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Comments 82051 to 82100:

82051. Tom Curtis at 11:59 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       Badgersouth @51, a search on google scholar for the terms ENSO & ("global warming" v "climate change") 2009 or later produces the following articles of interest: Models: Latif and Keenlyside, "El Niño/Southern Oscillation response to global warming", PNAS 2008 Collins et al "The impact of global warming on the tropical Pacific Ocean and El Niño" Nature Geoscience 2011 Both indicate that models disagree about the effects of global warming on the ENSO. Historical: Gergis and Fowler "A history of ENSO events since A.D. 1525: implications for future climate change" Climatic Change 2008 Gergis and Fowler indicate a significant anthropogenic effect on El Nino intensities:

       "Although extreme ENSO events are seen throughout the 478-year ENSO reconstruction, approximately 43% of extreme and 28% of all protracted ENSO events (i.e. both El Niño and La Niña phase) occur in the 20th century. The post-1940 period alone accounts for 30% of extreme ENSO years observed since A.D. 1525. These results suggest that ENSO may operate differently under natural (pre-industrial) and anthropogenic background states."

       Doran et al "Analyzing ENSO Period Changes in a Proxy Record Spanning the Last Millennium" Geophysical Research Letters 2009 Doran et al indicate a change in the frequency of ENSO shifts:

       "The time series model analysis of the Palmyra corals shows ENSO period changes that are similar to the broad patterns observed in the wavelet analysis (Figure 2). ENSO periods are generally higher during the pre-1850 interval (μ = 6.4 years, σ = 1.9 years, N = 9), while periods post-1850 are lower (μ= 4.0 years, σ = 0.60 years, N = 4). This 2.4- year decrease in ENSO period from pre-1850 to post-1850 is statistically significant (p < 0.1). In particular, three of the four estimated ENSO periods in the post-1850 interval are at or below the lower limit of periods observed pre-1850. Additionally, there is a shift in ENSO period at 1700 that is more pronounced than the shift observed at 1850. This earlier shift may reflect changes in forcing, such as increased volcanic activity..."

       Li et al "Interdecadal modulation of El Niño amplitude during the past millennium" Nature Climate Change 2011 Li et al conclude that warmer conditions are correlated with enhanced ENSO variability, a finding in agreement with Doran et al. I am making no claim to expertise, so I can't say that these studies are representative, and for most of them I have read only the abstract so I can't comment on their validity. They are, however, consistent with the evidence as I have seen it summarized.
82052. guinganbresil at 11:59 AM on 19 June 2011
       The Planetary Greenhouse Engine Revisited
       The "Greenhouse Effect" is an imprecise term. The effect of an atmosphere on the planet's surface temperature is affected by multiple atmospheric constituents. Greenhouse gases are the most obvious and most discussed, but suspended particles including liquid droplets, ice crystals, aerosols and dust also contribute. In the case of Venus, the top of the clouds are obviously opaque in the spectral region shown in figure 1 above. The regions in which CO2 is transparent show an emission brightness temperature corresponding to the temperature of the cloud tops. The contributions of different greenhouse constitutents are not additive. The CO2 in Venus' atmosphere only contributes to the planetary emission spectrum above the cloud tops - all the CO2 below the clouds does not affect the outgoing planetary spectrum. If one were to keep all else constant and replace all of Venus' CO2 below the 1 atmosphere altitude with dirt, the new equilibrium surface temperature would be a little less than Earth's, and the emission spectrum would be essentially the same. (Yes, I am ignoring the effect of the blocking of the very long wave emissions seen from Venus through the clouds - that is not the point...) The point is that the high surface temperature on Venus is clearly a result of the thick dense atmosphere through the lapse rate, and the IR absorption of CO2 is not a significant factor.
82053. John Hartz at 10:56 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       What are the latest findings on how the ENSO is being impacted by climate change? What's the most recent SkS article on this issue?
82054. Tom Curtis at 09:35 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       jerryd @38, I do not follow your reasoning. First, you state that the d13C of Cabonate is from 0 to 2. It is not possible that carbonate on the floor of the Tethys was closer to 0 per mil and hence depleted in C13. It seems that given the range of d13C concentrations you give for Carbonate, you cannot run the argument that you run against Kent and Muttoni. Second, given that the floor of the Tethys was carbon rich because it was a shallow, life rich sea, does this not suggest that Tethys carbonate is likely to have been C13 depleted relative to other carbonates?
82055. chris at 09:34 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       Sphaerica at 23:51 PM on 18 June, 2011 "Is it possible that carbon existed in some form prior to the PETM which we no longer see in noticeable quantities today? That is, could there have been some sort of release mechanism which entirely escapes our imagination, exactly because it all "let loose" during the PETM?" There is a possible answer that was reported at the American Geophysical Union in December which fits your question. Quoting from a write-up in Science by Richard Kerr (see page 142) reporting on a couple of talks on the PETM:

