Arguments
Recent Comments
Prev 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 Next
Comments 44101 to 44150:
-
John Mason at 23:10 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Yes - I'll be writing a piece about that glaciation before too long. It's one of the most interesting episodes of drastic climate change in the geological record, it coincided with the second biggest mass extinction in the fossil record and the rocks around here record its passing. Indeed the relevant stage of the Ordovician - the Hirnantian - is named after a place not that far from where I live!
-
CBDunkerson at 23:10 PM on 2 July 20134 Hiroshima bombs worth of heat per second
If people don't like Hiroshima bombs you could go with something like 'global energy consumption'. As in, 'global warming is causing the planet to accumulate heat at a rate equal to our monthly global energy consumption every 2 days'.
Most people probably don't have a good handle on just how much energy we use, but it is one of the few other values in the right ballpark to be a useful comparison point. It would also help to dispel the 'global warming is caused by waste heat' myth.
-
Tom Dayton at 22:54 PM on 2 July 20134 Hiroshima bombs worth of heat per second
Glenn and Dana, will y'all please add Glenn's comment as a new section in The Big Picture post? It fills a gap in the logical flow that I've had to fill when pointing people to that post for them to get a very quick basic understanding. I think it is well worth the tradeoff of making that post slightly longer. It would be a new section after the section "Global Warming Continues" and before the section "Humans are Increasing Atmospheric Greenhouse Gases." The section title should be something like "Increased Greenhouse Gases are Causing the Warming."
-
Terranova at 22:30 PM on 2 July 20134 Hiroshima bombs worth of heat per second
John and Dana:
After thinking about this some more, I understand that you are using the analogy of 4 Hiroshima bombs per second to represent the amount of heat gained by the earth as a whole. I don't think it helps the vast majority of even the educated population to understand what is happening. We all know that an atomic bomb is a bad thing. But, on a global scale, is it really?
When you take the surface area of the earth (5.1×10 8 km 2), and the amount of energy received from the sun: the result is that each square meter of area facing the Sun receives about 1,380 joules per second (otherwise known as the Solar Constant). Once you look at numbers on this scale, the numbers produced by an atomic bomb (even 4 per second), aren't scary anymore.
But, everyone knows how bad an atomic bomb is. So, your use of this analogy is an effective tactic.
-
chriskoz at 22:14 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Interesting reading John, looking forward to the next in series.
It's worth adding (I'm not sure if & how well you're going to explain it later) this rock weathering process is also considered to be primary planetary thermostat. That is the balance of the sides of Urey reaction you've shown, is self regulating: e.g. increased rate of rock weathering in response of increased solar forcing, draws down CO2 therfore cooling the planet. The opposite would slow down the weathering, causing CO2 increase from volcanic outgassing, therefore warming the planet.
Such self-regulating properties of these processes are used to explain the "young sun paradox" - the puzzle why Earth maintained relatively stable surface temp during her 4.6Ga evolution despite sun becoming 30% brighter during that time. The answer: weathering thermostat lowered CO2 levels accordingly. The gradual decline of RCO2 on your last figure in Ga timescale can also be thought as said "thermostat at work", because the sun's intensity has increased signifficantly during that time. You can see for example, that Andean-Saharan glaciation at 460-430Ma happened at CO2 levels relatively high, perhaps higher than during early Cenozoic that enjoyed hothouse conditions. That's because sun's output was weaker at that time so glaciation threshold in CO2 was higher.
-
Glenn Tamblyn at 21:51 PM on 2 July 20134 Hiroshima bombs worth of heat per second
arncliffe
Roy Spencer is playing a bit fast and lose with the available data. There are 3 research groups that analyse the data from the satellites. Spencer is one of the principles of one team at UAH. The other teams are at RSS and Star/NESDIS. UAH have been showing a trend of 0.04 C/decade. RSS a trend of 0.078 C/decade. Roy averages these two and shows that average. He doesn't mention Star/NESDIS who are showing a trend of 0.124 C/decade. So if one averaged all 3 satellite results the result would be higher. And in fact it is more accurate to say that the correct value for the satellite data lies somewhere between UAH and Star. If Star is closer to the mark, the models are spot on.
He doesn't mention that the handling by UAH of the troubled transition between the NOAA satellites NOAA-9 and NOAA 10 has been identified as possibly flawed, leading to a cool bias in the UAH data since then.
He doesn't mention that the radiosonde datasets are regarded as questionable for climatological purposes at higher altitude due to radiative heating/cooling effects on the instrument packages.
And then he compares them to model runs based on one of the scenarios with the highest rates of CO2 accumulation.
Finally he doesn't mention that models don't predict exactly what will happen year by year but rather the broad trends. The models aren't good enough to capture all the causes of short term variability. And if you look at his graph, the data for the sensors still falls within the range of model prediction up to around 1998, 2000. So the models may be missing events over the last decade plus. And this isn't an exceptional result. Shorter term climate variability is harder to model, even when longer term trends can be modelled. And a decade is short term in climate terms.
It is a couple of decades too soon to claim that the models are wrong. -
Glenn Tamblyn at 21:27 PM on 2 July 20134 Hiroshima bombs worth of heat per second
arncliffe
" I read for example, that downwelling radiation from CO2 acting as a GHG will only heat the top millimetre of the oceans, but that this is sufficient to alter the heat gradient in that skin and reduce ocean heat loss sufficiently to cause the current warming. Is this hypothesis really credible in the real world of turbulent and wind swept oceans?"
