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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 40251 to 40300:

  1. We're heading into an ice age

    #349 HK

    If you want to duplicate the graph I displayed on #339 you will find the temperature data on edc3deuttemp2007.xls.  This gives EPICA Dome C ice core temperature differences from the 1000 year mean temperature (col 5).  The age of the sample is given in col 3.

    The Jul 65N Milankovitch data was drawn from orbit91 for the years BP and the data for the 10,000 years into the future was derived from the mean values of Jul 60N and Jul 70N in bein11.dat.  A correction factor had to be used for the future years to give the same zero year point.  I used 0.479775 instead of 0.4843 to convert langleys/day into W/m2.  This gives an error of less than 1% in the absolute data but does not effect the date of the minimum point.  I used the formula "=PRODUCT(AVERAGE(DV15:DV16),0.479775)" on my spreadsheet where DV15 and DV16 are the cells holding the relevant data.  The location of these cells will obviously alter as you go down the spreadsheet but *intelligent copying" will make this easier.

  2. We're heading into an ice age

    "Response:[RH] Fixed image width.

    What should I do next time I use an image?

    Response:[JH] Keep your graphic width to 500 pixels or less."

     

    Wouldn't it have been easier to say this in the first place?

    Moderator Response:

    [JH] Lose the snark or lose your posting privileges. No more warnings.

  3. How do meteorologists fit into the 97% global warming consensus?

    I think we can learn something from meteorologists. They use models of the earth’s physical weather systems to forecast the future. 20 years ago I wouldn’t believe a weather forecast for more than one or two days ahead – but now in most situations we can rely on the basic forecast over 5 days to a week. Meteorology is an older science that climate science – but the adjusting of models to make better predictions in common to both, including the knowledge and experience of how we should use the modeling results when we know we don’t have all the factors yet in our software. Our Climate science models are mostly slight variations around what we know at present (the scientific consensus in the climate science anno 2013). And they all fail in some degree, indicating that we havn’t included all the factors in the correct way yet. Small wonder – it’s a vast subject and we have lots to learn. I expect that in 10-20 years our climate models will be very much better and we will look back and think how little we knew in 2013.

  4. What climate denial has learnt from tobacco denial

    You've got to love it when Mr. Boehner goes after the wrong strawman about co2 being a carcinogen. Clearly he forgot for a moment that it was doubt about co2 and climate change, not tobacco and lung cancer, that he was supposed to be spreading.

  5. How do meteorologists fit into the 97% global warming consensus?

    Tom... I'm sure that's a reprint restriction put on Dana by the Guardian. 

  6. How do meteorologists fit into the 97% global warming consensus?

    I am wondering why we are requested to follow a link to the Guardian to read to the end of the article?  The end, reproduced below, hardly seems a sufficient addition to the article to warrant inserting the link rather than just finishing the article:

    "This is also evident from the fact that meteorologists with more climate expertise are more likely to accept human-caused global warming. According to this study, the relatively low level of consensus across all AMS members is due to a combination of factors: lack of awareness of the expert consensus, political bias, and lack of climate expertise.

    In any case, the 97 percent expert consensus on human-caused global warming is still a reality."

  7. How do meteorologists fit into the 97% global warming consensus?

    In my experience, "Tory" is the more common derogatory epithet, as in "Tory Blair" directed at a New Labour Prime Minister. "New Labour" as a derogatory epithet is falling out of use, but not yet archaic.

    Moderator Response:

    [JH] Let's shut this down. It's off-topic.

  8. How do meteorologists fit into the 97% global warming consensus?

    If they are member/voter of Conservative, then how is the term a derogatory epithet?(unlike calling someone mildly centre left a commie, or someone mildly centre-right a facist).

  9. How do meteorologists fit into the 97% global warming consensus?

    Chrizkos.   Conservative is a noun and refers to a political party (or a member of that party) that is to the centre right of politics.  Often Conservsative is used as a derogatory epithet by those to the political  left of centre to denigrate those with whom they disagree. The word conservative is an adjective used to describe those who are inclined to accept the status quo and are not entirely comfortable with change

  10. 2013 SkS Weekly Digest #48

    Nothing, even 'In the Works' on the new Nature Geoscience study on Arctic sea bed methane emission rates being revised upwards by a factor of 2+? Even though RealClimate, Arctic Sea Ice Blog are discussing this important paper?

    Chriskoz does a good job of nutshelling Archer's points, but there's much more to discuss on this one.