       "In the next talk, paleoceanographer Robert DeConto of the University of Massachusetts, Amherst, and his colleagues claimed that a larger source of carbon dioxide in Eocene times would have been the permanently frozen ground of polar regions. No ice sheets covered polar ground in Eocene times, and the land area of Antarctica was far larger than it is today, DeConto said. That would have made for widespread permafrost, storing organic matter that—if thawed and decomposed—would yield large amounts of carbon dioxide. In their model, extremes of orbital variations caused permafrost to melt in summer and release its carbon dioxide. Enough would have come out fast enough to drive the observed warming, DeConto said."

       That would fit your scenario...except perhaps the bit about "entirely escap(ing) our imagination"! Another group (A. Ridgewell et al) also suggest a role for Milankovitch cycles (earth orbital varibility) in the PETM:

       "Ridgwell and his colleagues included orbital variations in a computer model of early Eocene climate, when the world was slowly warming under a strengthening greenhouse. When the orbital variations in the model combined to make an extreme contrast between summer and winter temperatures, the model's ocean circulation would slow and stagnate. That allowed the deep ocean to warm, warming the sea floor. And that's where natural methane hydrates reside—the “ice that burns.” Warm them and they decompose into water and methane. That methane can escape the sea floor, oxidize to carbon dioxide, and warm the world."

       The role of orbital cycles as a factor in the PETM is quite appealing since the timescales (few thousands of years) are appropriate.
82056. JMurphy at 09:31 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       adrian smits wrote : "All I said was it appears cooler temps seem to create more violent weather events than a supposedly warming climate!" Rather than relying on appearances, can you provide any backing for any hypotheses you may have, especially if you believe that the global climate isn't warming ?
82057. scaddenp at 08:50 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       Further thought - Kent and Muttoni are assuming carbon from carbonate, but could also be subducting a pile of carbon-rich sediment, pushing them rapidly through the oil/gas window.
82058. chris at 08:41 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       jerryd at 07:49 AM on 19 June, 2011 O.K. that's very interesting jerryd. I haven't looked at the d13C data associated with the entire Paleocene/Eocene period with consistently raised [CO2] (rising to a maximum at the EECO). Do you have a paper/link where the long term d13C data are compiled? I guess the implication is that at least a good chunk of the increased [CO2] during this period was biogenic. And a couple of questions arise. Why were [CO2] levels maintained so high (2500-3000 ppm apparently) during this period? Was weathering particularly inefficient for some reason? And does the low values for d13C apply to the full period (from around 65 MYA to 50 MYA) or does it drop particularly during the apparent rise of [CO2] during the period ~ 55-50 MYA? There's no question that the d13C data are a fantastic bonus with which to supplement proxy data for absolute [CO2]. I have to say the Kent and Muttoni hypothesis is rather appealing since it does seem to provide a coherent explanation for post-Cretaceous [CO2] data, but if it's not consistent with the d13C data then that's not too good for the theory. Sounds like a promising area for further thought!
82059. scaddenp at 08:37 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       jerry - what about multiple event scenario? Elevated carbon in atmosphere, then volcanism in sedimentary basin releasing a spike big enough to trigger hydrate release at poles. With low pole - to equator gradient, the feedbacks release hydrate world wide. On longer term, the elevated temperatures speeded up methane production from sedimentary reservoirs (which are huge by comparison to surface carbon reserves). (This latter is what colleague is pursuing).
82060. Tom Curtis at 08:36 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       Norman @42, I'm glad you posted that quote as it tells my your source is rubbish. This is not because it assumes that because a certain type of event has had a natural cause in the past, that therefore it cannot have an anthropogenic cause in the the present or future. That fallacy is equivalent to a doctor assuming that because a cough can be caused by the common cold, that therefore your cough could not be caused by tuberculosis and ignoring all other symptoms. Rather it is because your source does not know that the Southern Oscillation and the El Nino effect are just two sides of the same coin, ie, the atmospheric pressure effect and the thermal effect of the El Nino Southern Oscillation. A source that cannot get that right is sure to miss such subtleties as that historical and some model evidence suggest that increased global temperatures are associated with an increased frequency of El Nino conditions. They are also likely to miss, as you have, that El Nino's are associated with East coast, not SW coast droughts in Australia, and the the drought in SWWA has persisted in through this very strong La Nina year. In fact the persistent reduction in rainfall in SWWA is most probably a result of a southerly shift in the prevailing westerlies due to the Hadley cell getting larger - almost certainly a consequence of, and historically associated with rising global temperatures.
82061. Bob Lacatena at 08:12 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       [Previous comment was a response to 46, Eric the Red]
82062. Bob Lacatena at 08:12 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       From Bednorz, the first paper you linked (emphasis mine):

       Precipitation is also an important factor in the ‘non-active’ regions. Only at the beginning and at the end of winter is air temperature the dominant parameter of snow-cover formation in northwestern Europe. In the middle of winter, when the temperature is well below zero, the increases in snow-cover depth are mainly controlled by precipitation (Clark et al., 1999).