2 scenarios.
- The 'skin' absorbs all the infrared downwelling radiation in the first millimeter and this isn't mixed deeper. The thermal gradient in the skin thus restricts heat loss from the bulk of the ocean below. So the visible sunlight that does penetrate through the skin and warms the ocean to depth is restricted from leaving the ocean again.
- The 'skin' idea isn't valid. Downwelling radiation is absorbed in the top millimeter but then mixing transfers this heat deeper. And as a result the 'skin' doesn't have a temperature gradient that restricts heat loss from the ocean. So the broader ocean absorbs more heat but is more easily able to lose heat as well.
Sounds like swings and roundabouts to me, with the same net result.
-
Glenn Tamblyn at 21:19 PM on 2 July 20134 Hiroshima bombs worth of heat per second
arncliffe
The full body of evidence that GH gases are causing the warming covers quite a range of subjects. However using a very few pieces of information, just simple observations, we can narrow the field of possible explanations for the warming radically.
Ocean warming is occuring at around 8 * 1021 joules per year, or at a rate of around 253 TeraWatts. So a simple question one can ask is 'Where has this heat come from?'. It must have come from somewhere, the 1st Law of Thermodynamics demands that. The largest heat source here on Earth is Geothermal heat, heat from within the Earth, is estimated at around 44 TeraWatts. So the heat accumulating in the oceans is occuring around 5.75 times faster than could be caused by the largest terrestrial heat source. So there is an unavoidable conclusion.
This extra heat isn't coming from anywhere here on Earth. No terrestrial heat source is remotely large enough.
So those two pieces of data have ruled out all possible 'internal variability' arguments.
The heating must be being caused by the Earth being in an energy imbalance with Space. Some combination of an increased amount of sunlight being absorbed by the Earth and decreased amount of Infrared Radiation being radiated to Space.
Next piece of evidence is that the Sun hasn't been warming recently. The Sun has been under virtually constant observation since the mid 70's. Apart from it's normal 11 year cycle, its heat output hasn't been increasing. If anything it has cooled very slightly. So it isn't more sunlight.
Could it be that more of the sunlight reaching the Earth is being absorbed? Around 30% of the sunlight that reaches the earth is reflected back to space and isn't absorbed. So if that percentage had dropped, perhaps due to less reflective cloud cover or something letting more sunlight through, that would explain things.
Except there is another piece of evidence that rules that out. If the warming was being caused by anything related to the Sun then we would expect to see more warming when the Sun is shining - during the day and in summer. And we aren't. Temperatures have risen as much if not more during nights and winter. Whatever is warming the Earth operates day and night. And that rules out anything to do with the Sun as a cause.
This leaves us with only one physically possible conclusion. The Earth is radiating less heat out to space.
But we know the surface has warmed so the Earth should be radiating more to space, not less!
So something is blocking more of the Earth's radiation, stopping it from reaching Space. And there is only one thing that can do that. The Greenhouse Effect. The size of the Greenhouse Effect must have increased; that is the only conclusion we can reach from the data.
Over a decade ago, when the first analyses of Ocean Heat Content were published showing rising heat content, this data was labelled at the time as 'The Smoking Gun'. The gun is still smoking.
-
Cornelius Breadbasket at 20:34 PM on 2 July 20134 Hiroshima bombs worth of heat per second
EvilDoctorDaddy @ 20
LIKE :)
-
EvilDoctorDaddy at 20:26 PM on 2 July 20134 Hiroshima bombs worth of heat per second
Going back to the original point of the the post i.e. “sticky ideas”. When our local vicar wrote a mildly denial article in the parish magazine I invited him around for a solar powered coffee and an explanation of the science of global warming. We finished our session with a look at some of the graphics from here, starting with the escalator and ending with the change in total heat content.
He asked “how much energy is that?”.
I said “four Hiroshima size bombs”.
He said “every year?”.
I said “every second”.
His jaw dropped...
As an idea it’s brilliantly effective.
BTW, Evil Doctor Daddy is what my kids (3 & 5) call me when I case them around the house...
-
arncliffe at 19:12 PM on 2 July 20134 Hiroshima bombs worth of heat per second
Tom Curtis:
Thanks for your reply, I will read your recommended link with interest. Although my main interest in writing to SKS was the rising OHC issue, your comments on the atmospheric temperature 'pause' were interesting but also highlight a problem I have found in gaining an understanding of climate science: There is now an absolute plethora of both models and data sets and these tend to create a 'pick and mix' facility that can seemingly be used to support or rebut any argument. For example, Dr Roy Spencer has recently published on his site a graph that I haven't seen rebutted anywhere, showing the same models as yours, but plotting the satellite/balloon temperatures of the 'tropical mid troposphere', which currently fall well outside the predictions of any of the models.
scaddenp:
I read as widely as I can, but my questions on rising OHC and the thin cool-skin layer were prompted solely by the above article and earlier ones by Rob Painting and Dana.
Chris G:
In answer the last, offensive, paragraph, I did not say that 'it is necessary for IR to penetrate to a depth in order for depth to be heated' or anything remotely like it. I simply referred to the the thin cool- skin effect mentioned by Rob Painting in his article last week, in which he postulated that it inhibited loss of OHC to the atmosphere.