    I'm a bit busy, but I could try to summarize the various positions briefly in the next couple days, if you like.

    Moderator Response:

    [JH] If you wish to write a draft article for posting on SkS, you should contact John Cook via the "Contact Us" link found on the bottom of this page. 

  11. How do meteorologists fit into the 97% global warming consensus?

    Chemware... And that was a quote made over a discussion of Relativity when it was a brand new theory. It was the scientific world grappling with understanding this dramatic and profound new theory.

    Greenhouse gas theory is now about 150 years old. The same grappling around took place about 100 years ago promarily between Angstrom and Arrhenius. It was determined about 75 years ago that Angstrom was wrong and Arrhenius was right.

    Since then science has, as with relativity, been refining its understanding of the theory. 

    Discussion of the current consensus on AGW is merely a way of weighing the relative risks involved with continuing to emit massive amounts of greenhouse gases into the atmosphere. As in: Are you willing to bet the future of humanity on the position of 3% of scientists or 97% of scientists?

  12. How do meteorologists fit into the 97% global warming consensus?

    The "debate" over consensus reminds me so much of Einstein's comment on the debate over General Relativity:

    "THIS world is a strange madhouse. Every coachman and every waiter is debating whether relativity theory is correct. Belief in this matter depends on political affiliation."

  13. We're heading into an ice age

    JH: Fair enough.

    jhnplmr: I have replied on a more appropriate thread.

    Moderator Response:

    [JH] Thank you.

  14. CO2 limits will harm the economy

    jhnplmr said on inappropriate thread:

    "Nuclear, wind, solar and tidal?

    I agree, while it takes less energy to get it out of the ground than you can get from it they (we) will continue to use it. I'm afraid that it is very difficult to get people to stop heating their homes, using computers, electric lighting and their cars. It isn't going to happen while fossil fuel supplies are available. Any government that tried to ban their use would get voted out of office."

    Which is why there is such interest in carbon taxes, pigovian taxes, trading schemes. These effectively add the environmental cost (which isnt paid for in mining) to coal cost so that other energy sources become competitive. More acceptable to right-wingers (hey Milton Friedman thought costing externalities was acceptable), than just banning new coal fired stations.

    Bottom line though is that you will pay more for kWh of energy in the future. Beats paying the costs associated with very rapid (ie faster than glacial cycle) climate change though.

  15. We're heading into an ice age

    @jhnplmr:

    Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

    Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.

  16. We're heading into an ice age

    @jhnplmr & scaddenp:

    I deleted your most recent exchange because it was completely off-topic.

  17. We're heading into an ice age

    This guy isn’t particularly worried about the next glaciation. He claims that it’s unlikely to start until the summer insolation at 65oN approaches the same level as the onset of the last glaciation. That means in 130,000 years at the earliest and maybe not until 620,000 years. Note that it takes a much lower insolation to start a glaciation than to sustain it as soon as the slow positive feedbacks have been set in motion. That’s why much of the last glaciation endured through higher insolation than today without ending.

    I adjusted his figure 3 to sum up his arguments:

    Moderator Response:

    [RH] Reinserted image to fix formatting error.

  18. How do meteorologists fit into the 97% global warming consensus?

    I don't comment on The Guardian, so I post my question here.

    In The Guardian Comments, user PearOfAnguish raises the issue of distinction between Conservative and conservative. Can anyone with UK background explain the distinction and why it is important in the context herein?

  19. We're heading into an ice age

    347 scaddenp

    "Rising petrol prices will usher in electric vehicles, also good as far more efficient, but the electricity to drive them comes from what? "

    Nuclear, wind, solar and tidal?

    I agree, while it takes less energy to get it out of the ground than you can get from it they (we) will continue to use it.  I'm afraid that it is very difficult to get people to stop heating their homes, using computers, electric lighting and their cars.  It isn't going to happen while fossil fuel supplies are available.  Any government that tried to ban their use would get voted out of office.

    Moderator Response:

    [JH] This discourse with scaddenp has gone off-topic. Please continue it elsewhere.

  20. We're heading into an ice age

    "These measures, coupled to oil shortages over the coming decade, should help to decrease GHG emissions."

    Should and I certainly hope so. However, China and India are increasing coal use. Rising petrol prices will usher in electric vehicles, also good as far more efficient, but the electricity to drive them comes from what? The USA decrease in coal use is driven by shale gas. When that runs out, coal can increase in a perfectly free market. UK coal closures are driven by economics. My point was that there is no shortage of coal, plenty enough to create serious climate damage. If there is no limitation imposed on usage, and no alternative that is cheaper, then it will be burnt.

