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John Hartz at 08:36 AM on 3 December 2013We're heading into an ice age
@jhnplmr & scaddenp:
I deleted your most recent exchange because it was completely off-topic.
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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.
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chriskoz at 07:26 AM on 3 December 2013How 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?
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jhnplmr at 07:06 AM on 3 December 2013We'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.
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scaddenp at 06:16 AM on 3 December 2013We'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.
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jhnplmr at 06:08 AM on 3 December 2013We'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.
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jhnplmr at 05:45 AM on 3 December 2013We'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)?
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Leto at 05:27 AM on 3 December 2013We'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.
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jhnplmr at 04:58 AM on 3 December 2013We'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.
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Dikran Marsupial at 04:31 AM on 3 December 2013We'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.
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jhnplmr at 04:03 AM on 3 December 2013We'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.
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jhnplmr at 03:43 AM on 3 December 2013We'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.
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jhnplmr at 02:35 AM on 3 December 2013We'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.
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.
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Rob Honeycutt at 02:30 AM on 3 December 2013Climate 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.
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Jeff T at 01:16 AM on 3 December 2013It'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.
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CBDunkerson at 23:20 PM on 2 December 2013We'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.
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Dikran Marsupial at 21:38 PM on 2 December 20134 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.
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Videre at 20:26 PM on 2 December 2013No, 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.
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Tom Curtis at 17:05 PM on 2 December 20134 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.
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jeannick at 13:45 PM on 2 December 2013It'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
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chriskoz at 13:41 PM on 2 December 20132013 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
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Antarcticice at 12:56 PM on 2 December 2013Climate 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.
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chriskoz at 12:38 PM on 2 December 2013What 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!
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chriskoz at 12:35 PM on 2 December 2013What 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
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Rob Honeycutt at 10:46 AM on 2 December 2013We'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.
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scaddenp at 08:18 AM on 2 December 2013We'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
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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!
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John Wise at 06:34 AM on 2 December 2013Climate's changed before
Glen Tamblyn
Thanks for taking the time to provide such interesting and useful information.
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BaerbelW at 05:20 AM on 2 December 2013What 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.
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mdenison at 05:01 AM on 2 December 2013What climate denial has learnt from tobacco denial
william #3 - Yes they do. Try sourcewatch
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william5331 at 04:22 AM on 2 December 2013What 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.
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Tom Dayton at 04:00 AM on 2 December 2013We'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.
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jhnplmr at 02:27 AM on 2 December 2013We'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.
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jhnplmr at 02:02 AM on 2 December 2013We're heading into an ice age
327 HK
"What scarcity?"
Fossil fuel depletion is as controversial as global warming!
Here are some estimates:
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.
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Tom Dayton at 01:25 AM on 2 December 2013We'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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jhnplmr at 01:10 AM on 2 December 2013We're heading into an ice age
#321 HK
"As you see, the insolation will decrease only marginally during the next 2-3000 years before it start increasing again"
I agree, my graph shows the same, it should, we used the same data except that I calculated 65N as the mean of 60N and 70N to get one graph. We also seem to agree now that the minimum will occur in 2000 years time.
"AGW has not only stopped the long-term cooling trend that culminated with the Little Ice Age, but has already brought the global temperature back to the level of Holocene optimum 5-8000 years ago."
This presupposes that present levels of GHG will be maintained, my contention is that they will decrease as the fossil fuel scarcity starts to bite in the next few decades. Solar insolation will continue to fall, albeit by not very much, dragging down the temperature with it. After the minimum is passed temperatures will rise again, hopefully at GHG levels far below the present.
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Tom Dayton at 00:50 AM on 2 December 2013We're heading into an ice age
jhnplmr, after you read the Global Warming: Not Reversible but Stoppable post, you should read A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios. Skip past the first section.
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Tom Dayton at 00:26 AM on 2 December 2013We're heading into an ice age
jhnplmr wrote "This presupposes that present levels of GHG will be maintained, my contention is that they will decrease as the fossil fuel scarcity starts to bite in the next few decades."
jhnplmr, you keep repeating that contention without responding to the factual counterpoints that a bunch of people have been making. For example, I pointed you to a peer-reviewed study in the original post that this very thread is on, showing the tiny temperature consequence of a 1 W/M^2 drop in global (not just at 65N) insolation. You could have gotten more details at the link provided in this original post, where you would have read that even in the optimistic greenhouse gas emissions reduction scenario A1B temperature would continue rising well past the year 2100.
I and other people have given you data showing that just the quantity of greenhouse gases that already are in the atmosphere are sufficient to prevent cooling to pre-industrial levels for at least many decades, and that's if all emissions instantly went to zero, which has a probability of zero. Reducing CO2 levels takes much, much longer than raising them (the "long tail"), so every single year that we keep increasing levels means we are delaying their dropping back by about ten years. See the SkS post "Global Warming: Not Reversible, but Stoppable."