-
Cornelius Breadbasket at 18:33 PM on 2 July 20134 Hiroshima bombs worth of heat per second
arncliffe @ 6
I am thrilled to see that you are being truly sceptical of both the science and the way that it is reported to the public. I am also from the UK and I agree that many newspapers and broadcasters have recently reported that 'efforts to reduce carbon emissions' have increased energy prices. However, is this really the case or is the increase in energy prices down to factors such as the increasing scarcity of oil in the North Sea and the cost of importing gas? I recommend this link as a helpful balance to much that is written in certain newspapers. There is also a wonderful and well-balanced free publication called Sustainable Energy Without the Hot Air. There is much to be studied on the subject and I hope that you find examining the stories behind the headlines as enertaining as I do!
-
Rob Painting at 18:15 PM on 2 July 2013A Looming Climate Shift: Will Ocean Heat Come Back to Haunt us?
jdixon - it's too long-winded to explain in a comment, but perhaps the most significant consequence is that Earth's rotation causes large-scale rotation in both the atmosphere and ocean - because neither is firmly stuck to the Earth's surface like we are. It's called the Coriolis Effect, and is an 'imaginary force' emedded into equations to solve (describe) the motions of fluids. Hopefully this You Tube video makes this clear, but SkS will have some posts explaining the relevance of this (the Earth's rotation) to deep ocean warming.
-
gogreenindia at 17:43 PM on 2 July 20134 Hiroshima bombs worth of heat per second
I like this information and so good and interstisng. thanks for sharaing.
<a href="http://www.gogreenindia.co.in/global.aspx">global warming news<a/>
-
John Mason at 15:46 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Done :)
-
John Mason at 15:31 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
I see we have some great proofreaders amongst the readership! Many thanks - we'll get this fixed ASAP!
-
nmaif at 14:53 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Oops, the same typo is in the equation below the first.
-
Keith Hunter at 14:53 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Great post. Very informative. There are a couple of minor errors in the first graphic. The calcium ion should have the "2" after "Ca" as a superscript, not a subscript. Also there is no charge on CaCO3.
-
nmaif at 14:52 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
This is a minor point, but I believe there is a typo in the silicate weathering equation above the graphic. The first symbol on the right-hand side of the equation should be Ca (superscript)(2+), not (subscript 2)(superscript +).
-
Chris G at 13:13 PM on 2 July 20134 Hiroshima bombs worth of heat per second
arncliffe,
Perhaps I can offer a comparison that is utterly deviod of math, but large on conceptuallization that will make it easier to see the fallacy of what you have been told.
"...downwelling radiation from CO2 acting as a GHG will only heat the top millimetre of the oceans..."
OK, I think it is save to say that thermal radiation penetrates a rock less than a millimeter. In fact, all forms of energy exchange penetrate a rock less than a millimeter before the transfer becomes internal to the rock. Measure the temperature of a rock in the morning, set it in the shade, and later measure its temperature in the afternoon.
Is the whole rock warmer, or just the outer millimeter?
Does the ocean have more turbulence at the surface than a rock? If yes, then there is more opportunity to transfer energy internally.
Does the ocean have more convective currents than a rock? If yes, then there is also more transfer of energy internally.
Another experiment: Take two well-insulated containers and fill both with cold water. Cover one with a lid, and leave the other exposed to the air. Which warms up faster? If the extra energy in the warmer water did not come from the air, from where did it come?
Ask yourself why you chose to believe information that was so demonstrably jibberish as to say that it was necessary for IR to penetrate to depth in order for depth to be heated.
-
chriskoz at 12:56 PM on 2 July 20134 Hiroshima bombs worth of heat per second
This excellent article by Rob:
How Increasing Carbon Dioxide Heats The Ocean
explains the mechanism of ocean warming via inhibitted OA heat exchange due to skin layer warming in simple terms, and should be a good source for skeptics like Donthaveone and arncliffe. Also see the reference to Gentemann & Minnett (2008) therein.
-
Tom Curtis at 12:38 PM on 2 July 20134 Hiroshima bombs worth of heat per second
Donthaveone resorts to a stupid rhetorical game. He correctly points out that models aren't evidence; but does not take heed of what the evidence actually is. In this case, the evidence is the warming oceans. The models are the best prediction of the consequences of known physical laws and the known increase in CO2 concentration (among other forcings). As it happens, the best prediction of the consequence of known physical laws indicates that an increase in CO2 concentration will, all else being equal, result in an increase in Ocean Heat Content. Therefore the theory predicts that which is actually observed.
Donthaveone's stupid game is to pretend that because models are not evidence, they are irrelevant to understanding whether or not the theory predicts the observed consequences. Nothing could be further from the truth.
-
Dumb Scientist at 11:39 AM on 2 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Thanks to Bob Loblaw for running this new R script on his computer.
We argued in our PNAS paper that it is the low-frequency component of the regional variability that has an effect on the global mean. So although you tried to match the high correlation of the two quantities in the observed, this was accomplished by the wrong frequency part of the variance. [KK Tung]
Linear regression depends on the overall correlations, so a realistic simulation will match that rather than trying to match the correlations at specific frequencies. After you criticized my original simulation's high correlation coefficient, I chose new parameters so the synthetic correlation was slightly below the real value. The low-frequency component of my synthetic N. Atlantic SST already affects the global mean because the 70-year "nature" sinusoid is present in both timeseries.