    Moderator Response:

    [JH] This discourse has gone off-topic. Please continue it elsewhere.

  21. We're heading into an ice age

    Response:[RH] Fixed image width.

    What should I do next time I use an image?

    Moderator Response:

    [JH] Keep your graphic width to 500 pixels or less.

  22. We're heading into an ice age

    #344 Leto

    "and offers a new inaninty"

    Perhaps you should learn to spell before you start insulting contributors.  Why don't you start by telling me where I am wrong in the deductions I drew from my graph (#339)?

  23. We're heading into an ice age

    By historic values the present levels of CO2 are low compared to those 500 million years ago when they were over 6000ppm Phanerozoic_Carbon_Dioxide. Sea levels were much higher but life was thriving. It has only fallen to current levels (393ppm) over the last few million years.

    Fellas,

    I think it's time to stop feeding this particular troll. He can't possibly be unaware that cities containing millions of people live on the coast. Sure, 'life' will thrive after those cities drown, but that's a facile argument not worth your time, and I doubt even he takes it seriously. He's not here to learn or even think. When you prove him wrong he shrugs it off without acknowledgement and offers a new <snipped>.

    Happy for my comment to be modded out too.

    Leto.

    Moderator Response:

    [TD] I deleted one of jhnplmr's most recent responses, because it went too far into irrelevance and ridiculousness by invoking stellar evolutionary timescale as evidence that our current greenhouse gas emissions are nothing to worry about. 

  24. We're heading into an ice age

    #336 scaddenp

    "And further to peak oil, the climate problem is more about coal than oil, and we have an awful lot of coal available."

    I agree, coal generates more CO2 than oil, but coal usage is falling.  We have closed down the last coal mine in the UK and we are trying to limit its use in power stations in line with our international committments.  These measures, coupled to oil shortages over the coming decade, should help to decrease GHG emissions.

  25. Dikran Marsupial at 04:31 AM on 3 December 2013
    We're heading into an ice age

    jhnplmr 500 million years ago the sun was significantly dimmer than it is now, so higher levels of CO2 were required to avoid a snowball Earth so that life could be thriving.  You need to consider all of the forcings and consider the total energy budget.

    Also just because life was thriving 500M years ago with higher CO2, does not mean that rising CO2 now is not a problem.  The problem with climate change is a lot to do with the fact that it is a change from the climate to which we are heavily adapted (e.g. agricultural practices).

    Moderator Response:

    [TD] jhnplmr, for more information see the rebuttals to the myths "CO2 was higher in the past" and "CO2 was higher in the late Ordovician."  See also "It's Not Bad."  And if you want to argue with those posts, do so in the comments on those posts, not here.

  26. We're heading into an ice age

    #334 HK

    "300 ppm is the highest level recorded in the ice cores during the last 800,000 years before the industrial revolution, so it’s safe to conclude that we have already cancelled the next ice age"

    I agree, the next glacial period is not going to happen, as for the next ice age, we have to get out of this one first!

    By historic values the present levels of CO2 are low compared to those 500 million years ago when they were over 6000ppm Phanerozoic_Carbon_Dioxide.  Sea levels were much higher but life was thriving.  It has only fallen to current levels (393ppm) over the last few million years.

  27. We're heading into an ice age

    #337

    Rob Honeycutt

    "Just stating the same thing when others have presented evidence to show you're incorrect isn't a viable position."

    Now you have given me the link to the graph I was referring to I have a new arrow for my bow.  A picture is worth a thousand words.  Thanks for that!

    I don't know why my post was duplicated, the only thing new is the image.  If this post is duplicated then something has gone wrong.

  28. We're heading into an ice age

    #334 Tom Dayton

    "No. That correlation is "close" only in the orders of magnitude of time and temperature of glaciations, as illustrated by Figure 2 in a Climate Data Information page--even when that figure admittedly has been "tuned" to make the temperature and insolation match as closely as possible"

    Yes, the correlation is close as you can see from my graph, and it is from raw data, not tuned as you suggest.

    Effect of Solar Insolation on the last glacial period

    Look how the temperature rises in response the solar forcing at the start of the last interglacial.  Look how it follows the peaks and troughs until finally we are dragged out of the glacial period into the current interglacial.