       It's also important to note that that is a study of past climate, in a relatively steady, stable regime (1960-1993), in a very localized area (E. Europe). There is little that can be better than simplistically inferred from it about the impacts of serious climate change on global snowfall (or snowfall in other regions of the globe). The same applies to your second paper, which studies the period from 1901-1994, and only in Switzerland. While temperatures did rise in that period (at most, 0.5˚C), I believe the extension of what is viewed there to the globe, under a dramatically changing climate regime and greater temperature increases (and accordingly greater precipitation pattern changes) is unwarranted. In general, I believe your logic that overall snowfall will be diminished by the factor of the later onset of winter (cooler temperatures) and the early onset of spring (warmer temperatures) is valid, but the assumption that this factor will completely override any accompanying increases in precipitation during the winter months (due to other factors, such as specific humidity, and circulation patterns such as the Hadley Cell changes) is unwarranted.
82063. jerryd at 07:49 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       I just read the Kent and Muttoni paper (PNAS, 2008) ... It's interesting. However, I think the hypothesis is demonstrably wrong. Here's why: 1/ The long-term maximum in Earth surface temperature over the last 80 million years or so occurred at about 50-52 Ma. For better or worse, we call this the Early Eocene Climatic Optimum (EECO). 2/ I entirely agree with the paper that this peak in warming was associated with high amounts of carbon in the exogenic carbon cycle. There are several good arguments to support this notion. 3/ However, the d13C of carbonate is around 0 to +2 per mil (depending on age). (For those that I have lost here, see below). 4/ This means that, if the temperature rise was driven by CO2 from carbonate, there should be no significant change in the d13C of the exogenic carbon cycle. (The ocean having a d13C composition of nominally +1 per mil). 5/ In fact, the d13C of the exogenic carbon cycle reaches a prominent low at 50-51 Ma. This implies that the source of carbon was very depleted in 13C; that is, most likely related to organic carbon. Basically, there is no way to add massive amounts of carbon to the exogenic carbon cycle from carbonate and have a prominent long-term d13C excursion. **** After numerous scribblings on wet napkins, and trying to explain carbon isotopes and the carbon cycle, here's my best effort. Carbon has two stable isotopes, 12C and 13C. The ratio of these two isotopes is typically expressed in terms of d13C, with carbonate close to zero. Various reservoirs (ocean, biosphere, atmosphere) have different d13C. For whatever reason, it seems much easier for most people to think of things where carbon reservoirs are pools, and carbon isotopes are white (12C) and red (13C) paint. Consider the ocean as very light pink. Carbonate is white; organic carbon is red. The Kent and Muttoni paper suggests that massive amounts of white are added to a very light pink reservoir. It implies that the pool should become lighter. The geological record shows that, instead, the pool becomes a deep crimson.
82064. Eric the Red at 07:47 AM on 19 June 2011
       How would a Solar Grand Minimum affect global warming?
       yes, Since the last half of the 20th century was a time of high sunspot activity, a period of low activity would help set the bounds of the relationship (if any) between the sunspot cycle and global temperatures.
82065. Eric the Red at 07:22 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       There are several reference to the relationship between temperature and snowfall. Those areas which are belwo freezing for most of the year will likely see an increase in snowfall as temperatures approach freezing. Thesse areas are few. The rest will experience more days above freezing, and hence more rainfall amd less snowfall. http://onlinelibrary.wiley.com/doi/10.1002/joc.1014/pdf http://www.springerlink.com/content/k631170346751481/
82066. Eric (skeptic) at 07:02 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       A proxy for poleward migration of the subtropical jet (i.e. expansion of the Hadley cells) is lower stratospheric cooling at 30 degrees latitude, see http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00027.1 The TLS plot showing latitude cross section does show some slight cooling at 30 degrees:
       ignoring the two volcanoes. But that cooling seems to have leveled off.
82067. adrian smits at 06:54 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       When you're talking about the current temperature it should have a bigger impact on the weather than the 5 year average temps. All I said was it appears cooler temps seem to create more violent weather events than a supposedly warming climate!
82068. Norman at 06:36 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       Sphaerica @41 Here is an interesting article on Hadley cells. Info on Hadley Cells.
82069. Norman at 06:31 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       Tom Curtis @ 37 Here is some information you may find useful. History of Australia's droughts and causes. You may want to look at page 3 and below to see if global warming is causing an increase in severity of Australian droughts. Here is a quote from that page: "Many scientists believe that human activities associated with the generation of ‘greenhouse gases’ are causing climate change. (See STUDIES 2/2000.) This, however, does not cause drought as it has been experienced in Australia over thousands of years. Natural climate change in Australia is caused by two major elements – the changes in the pressure of air in the atmosphere circulating between Tahiti and Darwin (measured by the Southern Oscillation Index – SOI); and the temperature of currents moving across the equator from South America to the area to the north of Australia (known as the El Niño effect)."
82070. Bob Lacatena at 03:29 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       38, Eric the Red, I have found that one of the easiest ways to understand just one mechanism by which precipitation will change, and how that mechanism will be affected by climate change (and this change is already being observed), is to study the Hadley Cells. It's a fascinating subject, and easy to grasp. A quick Google will find you something at an introductory level, and you can go from there. The basic idea, however, is that the intense warming at the equator (or rather, at the point of direct 90˚ solar incidence, which is at the equator in spring/fall but moves up/down a bit with winter/summer) causes that air to rise, laden with moisture. This cycles up, then north/south, then reaches a point where it falls back down. The first point is that the area where it comes back down sees a lot of rain. The area in between is parched, and most of the world's deserts lie in these bands (but are, of course, subjected to other, local factors). Have a look at the globe and notice how most of the worlds deserts are just north and south of the equator, yet not at the equator, or just north of that arid band. Because the point of 90˚ incidence moves with the seasons, so do the Hadley Cells, bringing seasonally consistent/predictable rainfall or dry periods to certain regions. An increased global temperature will increase the size of the Hadley Cells (again, this has already been observed, so while it's not carved in stone, it looks to be true and hard to argue). This means that those deserts will expand... the intervening arid areas will be larger. It also means that some places that used to get seasonal rains will not any longer, while places that didn't get them (i.e. were just outside the Hadley Cell at the right time of year) suddenly do see that precipitation. Spend some time reading up on it. It's a fun subject, and helps to move one beyond the too simplistic "an increase in rainfall due to increased moisture" point of view. It's obviously not that simple, and scientists are aware of it, even if we ourselves are not (always). Very interestingly, two regions of the earth that will be subjected to climate change through this rather easy to understand mechanism (Hadley Cell expansion) are Australia and Texas, who are both in a way "big players" in climate denial.