If you agree with the amplitudes of the noise in your previous example, then we can proceed with this example. Your only concern in this case was that the correlation coefficient between N. Atlantic and global data is 0.64, a bit smaller than the observed case of 0.79. "That looked more realistic but the average correlation coefficient over 10,000 runs was 0.64±0.08, which is too small." I suggest that we do not worry about this small difference. Your attempt to match them using the wrong part of the frequency makes the example even less realistic. [KK Tung]
Let's judge realism by first considering the real timeseries:
In contrast, here are synthetic timeseries using Dr. Tung's preferred parameters:
- Dr. Tung's synthetic correlation coefficient between global and N. Atlantic SST averaged to 0.64±0.08 over 1,000,000 runs, which doesn't contain the real value (0.79).
- Dr. Tung's synthetic global variance is 0.12±0.02°C^2, which doesn't contain the real value (0.07°C^2).
- Dr. Tung's synthetic N. Atlantic SST variance is 0.13±0.02°C^2, which doesn't contain the real value (0.05°C^2).
Now here are synthetic timeseries using my preferred parameters:
- My synthetic correlation coefficient between global and N. Atlantic SST averaged to 0.74±0.06 over 1,000,000 runs, which contains the real value (0.79).
- My synthetic global variance is 0.06±0.01°C^2, which contains the real value (0.07°C^2).
- My synthetic N. Atlantic SST variance is 0.07±0.01°C^2, which doesn't contain the real value (0.05°C^2). However, altering this would violate Dr. Tung's claim that "the regional variance is always larger than the global mean variance". (This counterintuitive result is due to the real data after ~1986, when the N. Atlantic warmed slower than the globe.)
Your claim that my new example is "even less realistic" is completely unsupported. I suggest that we do worry about this "small difference" between the correlation coefficients of your suggested timeseries vs. those of the real timeseries because MLR is based on correlations, and your suggested timeseries' correlation coefficient is so low that the real value doesn't even lie within its 95% confidence interval.
We performed 10,000 Monte- Carlo simulations of your example, and found that the true value of anthropogenic response, 0.17 C per decade, lies within the 95% confidence interval of the MLR estimate 94% of the time. So the MLR is successful in this example. If you do not believe our numbers you can perform the calculation yourself to verify. If you agree with our result please say so, so that we can bring that discussion to a close, before we move to a new example. Lack of closure is what confuses our readers. [KK Tung]
For your preferred parameters, I actually find an even higher success rate. This shouldn't be surprising, because your correlation coefficient is much lower than the real value, which causes the regression to underweight the AMO and thus increases the estimated trend. Your timeseries also have variances that are much larger than the real values, which inflates the uncertainties. Here's a boxplot of your post-1979 trend uncertainties vs. the trends:
The comparable white-noise uncertainty for real data is 0.034°C/decade, which is much smaller than your synthetic uncertainties. If you increase the variances even higher above the real variances, the uncertainties will be so large that you'll be able to claim 100% success. But that wouldn't mean anything, and neither does your current claim.
From your first sentence: "My Monte Carlo histograms estimated the confidence intervals", we can infer that you must have used a wrong confidence interval (CI). We have not realized that you have been using a wrong CI until now. The real observation is one realization and it is the real observation that Tung and Zhou (2013) applied the multiple linear regression (MLR) to. There is no possibility of having 10,000 such parallel real observations for you to build a histogram and estimate your confidence interval! So the CI that we were talking about must be different, and it must be applicable to a single realization. ... [KK Tung]
My original simulation's Monte Carlo histograms estimated the confidence intervals. For comparison, my second simulation also calculated 95% confidence intervals around each realization; these came from the least squares fit using the standard procedure you descibed. Here's a boxplot of my post-1979 trend uncertainties vs. the trends:
The comparable white-noise uncertainty for real data is 0.034°C/decade, which lies within my synthetic uncertainties. The true post-1979 trend lies within the 95% confidence interval only 9% of the time, but this statement doesn't report the best-fit trend or the uncertainties so I think the boxplots and histograms are more informative.
In post 153, you created yet a new example. This example is even more extreme in that the true anthropogenic warming is a seventh order polynomial, from the fifth order polynomial in your original example in post 117, and the second order polynomial in Dikran Marsupial's examples. This is unrealistic since in this example most of the anthropogenic warming since 1850 occurs post 1979. Before that it is flat. This cannot be justified even if we take all of the observed increase in temperature as anthropogenically forced. It also increases faster than the known rates of increase of the greenhouse gases. You decreased the standard deviation of the global noise of your original example by half. You took my advice to have a different draw of the random number generator for n_atlantic but you reduced the variance from your original example. [KK Tung]
As discussed above, these new parameters were chosen to address your concerns about the correlation coefficients and variances of the real vs. synthetic time series. The exponents were chosen so the true post-1979 anthropogenic trend is 0.17°C/decade in both cases.
These are thought experiments, which eliminate real-world complications to focus on the key issue. I'm not suggesting that the real human influence is a 5th or 7th order polynomial. But if your method can detect nonlinear AGW, it should recover the true post-1979 trend in these hypothetical cases.