    Notice after the peak, 10,000 years ago, temperatures (blue) start to fall in line with the solar insolation but then stop falling and start rising again before they level out and remain relatively constant.  What could have caused this rise and levelling out?  Could it be rising CO2 levels due to man clearing the forests (slash and burn) as he turned from hunting to farming and keeping domestic animals?  The times certainly coincide.  Could it be that the rising GHG from his activities are keeping the cooling at bay despite the falling solar insolation?  If so, then his activities have been beneficial not an unmitigated disaster as you would have us believe.

    If you don't believe that GHG emissions helped to counteract the falling insolation perhaps you can account for the rise and levelling out of the temperatures in some other way?

    "But you do need a climate model more complex than the single-predictor model that jhnplmr insists on using despite the overwhelming empirical evidence of its ineptitude for the application to which jhnplmr is putting it."

    Don't put words in my mouth, I have never said that solar insolation is the only forcing, my very first post on this forum said as much.

    Moderator Response:

    [RH] Fixed image width.

  29. Climate Bet for Charity, 2013 Update

    Antarcticice... Thanks. That's pretty much what I've believed all along.

    In fact, that deniers have been claiming "flat" or "no warming" actually gave me more confidence in the bet. The rate of surface warming is clearly going to change from decade to decade. We're clearly continuing to increase the ratiative properties of the atmosphere. The rate is not going to go negative, it has to flip back and catch up to the long term trend at some point. I'm with you. I think that's going to happen before the end of this decade.

  30. It's cooling

    It seems to me that sea level gives the clearest evidence of continued heating of the earth’s surface. It is possible to estimate the rate of increase of ocean heat content from the rate of rise in sea level. My estimate below is about double the rate determined from ocean temperature measurements in the top two kilometers of the oceans. I haven’t seen a similar computation elsewhere. If someone else has done this before, please let me know.

    The largest contributors to changes in global sea level are heating of the oceans and decrease of Greenland glaciers and Antarctic glaciers and ice shelves. Storage of liquid water on land decreases sea level and extraction of groundwater increases sea level. Storage can have significant short-term effects; but the long term combination of storage and groundwater extraction is modest (See IPCC WG1 Report Chapter 3 p. 318, 2007). Gravity measurements tell us the contribution from Greenland and Antarctic ice. Once we correct the rate of rise of sea level for polar ice, we can compute the rate of ocean heating required to cause the thermal increase in sea level.

    The complication is that ocean heating varies with location and depth and that the thermal expansion coefficient varies with seawater temperature and pressure. See this for the computation of seawater thermal properties. The variation of thermal expansion is greatest for temperatures above 15 Centigrade and very little seawater exceeds 15 C for depths greater than 100 meters. Thermal expansion is small below 10 Centigrade at low pressures, but it increases with either increasing pressure or temperature. We can set an upper limit for thermal expansion at a particular temperature by using the high-pressure value. Nearly all the volume of the Atlantic Ocean is 15 C or colder. With these considerations, we can select the high-pressure thermal expansion coefficient for 12 C as an upper limit to a representative value for the entire ocean. That value is 0.00022 / Centigrade. For comparison, the effective coefficient in Schuckmann 2009 (pre-publication copy) is 0.00017.

    Here are details of the computation:

    The net rate of sea level rise is

    Rn = Rt – G / (So * Dw) = 3.2 mm/yr – 213 Gtonne/yr /(

    Rt = 3.2 mm/yr over the last 20 years

    G = 213 Gtonne/yr over the last 20 years Shepherd et al. (2012)

    So = ocean surface area = 3.6 E+14 m^2

    Dw = mean density of fresh water = 1000 kg/m^3

    Rn = 2.6 mm/yr

    dV = rate of increase of seawater volume = Rn * So

    dV/V = a * dT

    V = total seawater volume

    a = effective thermal expansion coefficient for seawater = 0.00022/C

    dT = mean rate of increase of seawater temperature

    dT = dE/(V * Ds *Cp)

    dE = rate of increase of ocean heat content

    Ds = mean density of seawater = 1030 kg/m^3

    Cp = mean heat capacity of seawater = 4000 Joules/kg/C

    Combining the last two equations, we can eliminate the ocean volume and obtain

    dE = Ds * C * dV / a = Ds * C * Rn * So / a = 1.76 E+22 J/yr = 5.6 E+14 Watts

    The heating rate averaged over the ocean surface area is dE / So = 1.55 W/m^2, twice what Schuckmann gets from temperature measurements. Averaged over the earth’s entire surface the rate is 1.09 W/m^2, which is consistent with the IPCC estimate of net radiative forcing (Climate Change 2007: Synthesis Report, p. 39).