82071. Robert Murphy at 03:20 AM on 19 June 2011
       Hansen's 1988 prediction was wrong
       Disregard my above post, I misread the column from the Realclimate link. :)
82072. trunkmonkey at 02:52 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       Chris @ 33 I found downloadable Kent and Muttoni PDF some weeks ago by googling it. I was very skeptical of this notion at first because in classic plate tectonic theory carbonate sediments are too light to be subducted and are scraped off at the continent/arc margin. It now appears that within the last decade or so various isotopic analyses indicate that there are both low and high sediment flux trenches.I have not yet found any remotely articulate explanation for what feaures (angle?)might account for the difference. Tethys is thought to have been shallow and at first glance seems an excellent candidate for substantial carbonate sediment buildup. Closer analysis reveals that the Tethys ocean floor was extremely active, with two spreading centers through most of the Mesozoic. Much carbonate sedment may have already beern subducted or scraped off prior to India's excursion. Unfortunately there is no modern tectonic analogue. There is, however, active rifting going on today in the Red Sea and the Gulf of California.If Lee Kumps "baking carbon rich sediments and perhaps even some coal and oil near the surface."is to be taken seriously, we should see carbon anomolies in these areas. Apparent polar wander paths indicate that the rifting of Greenland from Europe and America was well under way 80mya in the Cretaceous.
82073. JMurphy at 02:48 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       With regard to snow and cold Winters : From Weather Underground : That it is snowy does not suggest that it is colder. If it gets warmer, it does not mean that we no longer see freezing temperatures in places like Michigan. If it gets warmer there is more water in the atmosphere, and when there is precipitation there will be more precipitation, and if it is below freezing, then that precipitation will be ice and snow. From a climate point of view it is more important to look at snow cover in the late winter and early spring. Is the snow melting earlier? And from this very site : Does record snowfall disprove global warming? And, from the Union of Concerned Scientists : It’s Cold and My Car is Buried in Snow. Is Global Warming Really Happening?
82074. jerryd at 02:27 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       Chris – Yes, by the exogenic carbon cycle, I mean pretty much everything on Earth’s surface within a few meters of sedimentary depth. To be honest, it’s a hard concept to describe rigorously, as I found out on NPR about 15 years ago. When asked what the exogenic carbon cycle is, I think I said something like “well, it’s like if you took all the carbon in the ocean, the atmosphere, and on land including soil, trees, plants, animals and newts and put them in a blender.” [I have no clue why I said newts and blender, but it went across the airwaves, and several colleagues continually poke me on this comment]. Basically, it is all carbon that can exchange on geologically short time scales. The idea of slow (million-year) carbon changes caused by tectonism is certainly plausible. I have not yet read the paper by Kent and Muttoni, but will do so shortly. Rob – Thanks for passing along the Beerling reference. I have not yet seen or read this paper either. It certainly looks very interesting. [Here I think an interesting aside: I know both Dennis Kent and Dave Beerling personally, and appreciate their work very much. They are both top-notch scientists. That I have not read these works, I think, signals the state of the field – it is moving really fast. It was easy to keep up with things regarding early Paleogene climates 5-10 years ago, but numerous papers are now coming out every week. I probably need to do some more reading rather than blogging!]. Anyway, there are several major problems with understanding “early Paleogene” climates (here loosely meaning the time from about 62 to 45 million years ago). One is the “hyperthermal problem” noted in previous posts. How do massive amounts of carbon enter the exogenic carbon cycle quickly (and according to recent papers) repeatedly? Another is the “equator-to-pole gradient problem”. All data consistently suggests that the equator-to-pole temperature gradient was much lower in the early Paleogene relative to present-day. That is, the equator was ~5 °C warmer than today but the poles were ~25 °C warmer than today. Some of this problem is solved by the removal of ice (the albedo effect); some of this problem may lie in the use of proxies for past temperature, namely that many records generated at high latitudes may be biased toward summer temperatures. Even after this accounting, the poles seem too warm (or the equator seems too cold) in coupled climate models for the early Paleogene. Matt Huber has a current paper discussing the problem (http://www.clim-past.net/recent_papers.html). This is where I think Dave Beerling might be correct: trace gases may explain the discrepancy. Sphaerica – Great questions. 1/ All sorts of things are conceivable. However, I think that the geological record is telling us that we do not have an appropriate view for how carbon cycles on Earth’s surface. 2/ Several people have done this (notably Bob Berner at Yale). But, a roadblock hits at the PETM, because it is impossible to explain this event within the context of conventional modeling of carbon cycling. Basically, one needs to invoke an "ad hoc" mechanism for carbon transfer. This may be correct, if for example, the source of carbon came via intrusive volcanism. I am 99% sure, however, that we need to rethink how the global carbon cycle operates over geological time.
82075. dhogaza at 02:22 AM on 19 June 2011
       How would a Solar Grand Minimum affect global warming?
       I suppose (to answer my own question) it will help to tighten the bounds of the minimal change in forcing that's been computed with observations available thus far ... more data will help do so regardless of whether the minimum predicted by some comes to pass or not, though ...
82076. dhogaza at 02:21 AM on 19 June 2011
       How would a Solar Grand Minimum affect global warming?
       