It's strange that you're disputing the shape of my thought experiment's total human influence. We can easily measure the variances and correlations of the real timeseries (and my preferred synthetic timeseries match better than yours), but you've pointed out that aerosols are uncertain so we can't easily measure the total human radiative forcing. Also, the total human influence on temperature is roughly proportional to the time integral of these total human radiative forcings, so it should grow faster than the forcings.
Our criticism of your original example was mainly that the noise in your N. Atlantic data was the same as the noise in the global mean data. In fact, they came from the realization. [KK Tung]
As you note, I already addressed this criticism by drawing global and regional noises from different realizations. But even in my original example, the N. Atlantic noise wasn't the same as the global noise because the N. Atlantic data had extra regional noise added to the global noise.
Using your exact example and your exact method, we repeated your experiment 10,000 times, and found that the true human answer lies within the 95% confidence level of the estimate 93% of the time. This is using the linearly detrended n_atlantic as the AMO index, unsmoothed as in your original example. If this AMO index is smoothed, the success rate drops to 33%. In our PNAS paper we used a smoothed AMO index and we also looked at the unsmoothed index (though not published), and in that realistic case there is only a small difference between the result obtained using the smooth index vs using the unsmoothed index. In your unrealistic case this rather severe sensitivity is a cause of alarm, and this is the time for you to try a different method, such as the wavelet method, for verification. [KK Tung]
Again, my case is more realistic than yours in terms of timeseries appearance, correlation, variances, and error bars. Ironically, I think my case is more sensitive to smoothing than yours because I took your advice to make the regional noise proportionally larger compared to the global noise. Your global noise (0.2°C) is twice as large as your regional noise (0.1°C) but mine are both equal to 0.11°C, so smoothing my AMO index removes proportionally more uncorrelated noise than smoothing yours. I tested this by setting "custom" parameters equal to mine (with my 7th order human influence, etc.) but with your noise parameters, and observed similar sensitivity to smoothing the AMO index over 10,000 runs.
You casually dismissed the wavelet method as "curve-fit". Wavelet analysis is an standard method for data analysis. In fact most empirical methods in data analysis can be "criticized" as "curve-fit". The MLR method that you spent so much of your time on is a least-square best fit method. So it is also "curve-fit". [KK Tung]
Indeed, that's why I don't think wavelets are different enough from linear regression to provide independent methodological support. Again, attribution is really a thermodynamics problem that needs to be calculated in terms of energy, not curve-fitting temperature timeseries. Your curve-fitting claim that ~40% of the surface warming over the last 50 years can be attributed to a single mode of internal variability contradicts Isaac Held and Huber and Knutti 2012 who used thermodynamics to conclude that all modes of internal variability couldn't be responsible for more than about 25% of this surface warming.
-
Donthaveone at 11:26 AM on 2 July 20134 Hiroshima bombs worth of heat per second
Scaddenp,
So far my comments have been related to Tom @7 in that i do not believe he provided the evidence arncliffe asked for.
Moderator Response:[DB] Again, ScaddenP provided the remainder of the response requested.
Drop it.
-
JasonB at 10:58 AM on 2 July 20134 Hiroshima bombs worth of heat per second
Donthaveone,
arncliffe wrote:
It appears from SKS that rather than the atmosphere currently warming as predicted by the majority of models, it is the oceans that are rapidly heating.
This suggests that arncliffe thinks that the oceans "rapidly heating" is inconsistent with what is predicted by the majority of models.
So Tom responded:
arncliffe @6, all models predict that the ocean will warm.
And went on to prove that claim.
scaddenp then went on to address the issue of how CO2 warms the ocean, as pointed out by DB.
Why do you have a problem with that?
-
DSL at 10:24 AM on 2 July 2013Heartland's Chinese Academy of Sciences Fantasy
Daniel, how many people are included in the category "knowledgeable about climate science"? If you're here at SkS, then you're probably knowledgeable enough about the war of rhetoric surrounding the subject. If so, it's puzzling you'd make such claims. The non-knowledgeable public relies on interpreters and experts to understand the science. They have no other route to the approximation of truth that science provides. Consensus is a powerful rhetorical tool. It's evidence that experts believe a proposition or set of propositions. That's good enough for many members of the non-knowledgeable general public. If it's not good enough for you, why complain about Cook? Why not complain about the social structure that forces most people away from engaging the science?
I find it extraordinary that people like Anthony Watts complain about a study like Cook's when Watts himself relies on a variety of evidence-free rhetorical tools to shape public opinion. The difference between Cook and Watts, of course, is that Cook's position is supported by both the consensus of scientists and the consensus of evidence. Watts is supported by the likes of Willis Eschenbach.
-
scaddenp at 10:20 AM on 2 July 20134 Hiroshima bombs worth of heat per second
If you go to the SoD articles referenced, this is a little experiment off the MV Tangaroa in one of them. As with everything in science, you have a theory/model from which you make predictions, then check it against observations. (ie the temperature and temperature profile of the ocean). Those measurements are empirical. If you propose that increase isnt from CO2, then please provide an alternative model for where the energy in the ocean is coming from? (And an explanation as to why extra thermal radiation hitting its surface is not heating it - the extra radiation is also empirical). Scientists are extremely attached to conservation of energy law.