    The greatest uncertainty in this computation is in the effective thermal expansion coefficient. If anything, the value I've used is too large. A smaller value would result in a larger computed rate of heating.

  31. We're heading into an ice age

    The thing that always gets me about fossil fuel reserves is that we know they can't sustain economic growth to 2100. Even if we take the higher figure of 132 years of continued coal use... that is at 2012 levels. Barring a massive decrease in population or economic collapse, electricity use is going to continue to skyrocket. By 2100 it will almost certainly be well over four times 2012 levels.

    One way or another, our fossil fuel use is going to plummet this century. Most children being born now will live to see a low fossil fuel world... which could mean either a transition to clean sustainable energy or a polluted hellscape and massive economic and population crash. Even without AGW and other pollution problems, the need to get off fossil fuels is blindingly obvious... yet somehow there is still fierce resistance.

    Fortunately, solar power is now becoming cheaper than coal for larger and larger portions of the planet. It seems likely that greed will save us from our own stupidity... but we're definitely cutting it close.

  32. Dikran Marsupial at 21:38 PM on 2 December 2013
    4 Hiroshima bombs per second: a widget to raise awareness about global warming

    Tom@47 I don't think the widget in itself is intended to provide a scientific appreciation of the amount of heat involved, just to attract peoples attention to the fact that a stupendous amount of energy has been added to the climate system in a way that makes it easy to appreciate the stupendousness of it.  I think the widget is likely to achieve that quite well.  Once they are interested, they can then find out more about the science, e.g. by reading articles/comments at SkS.

    As for Niagra, I would disagree that this is a non-dangerous example, I for one would not wish to stand uderneath it and be the recipient of some of that potential energy!  Niagra falls is safe if viewed from a safe distance, as is a Saturn V rocket as is an atomic bomb, because the distance protects us from the concentrated release of energy.  It is only a matter of scale, not of substance, because large amounts of energy are always potentially dangerous, unless very diffuse (Naiagra is more diffuse than an atomic bomb, but less diffuse than e.g. food intake). 

    The addition of some information on the harm caused by global warming to date seems a reasonable suggestion, althought the current impacts page is very moderate, which contradicts the idea that the widget communicates the level of harm.

    At the end of the day, there isn't a one-size-fits all approach to communicating science, and not every attempt at communicating science will be to our liking. 

  33. No, Greenland Wasn't Green

    A fairly thorough evaluation of Holocene Greenland temperature history and human migration was published by PNAS in 2011:

    “Abrupt Holocene climate change as an important factor for human migration in West Greenland” William J. D’Andreaa,Yongsong Huanga,Sherilyn C. Fritzb, and N. John Anderson, PNAS ∣ June 14, 2011 ∣ vol. 108 ∣ no. 24 ∣ 9765–9769.

    Abstract: West Greenland has had multiple episodes of human colonization and cultural transitions over the past 4,500 y. However, the explanations for these large-scale human migrations are varied, including climatic factors, resistance to adaptation, economic marginalization, mercantile exploration, and hostile neighborhood interactions. Evaluating the potential role of climate change is complicated by the lack of quantitative paleoclimate reconstructions near settlement areas and by the relative stability of Holocene temperature derived from ice cores atop the Greenland ice sheet. Here we present high-resolution records of temperature over the past 5,600 y based on alkenone unsaturation in sediments of two lakes in West Greenland. We find that major temperature changes in the past 4,500 y occurred abruptly (within decades), and were coeval in timing with the archaeological records of settlement and abandonment of the Saqqaq, Dorset, and Norse cultures, which suggests that abrupt temperature changes profoundly impacted human civilization in the region. Temperature variations in West Greenland display an antiphased relationship to temperature changes in Ireland over centennial to millennial timescales, resembling the interannual to multidecadal temperature seesaw associated with the North Atlantic Oscillation.

    Link: http://www.pnas.org/content/108/24/9765.long

    It is available to the public.  Figures 3 and 4 have temperature reconstructions by several methods and the text discusses the detailed relationship to emergence and decline of various cultures.