       The solar contribution to warming, if any, will be determined, and any more speculation will have ended.

       How will the next minimum - if it happens as predicted - tell us much more than we've been learning observing TSI over the last several decades, including the several years of the current minimum?
82077. Rob Honeycutt at 02:09 AM on 19 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       MoreCarbonOK... There is an old saying. "If you can't stand the heat..." To be quite honest, these guys are not pushing very hard on you. They're only subjecting you to the very lightest of skepticism that every scientist gets put to when publishing work. If you want to do science as a hobby then you should at least accept some of the pressure that any scientist would expect as routine in their research. Brandishing claims of corruption just doesn't cut it. It's a rather un-skeptical cop out.
82078. michael sweet at 02:08 AM on 19 June 2011
       Speaking science to climate policy
       Ken, Apparently the link I provided for you in 13 did not work for you. here it is again. After you have read the section on thermal inertia and unrealized warming we can discuss this further. It would be better to post your questions on that thread since it is on topic there.
82079. michael sweet at 01:58 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       Eric: Please cite references. It is well known that AGW theory predicts more precipitation in all seasons. During the winter this falls as snow. The last two winters were historically warm see here. There were a few spots in Europe and the US that were below average in temperature, but the entire Earth was hot. Your claim is apparently that your house was cold so therefore the entire Earth was cold. That is not correct. Please provide data to support your wild claims that it was cold and that AGW does not predict more snow in a warming world.
82080. Eric the Red at 01:31 AM on 19 June 2011
       How would a Solar Grand Minimum affect global warming?
       Albatross, The whole solar / sunspot issue may finally be resolved if a grand minimum occurs. The solar contribution to warming, if any, will be determined, and any more speculation will have ended. I am actually a little excited about this, because we can now study the sun's changes in detail.
82081. shoyemore at 01:30 AM on 19 June 2011
       SkS Weekly Digest #3
       When I open the site, the lettering (not just in the titles) is screaming at me in bright red capitals. It goes back to normal when I click on a particular post. Am I the only one :) .. or has John decided to "up the temperature"?
82082. Dan Moutal at 01:28 AM on 19 June 2011
       SkS Weekly Digest #3
       FYI if you need to send a large number of emails and you host is complaining Amazon recently introduced its Simple email service. http://aws.amazon.com/ses/ It is a pain to set up, but seems to work very well once you do so. (At least in my testing of it) And it is fairly cheap.
82083. Eric the Red at 01:26 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       Anne-Marie, While global warming theory predicts an increase in rainfall due to increased moisture, that does not correlate with snowfall. Snowfall is largely contralled by temperature; when the temperature rises above freezinf, the precipitation falls as rain. Historical data supports this. The snowiest winters are, on average, the coldest. The past two NH winters were both colder and snowier than the preceding winters.
82084. newcrusader at 00:51 AM on 19 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       Chris the peak in global temperatures coincides with India colliding with Asia 50 million years ago- The PETM occurred 56 million years ago. See Hansen's book page 153. There was another spike in temperatures about 42 million years ago- not as severe as the PETM. Temperatures and C02 fell for the next several million years until global temperatures reached 3 degrees C above what they where circa 1900. This was about 34.5 million years ago, when C02 fell to 450-500ppm.
82085. Tom Curtis at 00:32 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       Norman @34, the point I was trying to make is that there is no point looking for trends in a detrended data set. In this particular case, the trend that was removed was for decreasing rainfall: The consequence of that has been that while floods in SWWA have almost entirely disappeared, drought has become effectively a permanent condition. Moving from a situation in which you have either a drouht or a flood every three to five years into a situation in which you have drought in four out of five years represents a decrease in variability in the rainfall (which will show up in a detrended graph), but the drying will not; and itself results in a significant increase in extreme conditions relative to the twentieth century average.