-
Donthaveone at 10:00 AM on 2 July 20134 Hiroshima bombs worth of heat per second
Tom Curtis @ 7
Arncliffe asked for evidence but all you gave him was computer model simulations.
Moderator Response:[DB] Actually, Tom gave the vast majority of the answer requested with ScaddenP pointing to the rest of the answer.
Please read more and look to provoke less.
-
Tom Curtis at 10:00 AM on 2 July 20134 Hiroshima bombs worth of heat per second
Another easy way to visualize the accumulation of heat is in terms of football fields (Soccer). It takes approximately 71.43 billion Wembley Stadiums to pave the Earth's surface. The average energy gain over the last decade, therefore, equates to illuminating each such Wembley sized area with thirty five 100 Watt bulbs. That is 0.46% of the energy from the 380 2Kw normally used to light Wembley Stadium for night games. It is dubious that it is enough light for the players to see the ball, let alone the fans.
That visualization is not as high impact as the atomic bombs. It is, however, probably more accurate.
The crucial element which makes it more accurate is entropy. Entropy can be most easilly understood as the inverse of relative energy intensity. If you take an amount of energy, and concentrate it in one location it has a low entropy, whereas if you smear it out it has a high entropy. One billion atomic bombs has a very low entropy, but 2.5 trillion 100 watt light bulbs spread evenly over the Earth, and operating for a decade has a very high entropy. Very clearly, the energy accumulation in the Earth system is more like the latter than the former.
The important fact about entropy is that in high entropy systems, it is difficult to extract energy to do work. Put another way, the lower the entropy of your energy source, the more of that energy you can extract to get things done. Atomic bomb explosions have very low entropy. They get a lot of work done, in the form of flattened buildings and lives destroyed. One hundred watt bulbs, in contrast, have high entropy and can accomplish little beyond allowing us to see.
And that is the scientific problem with the atomic bomb analogy. Three percent of the Earth's surface is urban. So, if one billion atomic bombs had actually rained down at random over the Earth's surface over the last decade, then on average 30 million such bombs would have landed in urban areas. Nobody on Earth would be in doubt as to the danger the rain of destruction would represent.
The accumulation of heat due to global warming is also dangerous - but not on that scale. Lives have been lost due to global warming already, and property and economic damage in the billions has been caused almost without doubt. But the destruction is difficult to pick out against the normal background of droughts, heatwaves and destructive weather. By evoking the image of the atomic bomb, we risk triggering peoples "bullshit sensors" because they know that global warming is not yet (and may never be) as destructive as 4 atomic bombs per second raining down on the Earth's surface. Put simply, the image invoked by atomic bombs is that of raw, destructive power; but that image is false as applied to the heat accumulation when quantified in terms of energy alone. Therefore using atomic bombs as a unit of energy is fundementally misleading. We would be better sticking with the raw numbers, however, poorly understood than introducing a sticky, but fundamentally misleading image.
-
scaddenp at 09:45 AM on 2 July 2013Heartland's Chinese Academy of Sciences Fantasy
Why mention it? Because there are large numbers of deliberately ignorant deniers out there claiming that there isnt. That doesnt make the science right but it is the only rationale basis for making policy. The only way to be sure what the published science is saying, is to survey it.
Why not say "Science proves the project"? Well because a knowledgable person knows that you dont have proof in science, only in mathematics.
-
scaddenp at 09:40 AM on 2 July 20134 Hiroshima bombs worth of heat per second
Arncliffe - as to how CO2 warms the ocean, see links where this was recently discussed here. It looks to me like you are getting your information from sites created to misinform you rather than from the science.
-
danieltreed at 09:37 AM on 2 July 2013Heartland's Chinese Academy of Sciences Fantasy
Furthermore, the argument that including one more term mentioned by Tol is then sufficient is also absurd. You have to include a long tail of terms, which could DRASTICALLY change the distribution. And that's just usage of terms.
-
danieltreed at 09:35 AM on 2 July 2013Heartland's Chinese Academy of Sciences Fantasy
@Tom Curtis
You said "no knowledgable person argues that AGW is true because a consensus of scientists accepts it."
Then why does John Cook bother mentioning it?
"I am not sure what you mean by saying "the endorsement graph is refuse". Indeed, such vague negative criticisms indicate only that you reject the study because it is ideologically inconvenient."
Let my criticism be more specific... I will quote YOU:
"No knowledgable person argues that AGW is true because a consensus of scientists accepts it."
John Cook started "The Consensus Project"... if science is on his side, why would he do this? Why not start "The Science Proves It Project", as any "knowledgable" person would to prove "AGW is true." -
Tom Curtis at 09:06 AM on 2 July 20134 Hiroshima bombs worth of heat per second
arncliffe @6, all models predict that the ocean will warm. In a recent study, a group of models set up to the standards specified for the next IPCC report showed a mean Top of Atmosphere energy imbalance of 0.47 W/m^2 when forced by a 1% growth in CO2 concentration per annum, ie, approximately equal to equivalent to the average increase in GHG forcing over recent decades:
Of necessity, those models show most of that warming going into the ocean, for if they did not they would predict rises in temperatures greater than 10 degrees C per decade. That compares with the 0.5-0.6 energy imbalance over the last decade found in recent studies.