     

  34. 4 Hiroshima bombs per second: a widget to raise awareness about global warming

    Dikran @44, I do not think many people realize that the energy of Little Boy was enough to raise 16 million tonnes of water by 1oC in temperature.  Put differently, I do not think many realize that Little Boy had only enough energy to boil dry 71 olympic swimming pools, with an initial temperature of 15oC.  Do we attribute the fact that people do not understand these equivalencies to the fact that they don't understand the scale of energy involved in Little Boy, or in heating water?  This is the problem, IMO, with your argument that people to not recognize the scale of energy in "not-possibly-destructive examples".  People do not recognize the scale of energy involved in Little Boy either, still less in a Hurricane, or an Earthquake.  They just recognize it as a stupendous amount of energy.

    In fact, asked to place on a scale the amount of energy released by Little Boy, that contained in a Hurricane, and that contained in a cubic kilometer of water at 15oC, they will almost certainly get it wrong, showing that they are equating destructiveness with energy.  That being the case, the widget without "not-possibly-destructive examples"  is teaching a lesson about destructiveness, not the lesson about energy you want to teach.

    Further, I disagree that non-violent examples are necessarilly not memorable.  For instance, the Earth's surface is storing 2.4 Niagra-days of energy per second; ie, the potential energy released by an average days flow over Niagra Falls.  I am certain that for those who have seen Niagra Falls, that fact will convey as good a feel for the amount of energy involved as can any single example.

     

    This is likely to be my last post on this topic.  I feel we have canvassed the subject fairly thoroughly.  As you know, or can easilly check, when John Cook first proposed the widget, I was an enthusiastic endorser.  As a result of internal discussions, I moved to a position, first of caution, and then of passionate opposition.  One benefit of this discussion for me has been that I can now see ways in which my objections can be allowed for, making the widget a genuinely class example of science education.

    As mentioned previously, the first change I would recommend is expanding the "impacts" section of the widgets website to include an explicit discussion of the human toll of global warming, but current and potential future.  That page should discuss the tragic fact that with sufficient effort and funding (and not much of either in global terms), almost all the current impacts in terms of lives and disabilities could be negated; but that that will not always be true with BAU.  It should also draw attention to the fact that rellying on adaption in the future is a fools game when we cannot cope with the minimal adaption required now.

    The second change, unsurprisingly, is an additional page explaining the science of energy and entropy.  That page could include some examples of the very large levels of energy stored in ordinary matter as thermal energy, but because the entropy of which is not much different from that in human bodies, are largely harmless - thereby placing the other examples in perspective.

    The third change I would recommend is replacing some of the current widget examples with other examples with more difuse energy.  In particular, the thunderstorm example is particularly good, including as it does much energy at high entropy, but some at lower levels that can cause significant destruction and potential harm (much like global warming).  I think the Niagra-days and Saturn V examples are also good.  Regardless of what is felt about my general point, the Hurricane Sandy example does need to be replaces as it is factually incorrect.

     

  35. It's the sun

    The whole point is about the solar forcing value ,versus the CO2 forcing

    Unless a big volcanic event come to mess things up 

    we should observe the consequences ( or not ) of the very weak solar cycle 24 ,

    it has now just passed its maximum with a very curious double peak .

    solar cycle 25 has everyone guessing,the consensus is a long inter cycle minimum with a record low maximum .

    Should this be the case we will be able to observe and compute the solar forcing

  36. 2013 SkS Weekly Digest #48

    Discussion of the latest methane revelations Shakhova et al (2013) on realclimate by the relevant expert: David Archer.

    Interesting read including comments.

    In a nutshell:

    1. uncertainties too large to have an opinion if CH4 degassing increrased signifficantly in last decade

    2. current best state of knowledge indicates any release of large (measured in Gt) amount will be over 1000s y

    3. no evidence of 50Gt+ "bomb" ready to release within decades has been found, so the "methane scare" is unfounded

  37. Climate Bet for Charity, 2013 Update

    Nature doesn’t play to the Julian calendar, you get different results depending on the start point you use, which is of course why deniers try use 1998 as the start of claimed cooling.

    Use 2011-2020 and you start with a cooler year, but then NOAA has always used the decadal period as the zero years to the 9th i.e. 2000 to 2009 or 1990 to 1999.

    On this long standing measure the 90's where the warmest decade, they were replaced by the 00's, and with 2010 (warmest year on record) we are off to a strong start for the next, yes 2011 was cooler, but compare it to it's equivalent of a decade ago (NASA figures) 2001 (0.52c) above the mean, 2011 (0.54c) or using the NOAA reference point, 2000 (0.4c), 2010 (0.66c), 2003 (0.59c) and 2013?, still in play but looking set to be in the top 6-7 warmest years in the modern record.

