatross @192). They, of course, just discussed three lines of evidence. Given that nearly all the lines of evidence generate ranges centred close to three, if a similar technique where applied to all the evidence, a range very tightly centred on three would be the result. It is certain that the range of such a study would be within the range determined by Annan and Hargreaves, and is likely to be narrower. (My guesstimate would be a 95% confidence range around 2.5 to 4) Second, as a matter of policy, given a range of uncertainty, you should base your decision on a probability weighted estimate of loss or gain for each outcome. As the expected adverse impacts of global warming rise with increasing climate sensitivity, to that extent the climate sensitivity you should assume for policy purposes should be weighted towards the upper limit rather than the lower limit. Personally I don't expect that to happen, or argue for it. I want politicians to just accept the IPCC mean value (3) and base their policies on that. I expect that because, given available evidence, it is the more likely to fall close to the actual value than any other choice. As such, I am advising people to ignore standard decision theory or mini-max strategies both of which (as noted above) would require using a significantly higher value for policy settings. Now, can you give one good reason why it would be sensible for politicians to bet on a low climate sensitivity when the probability that the value is wrong is significant, and assuming a low climate sensitivity in their response to global warming will maximize the adverse consequences of global warming? -
Tom Curtis at 11:46 AM on 21 June 2011Linking Extreme Weather and Global Warming
Norman @115, because of the chaotic nature of weather, it is impossible to look at a single event and say this would not have happened, or not been as bad without global warming. So if you pick any single event, you are cherry picking. This is even true of the Russian Heatwave of 2010:
The Russian heatwave of 2010 is literally unprecedented in history. There is no historical record of a heatwave in Russia as intense of that of 2010 (though there is one that was a few days longer). Immediately after the heatwave, there was a denier jumping onto every site he could and posting a list of literary references to Russian heat waves, that he claimed where comparable or worse. His game was given away by one of the quotes which actually quoted temperatures, around 5 degrees lower than the heat wave of 2010, and there is no reason to believe any of the others quoted where any worse. On the contrary, there is every reason to believe the Russian meteorological deparment (whose name I can't remember) who said that no equivalent heat wave was on record in the last one thousand years.
That quote was the source of the often repeated claim that the Russian Heatwave was a one in one thousand year event. In fact, assuming a normal distribution (not a safe assumption) and relative to recorded July temperatures it was less than a 1 in 66,000 year event
Not content with that, that well known "alarmist" Tamino calculated that using the known temperature distributions for Moscow, including those known to have been affected by global warming, the probability of the event was just 1 in 260 per annum. Without the recent warming trend due to global warming, it would have been around 1 in 1,000 per annum. (As an aside, it is predicted to become an annual event by the end of this century with global warming.)
But I can't just pick the Russian Heatwave and say global warming. That would be cherry picking. Nor can I pick the Pakistani flood and say global warming. From memory the Pakistani Flood of 2010 was the second largest in extent, the largest in damage done, but relatively low in terms of lives lost (due to modern communications, transport and medicine) in the just over one hundred year record of Pakistani floods. Nor the much worse, but under reported 2010 China floods, nor the 2010 Indochina floods.
Nor can I point to any one of the seventeen (plus?) national heatwaves in 2010.
In Australia, I can't point to the three 1 in 1,000 year rainfall events that happened in three days in a 60 by 60 mile area, thus causing the Brisbane floods. Nor can I point to the record flood affected extent in Queensland that more than doubled the previous record. Nor can I point to that previous record, set in March 2010. Nor can I point to the 2011 Victorian floods which where the worst floods in Western Victoria "...far as [the Bureau of Meteorology's] records go in terms of the depth of water and the number of places affected". Nor indeed to the floods in the same area in September 2010.
If I point to any one of these events, and the list is no where near exhaustive, I am cherry picking. But what I can do is point to the combination of them all. And then it becomes clear that both the number and intensity of extreme events is on the rise. And nor is it just a function of ENSO. La Nina conditions certainly contributed to the extensive flooding in Australia this year, but in March 2010 when Queenslands previous record for flood extent was set, there was a strong El Nino.
Statistically, something unusual is happening with the weather. And in most cases there is an intuitive causal connection to global warming. Weather is complex, and chaotic, so the exact nature of the causal connection is in many cases still being thrashed out. But it would be shere folly to use that as an excuse to believe the statistical correlation between extreme weather events and increasing temperatures is a fluke.