82086. Eric (skeptic) at 00:10 AM on 19 June 2011
       Linking Extreme Weather and Global Warming
       In the three lower bullets, the first one, increasing trend in extreme rainfall, seems reasonable and well supported although it shows up mostly in local rain gauges. The second bullet seems to contradict the first and the fact that warmer air holds more moisture. This paper http://journals.ametsoc.org/doi/pdf/10.1175/JCLI-3296.1 shows that drought and a reduction in extreme rainfall (as they defined it) went hand-in-hand. The paper also suggests that the particular Australian drought being studied was due to changes in weather patterns, specifically "This supports the argument that the winter (extreme daily) rainfall decline over SWWA is, at least in part, associated with the upward trend of the Antarctic Oscillation."
82087. Bob Lacatena at 23:51 PM on 18 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       jerryd, Two probably bizarre questions, but: 1) Is it possible that carbon existed in some form prior to the PETM which we no longer see in noticeable quantities today? That is, could there have been some sort of release mechanism which entirely escapes our imagination, exactly because it all "let loose" during the PETM? I have no idea what such a form would be, although I imagine such insights would come from a study of the biosphere in any of the millions of years prior to the PETM (e.g. could a massive die off of plant matter during a previous extinction, combined with a certain predominant climate [dry, wet, hot, cold] have produced a "high layer" of what amounts to fossil fuels, something like peat, but with different properties from peat, and yet more accessible than the coal and petroleum with which we are familiar)? 2) Has anyone ever done a sort of "carbon accounting through the ages" to try to add up and track how much carbon has entered the system at various stages of the earth's existence, and in what quantities in what forms it has existed in the various stages of the earth's existence (atmosphere, living biosphere, decaying plant matter, various sequestered carbon forms, etc.)?
82088. Ken Lambert at 23:16 PM on 18 June 2011
       Speaking science to climate policy
       Michael Sweet #19 I am not confused at all. Thermal inertia has everything to do with heat flow and temperature distribution.
82089. Ken Lambert at 23:04 PM on 18 June 2011
       Speaking science to climate policy
       Michael Sweet #21 "If Hansen's estimate of 1.3 W/m2 is correct we are in for a world of pain." Hansen has upped the aerosol cooling estimate as one of the factors to explain the reduced theoretical warming imbalance ie. 0.9 down to 0.59W/sq.m. I don't recall seeing anything in his paper about raising the warming forcings for CO2GHG which should theroetically be about 1.77W/sq.m for a 390ppmv concentration. Why would this forbode a 'world of pain'?
82090. chris at 22:39 PM on 18 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       newcrusader at 19:15 PM on 18 June, 2011 I wonder whether Dr. Hansen was referring to the raised atmospheric [CO2] levels throughout the Early/Mid Cenozoic (65 MYA to around 40 MYA) onto which the PETM "piggybacked" around 55.5 MYA. There is a very nice theory that this was indeed the result of the remorseless drifting of the Indian subcontinent (to be!) into sub-Asia and the subduction of carbonate-loaded plate beneath the ever-narrowing Tethys sea. The carbonates were driven off as CO2, maintaining a steady high level of [CO2] during this period and warm earth conditions. Once India had "squeezed out" the Tethys sea (around 50 MYA), the "CO2 factory" ceased and was overtaken by enhanced weathering of the Deccan Traps (formed near the end-Cretaceous) as these moved (with the Indian sub-continent) into the warm moist tropical humid belt where basalt weathering was very efficient. By around 33 MYA atmospheric [CO2] thresholds had dropped towards the threshold that allowed polar continental ice sheet formation... Can't find a downloadable version of this fascinating paper: D. V. Kent and G. Muttoni (2008) Equatorial convergence of India and early Cenozoic climate trends PNAS 105:16065-16070 abstract However there is a “Commentary” accompanying their article that summarises their proposal quite nicely here.
82091. Anne-Marie Blackburn at 22:12 PM on 18 June 2011
       Linking Extreme Weather and Global Warming
       Norman