    2011/12 where affected by a double La-Nina, that is a seasonal effect, that will pass, 2013 recovered strongly and if that continues and we move from neutral ENSO to an El Nino, then 2014 will be very warm.

    The other factor is the PDO, it has been in negative phase since 2005, it would seem highly likely it will shift before the end of the decade, when it does we will see a spike in temperatures over at least years, depending on the length of the current event and if it lasts only about a decade or is a longer event like the one observed in the 1940’s of course even that event had a reversal in the late 1950’s, but then the current event seems to have had a much reduced influence, we have not seen the dips into cold weather seen in previous events in fact 2005 & 2010 are the warmest years we have seen (even with a negative PDO) and 2008 (which deniers made so much about) is in fact warmer than 1995, which back in the day, was the warmest year in the modern record.

    I'd say your bet is pretty safe.

  38. What climate denial has learnt from tobacco denial

    Ooops, my  post @5 was intended for Weekly Digest #48 thread. I appologise for misplacing it.

    Moderator Response:

    [DB] Could you please repost it on the appropriate thread?  Thanks!

  39. What climate denial has learnt from tobacco denial

    Discussion of the latest methane revelations Shakhova et al (2013) on realclimate by the relevant expert: David Archer.

    Interesting read including comments.

    In a nutshell:

    1. uncertainties too large to have an opinion if CH4 degassing increrased signifficantly in last decade

    2. current best state of knowledge indicates any release of large (measured in Gt) amount will be over 1000s y

    3. no evidence of 50Gt+ "bomb" ready to release within decades has been found, so the "methane scare" is unfounded

  40. We're heading into an ice age

    jhnplmr...  When people challenge your assertions you have to be able to either defend them, showing why you are correctly interpreting the information, or you have to be willing to accept that the challenges are correct and then adjust your position accordingly. Just stating the same thing when others have presented evidence to show you're incorrect isn't a viable position.

  41. We're heading into an ice age

    And further to peak oil, the climate problem is more about coal than oil, and we have an awful lot of coal available.

    "According to BGR there are 1038 billion tonnes of coal reserves left, equivalent to 132 years of global coal output in 2012. Coal reserves reported by WEC are much lower - 861 billion tonnes, equivalent to 109 years of coal output." Source

  42. We're heading into an ice age

    jhnplr:

    Regarding peak oil
    Let’s assume that CO2 will peak at 450 ppm with zero emissions after that. This is a very optimistic scenario since it only takes 20-25 years of our present emissions (no further increase!) to bring us to that point. What will happen?

    In that scenario, according to the GEOCARB model, we will have 350 ppm of CO2 after 300 years and 300 ppm after 4000 years. 300 ppm is the highest level recorded in the ice cores during the last 800,000 years before the industrial revolution, so it’s safe to conclude that we have already cancelled the next ice age!

    And that doesn’t include other man-made GHGs or natural emissions of CO2 and methane from thawing permafrost or methane hydrates. Also keep in mind that in 4000 years the summer insolation in high northern latitudes will be slowly increasing!

  43. Climate's changed before

    Glen Tamblyn

    Thanks for taking the time to provide such interesting and useful information.

  44. What climate denial has learnt from tobacco denial

    william # 3 - There's also the invaluable DeSmogBlog database with a veritable Who-is-Who of climate-misinformers.

  45. What climate denial has learnt from tobacco denial

    william #3 - Yes they do. Try  sourcewatch

  46. What climate denial has learnt from tobacco denial

    Does anyone out there have the energy and sheer bottom to compile a list of climate deniers and their previous denier history such as where they stood on the tobacco question.  An added bit of information would be who funds them including who funds the funders.  This would include MP's and where their campaign funding came from.

    Moderator Response:

    [TD] Starting points are the graphic buttons at the left of this page: Climate Myths From Politicians and Climate Misinformers.

  47. We're heading into an ice age

    jhnplmr claimed he is justified in using insolation at 65N latitude as the sole predictor of global temperature in the next few decades to 2,000 years, because "in an ice age Jul 65N Milankovitch cycles have a close correlation with global temperatures."