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Albatross at 11:36 AM on 21 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
Eric @198, No. I'm flattered, byut my simple analysis of BPL's data is really not something you should be using to bet. Also, look at Knutti and Hegerl, the PDF is not symmetrical, it is skewed towards the high end. And AGW is not a betting game. -
Patrick 027 at 11:36 AM on 21 June 2011The Planetary Greenhouse Engine Revisited
Re Michele - the mesosphere on Earth is not convective. It is less stable than it would be with a zero or negative lapse rate, but there isn't much convection there. Generally, the convection that does occur in the Earth's stratosphere and mesosphere is thermally-indirect motions (heat pumps) forced by kinetic energy produced by thermally-direct motions (heat engines) in the troposphere; the kinetic energy - actually the fluid mechanical energy which is a combination of kinetic energy and APE (although the ultimate conversion of remaining kinetic energy to APE is the heat pump part) in the form of fluid-mechanical waves, propogates upward as gravity waves, equatorial waves of various types (associated with the QBO; I haven't read of this being thermally indirect or driving meridional overturning but I would think it has to be thermally indirect), and Rossby/PV waves (associated especially with the Brewer-Dobson circulation within the stratosphere and 'sudden stratospheric warmings'). The energy is absorbed above when and where kinetic energy is dissipated mechanically (mechanical damping of the waves) and otherwise converted to APE in thermally indirection motion with the resulting APE being dissipated radiatively (thermal damping of the waves). Really, we can think the CO2 molecules behave as heat engines which, colliding with the surrounding molecules, absorb thermal energy from them, and transform it to EM energy....Both the gradients are negative because the continuous growth of the geo-gravitational energy that phagocytizes them. So, the rising CO2 molecules never are in LTE, the thermal energy (needed to excite them until the resonance) is used for other different purposes (the rising of the entire air particle), and there can’t occur any radiative emission. ... The surface temperature is determined by the lapse rate and above all be the altitude where the rising air particles are stopped by the inverted slope due to the external radiative heating of a layer of the atmosphere above it. No, very much wrong and confused, sorry. The tropopause level doesn't necessarily or generally correspond to the effective emitting level. The fact that you can see spectra where some freqencies have brightness temperatures higher than the tropopause temperature should alone be a clue. Note also that the CO2 band is not only that part with the lowest brightness temperature; it extends outward from there. Same for water vapor, too. See 374 http://www.realclimate.org/index.php/archives/2011/06/unforced-variations-june-2011/comment-page-8/#comment-208838 383 http://www.realclimate.org/index.php/archives/2011/06/unforced-variations-june-2011/comment-page-8/#comment-208856 and some clarifying comments in between. Of course, also the surface radiation around 15μm forces and excites the CO2 molecules which could scatter it. I think this isn’t the case, otherwise, the brightness temperature around 15μm should be higher. The CO2 fully wastes the EM energy to heat close the ground and this can be partially converted back and emitted to space only at the top of the first convective layer above the ground. Actually near the center of the CO2 band, it is so opaque that much/most of the radiation emitted at the tropopause level is absorbed, relatively nearby. The net LW flux at the tropopause is or is close to zero; the effect is or nearly is saturated. Adding CO2 doesn't have much effect on the tropopause radiative forcing at the center of the band. It DOES have an effect a bit outside the center of the band, where it's opacity is intermediate (it will also have some indirect effect as stratospheric adjustment will affect the downward flux from stratospheric water vapor and ozone as well as CO2). The opacity for a given level of CO2 drops roughly exponentially away from the band center, which is why each doubling of CO2 effectively widens the band by a given amount and has a corresponding amount of radiative forcing (if there were only a tiny amount of CO2 then the band center wouldn't be saturated and the forcing would tend to be more linearly proportional to CO2 amount; for the amount of CO2 on Venus, other bands become important and the proporitionality if forcing to amount of CO2 is different again. (Also, the climate itself affects the forcing per unit amount change - different wavelengths have different relative importances at different temperatures; the radiative fluxes change; there are variations in water vapor and cloud overlap on Earth (etc. for Venus, though I'm not sure how the feedbacks work there), and the vertical temperature profile is important. Also there are variations in line broadenning and line strength, ... etc.) -
Eric the Red at 11:30 AM on 21 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
I am not picking anything. These are the ranges chosen by the three other posters. Betting under 2 appears to have a similar likelihood as over 4. -
Stevo at 11:28 AM on 21 June 2011When scientists take to the streets it’s time to listen up