You seem to be intentionally missing the point of the example that a single chlorofluorocarbon factory could delay the next glaciation indefinitely. That example illustrates how little greenhouse gas emission is needed. We don't have to use chlorofuorocarbons. We could use a larger amount of CO2, but an amount that still would be trivial to produce, even when fossil fuels become much scarcer.
The bottom line is that your contention is factually incorrect, that preventing cooling would be expensive and difficult.
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We're heading into an ice age
jhnplmr:
"This presupposes that present levels of GHG will be maintained, my contention is that they will decrease as the fossil fuel scarcity starts to bite in the next few decades."
What scarcity? According to this figure from James Hansen’s Climate Change and Intergenerational Justice (not yet published) the reserves are huge, particularly of coal and unconventional gas. If the estimates of recoverable resources (>12,000 gigatons of carbon) are approximately correct and half of that was released at once, it would raise the CO2 concentration by 3000 ppm. If it was released gradually and the airborne fraction remained close to 50% (not very likely) we are still talking about 1500 ppm in addition to the 400 we already have.
If that happened, the CO2 level would remain above 600 ppm for 5000 years, enough for a complete melt-down of Greenland and West Antarctica and maybe East Antarctica as well.
You can test it out for yourself with the GEOCARB model. If you set the transition CO2 spike to 3864 gigatons, the simulation will start with 1900 ppm CO2 in the atmosphere. -
Rafael Molina Navas at 21:39 PM on 1 December 2013Debunking 97% Climate Consensus Denial
joeygoze @ 3
Not a "silly question", just a tricky one.
I would answer: keep in mind that, f.e., energy required for ice melting and due to GHGs (our "contribution") does not increases temperatures ...
You also have an explanation from "skepticalscience":
"... Most studies showed that recent natural contributions have been in the cooling direction, thereby masking part of the human contribution and in some cases causing it to exceed 100% of the total warming".
http://skepticalscience.com/graphics.php?g=57 -
jhnplmr at 19:56 PM on 1 December 2013We're heading into an ice age
# 320 Tom Dayton
"we could prevent a glacial period with a single chlorofluorocarbon factory for the entire world"
You surely don't advocate such a method, it would have a catastrophic effect on the ozone layer. The manufacture of such compounds has been phased out by the Montreal Protocol.
"But as other people already have told you, our greenhouse gas increases to date with just the next couple of decades will be sufficient to prevent cooling, let alone glaciation, for thousands of years"
This presupposes that present levels of GHG will be maintained, my contention is that they will decrease as the fossil fuel scarcity starts to bite in the next few decades. Solar insolation will remain unchanged, the present level (426.76W/m2) was sufficient to reduce ice core temperatures 4 deg C below current levels at a similar point in the cycle 115,000 years ago.
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jhnplmr at 19:32 PM on 1 December 2013We're heading into an ice age
#318 Rob Honeycutt
"Um. I'm sorry but how do you come to the conclusion that global temperature has, in any way, stabilized?"
I sent you my graph showing that ice core temperatures over the last 6000 years had remained relatively constant, naturally there have been oscillations during this period, you can see them on the graph but the long term mean temperature has remained constant. This view is supported by this wikipedia extract Quaternary_glaciation:
"The present interglacial period (the last 10,000 to 15,000 years) has been fairly stable and warm, but the previous one was interrupted by numerous frigid spells lasting hundreds of years. If the previous period was more typical than the present one, the period of stable climate in which humans flourished—inventing agriculture and thus civilization—may have been possible only because of a highly unusual period of stable temperature."
Wiki goes on to cite a scientific paper AgOrigins.pdf which postulated that the development of modern agriculture was only possible due to the relatively stable climate during the present interglacial.
I might add that Vostok temperature over the last 50 years is only 0.2deg C warmer, last_50_yrs.html, a rise of 0.04deg C/decade.
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jhnplmr at 19:11 PM on 1 December 2013We're heading into an ice age
#317 Rob Honeycutt
"Your claim is that Milakovitch cycles vastly overwhelm the radiative forcing of atmospheric CO2 (100w/m^2 vs 2.3w/m^2). That is a "fantastical claim" because it clearly does not square with the vast body of research."
I went on to say that the temperature had remained relatively constant over the last 6000 years so the comparatively large fall in solar insolation was balanced by the relatively small rise in CO2 forcing. This implies that the two rates of forcing were equal despite their numerical inequality.