Further, all models show "pauses" in surface temperature increase against the background of ongoing global warming. That is a simple consequence of annual variations in temperature equivalent in magnitude to a decades worth of global warming. The presence of an upward fluctuation at the beginning of a period, coupled with a downward fluctuation towards the end can greatly decrease or entirely eliminate the overall upward trend. In models, these "pauses" have lasted up to twenty years with no long term impacts on predicted temperature increases. That is, the presence of a 20 year "pause" at the start of the 21st century has no impact on the predicted temperature of the model in 2100.
Finally, the current so-called pause in temperature increase covers a period starting with one of the two largest known El Nino (short term warming) events known, and ends with two large La Nina (short term cooling) events. Starting with a straight linear trend of 0.2 C per decade (the IPCC prediction), adding in the initial El Nino and just one of the terminating La Nina's results in an apparent linear trend less than that observed over the last 17 years. Further, the current "pause" in temperatures actually shows an apparent linear trend 40% greater (over the last 17 years, gistemp) than the linear trend from 1901 to 2000.
-
arncliffe at 08:21 AM on 2 July 20134 Hiroshima bombs worth of heat per second
I am layman, approaching eighty and admit to a sceptical bent. I live in the UK, where through an aggressive commitment to reduce carbon emissions coupled with plain incompetance, succesive Governments have followed an energy policy that has led to escalating electricity prices and, now, threats of black outs giving us an electricity supply situation akin to that of a third world economy. The carbon reduction element of this catastrophic policy had better be worth it and although I won't be around to see the evidence that it is, or is not, I would like to make my own informed judgement before I kick the bucket. Therefore:
It appears from SKS that rather than the atmosphere currently warming as predicted by the majority of models, it is the oceans that are rapidly heating. I would be interested to know what empirical evidence exists that the increase in OHC is actually caused by CO2 and what the mechanism is. I read for example, that downwelling radiation from CO2 acting as a GHG will only heat the top millimetre of the oceans, but that this is sufficient to alter the heat gradient in that skin and reduce ocean heat loss sufficiently to cause the current warming. Is this hypothesis really credible in the real world of turbulent and wind swept oceans?
-
theelf at 07:48 AM on 2 July 20134 Hiroshima bombs worth of heat per second
Two dozen 1500-W electric kettles continuously operating for every living person on Earth might be even better for the tea-drinking countries.
-
shoyemore at 07:35 AM on 2 July 20134 Hiroshima bombs worth of heat per second
According to Wikipedia, the earth receives 119 x 10^15 Joules of energy per second from the sun, discarding the amount that is reflected. http://en.wikipedia.org/wiki/Solar_energy
The point is: how much of that is retained to drive up the earth's temperature, given the energy imbalance in the earth's climate system (Heat In > Heat Out).
The Wikipedia number equates to 1900 Hiroshima bombs (using 6.3 x 10^13 to be the heat released by a single bomb).
According to the above estimation, only 1896 bombs-worth of energy escapes back to outer space per second, leaving 4 bombs-worth per second to accumulate in the earth's climate system, raising the temperature.
An A-bomb's-worth of energy is an easier unit to imagine than 6.3 x 10^13 Joules, so I am good with it.
Discussing this elsewhere, I used the analogy of an electric kettle heating water - the heating element is pumping energy into the water per second, more than is escaping through the kettle sides per second. Result is temperature rise in the water as a fixed amount of energy accumulates per second.
-
KR at 07:11 AM on 2 July 2013It's cooling
scliu94 - Fun word for the day: the proper term for that particular article, and its author, is mumpsimus. "A view stubbornly held in spite of clear evidence that it's wrong; a person who holds such a view."
-
Terranova at 06:15 AM on 2 July 20134 Hiroshima bombs worth of heat per second
Per antwerpenaar above, I can't help but agree. Can you quantify what that number means? How does the 4 Hiroshima bombs per second relate to the energy received from the sun per second?
-
Antwerpenaar at 05:28 AM on 2 July 20134 Hiroshima bombs worth of heat per second
I'm a non-expert here, but I'm uncomfortable with the Hiroshima Bomb analogy.
1) It gives the idea, quite strongly, that we 'warmists' are just out to scare everyone without any rational basis. A bit like Godwin's law.
2) (And echoing theelf): It doesn't help the reader to place the size of the problem. OK it's scary. And I know that a Hiroshima bomb going off in my living room would be quite dramatic. But what does it mean on the global scale? How many Hiroshima bombs are a degree celsius, for example?
-
sethpeck at 03:57 AM on 2 July 2013BC’s revenue-neutral carbon tax experiment, four years on: It’s working
Great article, definitely need to see these things happening in the USA. Also, I think the phrase "meme...propogated by Richard Dawkins" is a bit of a redundancy, don't you?
-
theelf at 03:33 AM on 2 July 20134 Hiroshima bombs worth of heat per second
John Lyman used the Hiroshima bomb reference with regard to ocean heat in May 2010, during interviews regarding his Nature (2010) study, e.g.:
http://www.livescience.com/6472-study-ocean-warmed-significantly-16-years.html
It is not easy to quanity such a large number as 250 TW in a fashion that is meaningful to people. The anology of each of the 7.1 billion people on the planet continuously running about two dozen 1500-watt hair dryers might also be a useful, although it is hard to imagine 7.1 billion.