    No.  That correlation is "close" only in the orders of magnitude of time and temperature of glaciations, as illustrated by Figure 2 in a Climate Data Information page--even when that figure admittedly has been "tuned" to make the temperature and insolation match as closely as possible.  Just as CO2 is not the only driver of climate, neither is global insolation, let alone 65N insolation.  You don't need a complex climate model to see that, as multiple comments and posts here have made clear.  But you do need a climate model more complex than the single-predictor model that jhnplmr insists on using despite the overwhelming empirical evidence of its ineptitude for the application to which jhnplmr is putting it.

  48. We're heading into an ice age

    #331 Tom Dayton

    "and, bizarrely, you are hyper-fixated on 65N"

    That is because in an ice age Jul 65N Milankovitch cycles have a close correlation with global temperatures.  there is nothing bizarre about it.

    "No sloganeering. Comments consisting of simple assertion of a myth already debunked by one of the main articles"

    The sources I have quoted are widely accepted, my interpretation of them differs from yours.  That doesn't make you right and me wrong, only time will tell.

    "It is asked that you do not clutter up threads by responding to comments that consist just of slogans"

    You are right, this debate is no longer productive.  I have stated my views that AGW has been beneficial in offsetting the falling Jul 65N solar insolation since the last peak 10,000 years ago.  This has served to prevent a fall in global temperatures and has extended the current interglacial period.  I have quoted scientific articles that support this view.  It is up to you to decide if these views have any validity.

    I don't like threats so this is my last post on the subject.

  49. We're heading into an ice age

    327 HK

    "What scarcity?"

    Fossil fuel depletion is as controversial as global warming!

    Here are some estimates:

    peak_oil.html

    Current estimates for the world wide peak production, not only for oil, but also for natural gas, and less traditional hydrocarbon sources range from the pessimistic (ASPO, 2007) to the less pessimistic (Edwards, 2001). The bottom line is that conventional oil and natural gas will probably peak sometime between 2010 and 2040.

    Predicting_the_timing_of_peak_oil

    In 2008, the IEA predicted a plateau by 2020 and a peak by 2030. The report called for a "global energy revolution" to prepare mitigations by 2020 and avoid "more difficult days" and large wealth transfers from OECD nations to oil producing nations.  This estimate was changed in 2009 to predict a peak by 2020, with severe supply-growth constraints beginning in 2010 (stemming from "patently unsustainable" energy use and a lack of production investment) leading to rapidly increasing oil prices and an "oil crunch" before the peak.

    It has been argued that even a "plateau oil" scenario may cause political and economic disruption due to increasing petroleum demand and price volatility

    A 2010 report by Oxford University researchers in the journal Energy Policy predicted that production will peak before 2015.  

    Nicol-André Berdellé adjusted world oil production by deducting the energy equivalent of investments, and concluded that a more than doubling of investment in oil exploration and development between 2005 and 2010, masked a decline in net oil production. He argued that in net energy terms, peak oil has alrady taken place.

    So most agree that peak oil will occur within the next decade, that is of course if the huge increases in reserves reported by most OPEC countries in the 1980's had any foundation in reality.  I think that when supply is unable to meet demand there will be a very rapid depletion as nations stockpile the remaining oil.  Unconventional sources such as shale oil take a lot of energy to extract and we will reach the point where we will put more energy into extraction that we gain from the product.  Fracking has proved successful in the short term but the wells deplete very quickly and it is expensive to drill more.  You point out the huge reserves left in the ground but most will never be extracted due to the energy requirement to extract them.

    We have already closed down the last coal mine in the UK and are trying to minimise our use of coal for power generation in line with international agreements.

    I think that all these factors will result in a decrease in GHG emissions during the next decades.

  50. We're heading into an ice age

    jhnplmr, multiple people repeatedly have shown you data that the insolation decrease you are fixated on (and, bizarrely, you are hyper-fixated on 65N) will have a tiny effect on temperature--an effect too small to worry about for thousands of years, and one that can be offset by a trivial effort to put more greenhouse gases in the atmosphere.

    Your incessant repetition of your contentions without responses to factual counterpoints is sloganeering.  From the SkS Comments Policy: "No sloganeering. Comments consisting of simple assertion of a myth already debunked by one of the main articles, and which contain no relevant counter argument or evidence from the peer reviewed literature constitutes trolling rather than genuine discussion. As such they will be deleted. If you think our debunking of one of those myths is in error, you are welcome to discuss that on the relevant thread, provided you give substantial reasons for believing the debunking is in error. It is asked that you do not clutter up threads by responding to comments that consist just of slogans."

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