       The claim is that there is 4% more moisture in the air (and this has a very high uncertainty factor and needs above and beyond proof as that moisture is entering and living the air at highly variable rates at any given period). The mountain ranges in US received well above 100% of their normal snowfall. If it would have been 104% then the claim that excessive snow is the result of a small increase in overal moisture levels in the air. When the snowfall is doubled it seems a far stretch that these events can be caused by that slight moisture increase.

       That is not what the article claims. Global warming does not cause extreme weather events, but it increases the odds that such events will take place because of changes in the water cycle (and atmospheric circulation) brought on by rising sea and air temperatures.
82092. Dikran Marsupial at 22:03 PM on 18 June 2011
       Phil Jones - Warming Since 1995 is now Statistically Significant
       MoreCarbonOK So to summarise: All of the professional scientists at NOAA, NASA GISS, UK Met Office, CRU, RSS, UAH (who have relevant qualifications and have studied the data in depth) are wrong and you (who apparently does science as a hobby) are right. If there is a discrepancy in the data, it is at BoM (who collect and distribute the data) not at one of their clients. You apparently have nothing to learn from us (as you have not engaged with any of the constructive criticism so far), but we (in our ignorance) have everything to learn from you. Do you realise how you come across? Do you think anyone will take your analysis seriously having seen your display of hubris here? Most physics departments from time to time have a member of public come along with a proof that Einstein was wrong, or a prototype for a perpetual motion machine, or maths department have someone claim to have a short proof for Fermat's last theorem, or a proof that Godel was wrong etc. You are heading into that territory, please do yourself a favour, doing science as a hobby is something very admirable, but you do need to learn the basics first, and have some humility.
82093. chris at 21:56 PM on 18 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       jerryd at 20:33 PM on 18 June, 2011 Yes that was the point I was making with respect to okatiniko's suggestion (his post #11) that the raised atmospheric [CO2] in the PETM might be a response to raised temperatures (by analogy with the raised atmospheric [CO2] during glacial-interglacial cycles). The numbers (massive amount of raised [CO2] during PETM and the delta 13C excursion) simply rule out that as a significant contribution. The carbon must have come from "without" the exogenic carbon cycle! P.S. By "exogenic carbon cycle" I assume that you mean the "accessible" carbon within the carbon cycle that involves the carbon in the atmosphere, oceans and living things.
82094. Norman at 21:40 PM on 18 June 2011
       Linking Extreme Weather and Global Warming
       28 Tom Curtis The graph you describe in your post is the one I am talking about. Extreme events would be excessive or much lower than normal rainfall. In the early part of the graph there were such extremes, then it seems to settle down for awhile and then extremes show up. Is there a trend in the frequency of the extreme events? Looks like there is not enough data available to make such a claim. A longer time frame is required for such.
82095. Norman at 21:37 PM on 18 June 2011
       Linking Extreme Weather and Global Warming
       #32 JMurphy Mechanisms would help. The claim is that there is 4% more moisture in the air (and this has a very high uncertainty factor and needs above and beyond proof as that moisture is entering and living the air at highly variable rates at any given period). The mountain ranges in US received well above 100% of their normal snowfall. If it would have been 104% then the claim that excessive snow is the result of a small increase in overal moisture levels in the air. When the snowfall is doubled it seems a far stretch that these events can be caused by that slight moisture increase. On Evolution, the evidence is not just in the fossil record. That would be meaningless without the other factor. There is a mechanism for evolution that makes it a valid theory (but still not fact). That mechanism is that DNA is flexible, it can be changed by external forces. If it was a very stable molecule that was higly resistant to change than a mechanism would not exist and another explanation would be required to explain the fossil evidence. In science one makes claims then they propose mechanisms that can explain these claims.