ClimateWatcher @3 "Taking to the streets is an emotional exercise." Actually it is a political exercise - an attempt to draw public attention to an issue. That issue is the campaign by vested interests and certain political blocs to obscure or misdirect the message that AGW is real. The current denialist line is that the science is not consistant or conclusive. Doubt is cast over every detail the business as usual advocates can find but no consistant alternative thesis is put forward. Scientists are frustrated that their work so far is not being fairly reported. They've done (and continue to do) their work with regard to the science. The new task is to get the message out to the public because media and political policy makers have laregely failed to do so. Your comment suggests that scientists are not entitled to the same political rights as other members of the community. -
Patrick 027 at 11:04 AM on 21 June 2011The Planetary Greenhouse Engine Revisited
Re 20 guinganbresil - I think that's an interesting issue and I tried to estimate some things myself at another post - I think it was in comments at an earlier post by Chris Colose on his own blog. Perhaps a scale analysis (this may be over or underdetermined and there may be some errors, but at least this gives a sense of what might be done): U ~ L/T, Area ~ L^2, heat flux ~ R*L^2, where R is *a* radiative forcing, heat flux between hemispheres ~ U*L*(Th-Tc)*H*cp*density, rate of kinetic energy production by horizontal motion ~ L*H*U*L*(ph-pc) = U*H*L^2*(ph-pc) where ph-pc is a representative pressure difference between the cold and hot side and proportional to Th-Tc (at surface the difference will have an opposite sign than at the top of the overturning layer of depth H - or H could be an e-folding scale), kinetic energy supply ~ R * L^2 * 1-Tc/Th, viscous kinetic energy sink ~ viscosity * L^2 * U/H - or is it U^2/H, or U/H^2, I'll have to get back to that... mixing kinetic energy sink (mixing heat downward) ~ ? (could be negative or zero on the hot side - or incorporate thermally direct localized overturning on the hot side into the mixing term, and it would be negative if the export of heat by horizontal winds is sufficient to maintain a greater than adiabatic lapse rate), Actually I need to go back and specify R farther; Rh could be the net radiant heating of the surface in the warm hemisphere; Rc could be the radiant cooling of the surface in the cold hemisphere; 1-Rc/Rh ~ (1-Tc/Th), except that whatever kinetic energy is produced is eventually converted to heat anyway, which in terms of necessary heat flux would be divided into an addition to Rc on the cold side (kc) and an effective addition to Rh on the warm side (kr) so that for the actual Rc and Rh, 1-(Rc-kc)/(Rh+kr) ~ (1-Tc/Th), and Rc-kr = Rh+kr ... no wait, that can't be right... Rate of conductive heat supply to surface on cold side ~ L^2 * (THc-Tsurfacec)/H * K , where THc is the temperature at height H above the now go play with it. Some of the above clearly needs more work, but some things are clear: Note that you could have overturning with cold air masses sliding under warm air masses without actually having an adiabatic lapse rate. In fact, that kind of overturning decreases the lapse rate. With cold air coming in over a warm surface you could get something more like a troposphere, and perhaps some stable layer of air in the 'winter/night' hemisphere/region would be considered part of the global tropopshere as it is on Earth (although the troposphere is still not as stably stratified as the stratosphere - except maybe (I'm not sure) in the inversion near the surface, which is not the whole troposphere). However, in the polar nights on Earth, the troposphere, heated by horizontal import of warm air from warmer places, can lose that heat to the surface by radiation and conduction/mixing and can lose that heat to space (and the stratosphere) by radiation as well. With no greenhouse effect (specifically of the emission/absorption kind), the troposphere cannot cool by emitting radiation, and so either it must be warmer or the surface must be cooler to get the same heat flux, which must be entirely to the surface. Kinetic energy from the large scale overturning may drive downward mixing of heat; otherwise you have to rely on conduction/diffusion. Possibly the lapse rate would be such that the stratosphere does reach the surface. The troposphere might perhaps be a bubble on the hot side, which may extend somewhat into the night/winter side. The depth of the overturning layer in the night/winter side must be small enough for conduction to make up for what mixing cannot accomplish, to balance the heat supply - itself limited by the depth of the layer and the wind. Thus the layer may tend to be shallow. The tropospheric thickness on the hot side would be determined in part by the supply of cold air from the cold side, which would be determined by the wind speed and the depth of the layer which can lose heat to the surface at the necessary rate. So the troposphere on the hot side may also be forced to be shallow. If there is any solar heating of the air itself, this also has to be mixed and/or diffused/conducted downward. -
Chemware at 10:52 AM on 21 June 2011When scientists take to the streets it’s time to listen up
@3, ClimateWatcher: "Cold rationality" - clearly you are not a scientist, and have never participated in a "vigorous" scientific debate ! I also dislike your attitude of "Scientists should be seen and not heard", and find it rather patronizing. Getting back to the article itself, and attacks on scientists in general, what we are witnessing now is comparable to the Catholic church's attacks on heliocentrism, and to the Nazi's campaign against "Jewish Science". Fortunately, it has not reached the intensity of those attacks, but with trillions of dollars and political power at stake, I fear for the safety of all working scientists, particularly those with a high media profile. -
scaddenp at 10:42 AM on 21 June 2011Infographic: 97 out of 100 climate experts think humans are causing global warming
But evidence we have is that cloud feedback is near neutral. There is uncertainty but below 2 is not the way to bet.
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