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chriskoz at 11:07 AM on 1 December 20134 Hiroshima bombs per second: a widget to raise awareness about global warming
I back up Tom@45. Although I disagreed with him at the begining of this discussion (i.e. the widget is directed at non-scientifically literate public therefore its subtext accuracy does not matter); in retrospsct, Tom's suggestion in the last two paragraphs reconciles the issue and add value to the widget. Specifically, those people previously ignorant on AGW and victims of "warming has stopped in ..." myth, looking at the widget, they find not only the myth debunked but also learn more about "bad" vs. "good" or "useful" vs. "destructive" forms of energy, depending on the energy entropy, and why the GHG energy is bad not within microseconds but on the long term, straight from the widget.
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Brian Purdue at 10:24 AM on 1 December 2013Attacks on scientific consensus on climate change mirror tactics of tobacco industry
correction
parent = patient
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Brian Purdue at 09:38 AM on 1 December 2013Attacks on scientific consensus on climate change mirror tactics of tobacco industry
Poster
Meteorologist Vs. Climatologist
This is equivalent to a podiatrist saying there is nothing wrong with the parent’s little toe while an orthopaedic specialist’s diagnosis is the parent’s whole leg has bone cancer.
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Tom Dayton at 09:29 AM on 1 December 2013We're heading into an ice age
Perhaps, jhnplmr, your gross overestimate of the effect of insolation decrease specifically at the 65N latitude is due to your misunderstanding of how glacial eras are started and ended. You seem to think that the relative decrease in insolation at that latitude is the sole trigger for glaciation. So you think glaciation will be triggered when the decrease from the previous insolation maximum nears the corresponding relative amount of decrease that happened at the initiation of the previous glaciation. But that is not how it works. Absolute, not just relative, temperature must be low enough to cause substantial increase in ice and snow cover, for the increased aledo to feed back, reducing the temperature, so the oceans start to absorb more CO2, feeding back to increase cooling, and so on.
If the temperature is high for any reason--hmmm, let's say high levels of CO2--ice and snow cannot increase enough to start that feedback. And if the oceans already are pretty close to their capacity for absorbing CO2, decreasing their temperature a smidge will not pull enough CO2 out of the atmosphere to make enough of a cooling feedback. And if there is a lot of CO2 in the atmosphere, the oceans will have to absorb far more than they did last time, for the absolute temperature to get low enough for the ice and snow to increase.
For some background, see the SkS post on Shakun's 2012 study of the CO2-temperature lag.
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barry1487 at 09:10 AM on 1 December 2013We're heading into an ice age
jhnplmr
"You look upon the contribution of AGW as completely negative"
Here you have assigned to me a standard contrarian talking point that completely misses the point I actually made.
No one is opposed to a slowly changing global climate. The concern is rooted in the pace of change. It wouldn't matter if the cause was anthorpogenic or natural. But it so happens that current human activity could cause a rapid change in global climate, the likes of which have caused massive disruptions to the biosphere in the gelological record.
If AGW caused global climate to change at the same rate as glacial transitions, no one would care.
I'm repeating this so you get it. It's not the change, it's the rate of change that is the concern. Our civilizations have flourished during a period of relative stability, the current interglacial. Now we are landlocked with huge populations dependent on hydrological and agriculatural infrastructure that are at risk from a changing climate. Large populations live and work near the coast and now the seas are rising. If they rose slowly we might be able to adapt with little pain. But if the climate changes rapidly, if extreme weather events become more numerous, if the sea eats into our coastlines displacing millions of people and destroying agricultural industries (the rice farms around the low-lying Mekong Delta feed millions in Asia), if floods drown our grain, drought starves our soil, more hurricanes wreck our homes and workplaces, and the changing climate uproots millians of people, we are in for a world of pain.
We don't want to stop the climate changing, we'd just prefer it changed at a natural pace.
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We're heading into an ice age
jhnplmr:
I used data from the files bein1.dat and bein11.dat and created this graph showing the July insolation for 60oN and 70oN between 25,000 years ago and 25,000 years into the future. As you see, the insolation will decrease only marginally during the next 2-3000 years before it start increasing again.
AGW has not only stopped the long-term cooling trend that culminated with the Little Ice Age, but has already brought the global temperature back to the level of Holocene optimum 5-8000 years ago. A popular denier argument is that northern Europe and Arctic was considerably warmer at that time than today, but that only proves that the reason for the warming was regional, not global, although some of the feedbacks had a global impact. As this graph on RealClimate shows, the global difference between Holocene optimum and LIA was not more than 0.6-0.7oC while the Medieval warm period was just a speed bump on the long-term cooling trend.
So, the next ice age has been postponed for at least some tens of millennia, maybe several hundreds!
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Poster9662 at 07:52 AM on 1 December 2013Attacks on scientific consensus on climate change mirror tactics of tobacco industry
My apologies Fergus Brown. I should have included the link to the paper I referred to in my post of 07:44. The URL is http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-13-00091.1.
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