82096. Rob Painting at 21:37 PM on 18 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       Jerryd - thanks for the input. Very much appreciated. I noticed in Zeebe 2009, of which you were one of the co-authors, a mention of trace greenhouses gases in the concluding remarks. Have you read Beerling 2011? Any comments?
82097. JMurphy at 21:20 PM on 18 June 2011
       Linking Extreme Weather and Global Warming
       Norman wrote : "Until you have the complete evidence to state the case it is unscientific to make the claims of certainty and mostly seems propoganda to get uninterested people interested in this issue." Maybe you could provide the criteria that would convince you that Global Warming is affecting the weather ? What would it take to convince you ? And, as a side-line, what is the "complete evidence" that has convinced you as to the validity of Evolution - that is, if you do accept it ?
82098. Norman at 21:05 PM on 18 June 2011
       Linking Extreme Weather and Global Warming
       #26 scaddenp Your point is my point. I do not know if waraming is driving the changes in SAM. I brought the article up because it does not make the claim global warming is the cause nor did it claim it was not the cause. It looked for the root known cause. Further research would be needed to see if global warming played a part. I read articles on the web page daily but rarely post. This point is one that I find most unscientific and it prompts me to post. In the above article the quote "How global warming affects weather parameters" should read How global warming may affect weather parameters. Until you have the complete evidence to state the case it is unscientific to make the claims of certainty and mostly seems propoganda to get uninterested people interested in this issue. May be a necessary action if you believe the world is near doom if action is not taken very soon, but it is not a scientific approach. It is a shock the emotional core approach and it is the very thing that is generating such a wave of denial among the average citizen. People have a natural resistence to what seems like emotional manipulation and react negative to it. When all extreme weather events (including very cold and heavy snow events especially without rigorous proof) are linked to global warming the Public becomes skeptical of the claims and turns of the channel. It does not serve your cause well and creates the very wall you are working to bring down.
82099. jerryd at 20:33 PM on 18 June 2011
       CO2 Currently Rising Faster Than The PETM Extinction Event
       To follow with specific points: Chris: This is not the correct way to think about the problem. The glacial-interglacial changes in pCO2 likely involve carbon redistribution within the exogenic carbon cycle; changes in the PETM (and in our future) likely involve carbon inputs and outputs to the exogenic carbon cycle. In any case, all indications are that massive carbon input during the PETM was a response to external forcing. (And this also hits at the root problem because there is no way to explain this with conventional thinking as to how Earth works). Sphaerica and scaddenp: The idea here comes from Svensen et al. (Nature, 2004). They documented, using seismic techniques, thousands of fluid escape structures in the North Atlantic, which appear to have occurred near the onset of the PETM. Thus, they suggested that instrusive sills converted large amounts of organic carbon to methane, which then escaped from the seafloor. It is a very interesting idea and explains several observations; however, it invokes catastrophism (i.e., essentially an equivalent to all the world’s oil, gas and coal were formed and released within <50,000 years). It also fails to explain the other hyperthermal events following the PETM. Newcrusader: With all deference to Dr. Hansen, this idea makes no sense given the timing. The massive carbon injection at the onset of the PETM happened within a maximum of 60,000 years, and probably less.
82100. Miriam O'Brien (Sou) at 20:28 PM on 18 June 2011
       Linking Extreme Weather and Global Warming
       Camburn @21 said 'Also, the current La Nina was not a strong one, as some have indicated.' I don't know how it rated in your part of the world. This La Nina was extreme in Australia. Many parts of Australia had the wettest summer on record. From the media release from the Bureau of Meteorology: "This most recent La Niña [2010-2011] will go down in the record books as one of the strongest in living memory. It's been nearly 40 years [1975-76] since Australians have witnessed a La Niña event of this intensity," said Dr Watkins. AFAIK global warming is deemed a contributing factor in the amount and intensity of rain here this past few months, amplifying the effects of La Nina.

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