-
jdixon1980 at 01:01 AM on 2 July 2013A Looming Climate Shift: Will Ocean Heat Come Back to Haunt us?
Rob Painting @5: "What I'm getting at is that the trends shown in figure 3 are precisely what we would expect based upon the motion of fluids on a rapidly rotating planet such as Earth."
I have a (probably very basic) physics question that has been nagging me since I first read about the early weather/climate simulation experiments with rotating dishpans/concentric cylinders in the Spencer Weart essays: Given that Earth is only rapidly rotating with respect to a non-Earth reference frame, why do things that are on Earth, and have been on Earth for a while, "feel" (i.e., physically act) like they are rapidly rotating? My intuitive sense is that it must have to do with extraterrestrial forces that come from specific locations and directions relative to which the Earth is rotating, like gravitational pull from the Sun, moon, and perhaps other objects, as well as the cycling on and off of irradiation from the Sun at most latitudes. Is this understanding correct, or is there some way that the Earth's "rotation" has an effect unrelated to other objects in space?
-
Mark Harrigan at 00:29 AM on 2 July 2013Media Overlooking 90% of Global Warming
I can't believe I am saying this, as the media covergae of climate change is almost universally appalling BUT I think part of the problem is that we, as the scientific community allowed the message/meme to permeate that media that "warming" was purely an atmospheric temperature phenomena to be assessed solely by average global temperatures.
Some people have trouble counting, a very large number don't really understand what an average is, how to calculate it or what it actually represents. As for a moving average to be messured on, say, a decadal basis - forget it.
And I don't think we scientists have communicated that very well - which is why in part so many still continue to think warming has "paused".
Of course the media has not helped and I do not offer this comment as exculpatory for the media.
But we really need to get better at explaining what "warming" means.
I'm a phsycist - and I remember being highly skeptical about AGW when I first heard about it in the late 80's - reasoning that the ocean was such an enormous heat sink that any impact on atmospheric temperatures would be dwarfed by the impact on increased heat content in the ocean. Well, I was a little bit right.
As I studied the evidence it became clear to me that the issue was real, and that as greenhouse gas levels increased we would see ice mass disappearing and ocean heat content increasing before temperatures rose dramatically.
Yet there was very little of this sort of dialogue in the media. NOR did it feature prominently in the messages given by science.
Now that we know much more than we did about ocean circulation patterns, intermixing and the like (although there is still much to learn) we need to get this message across in much simpler fashion than we have done so far.
For example - this video http://www.colorado.edu/news/multimedia/grace-mission-measures-global-ice-mass-changes could do with more prominence but where is the place one can point to that shows GLOBAL ice mass loss. The best on this site is here (I think) http://www.skepticalscience.com/melting-ice-global-warming.htm - but it's not "simple" enough. We have to reduce the message down to what can be grasped and absorbed quickly. By all means show the detail once we have people's attention but what needs to be understood is the total ice mass loss. because most people can grasp that ice doesn't melt without an injection of heat.
The same with heat content in the ocean. The 90% statistic and the 3-4 hiroshima bombs per second doesn't work - because most people haven't a clue what that means.
We need to translate that into a simple measure - like what would happen if all that excess heat going into the ocean DID get transferred to the atnosphere. Has anyone seen any attempts to produce such a figure?
Or perhaps a thought experiment.
Ask people what they think would happen if we had a large room where 10% of the floor was covered with a large block of ice and a further 70% was occupied by a large tank of deep water at an average temperature of just a few degrees celcius. Assume that the mass of water vapour in the room is about 0.001% of the water in the tank and the ice cube. Further that the total mass of the ice block is about 2% of the mass of water in the tank
We then introduce a modest increase in infrared radiation into the room - at just (let's keep it simple) a uniform 1 Watt/m2.
Where we would notice the effects first? In an increase in ambient room temperature? The ice starting to melt? Or the water starting to gain "heat"?
Or more accurately - where would the (majority) of the heat (energy transfer) go?
I wonder?
-
Tom Curtis at 20:33 PM on 1 July 2013The Climate Show #34: four Hiroshima bombs a second
Chriskoz, it is an article of faith in Queensland that State of Origin is at the center of the universe; and therefore can never be off topic in any discussion. The Ashes are only slightly less important. One of the gravest ill effects that may attend on global warming is the potential cessation of these series due to the collapse of civilization.
;)
-
chriskoz at 19:56 PM on 1 July 2013The Climate Show #34: four Hiroshima bombs a second
John Cook,
You are trying to derail this whole Climate Show. I postulate "State of Origin" and "Ashes" phenomenons you're bringing in, have no relationships with the title of this show, or any relationship is incidential (like number of pirates vs global warming), unless you prove otherwise :)
Back to the topic. In this interview, Bill explains his "Math" based on the number 450ppm CO2, although somewhat reluctantly. Well, I'm bit disapointed because that's in odds with his organisation 350.org: did he already give up advocating 350ppm ?
I know the maths of 450ppm because all media is talking about it: that's the political limit. But the scientific limit, according to Jim Hansen is 350ppm, corresponding to, if I recall well, 1.5C total warming including the Earth system response. That math would be more interesting for me: i.e. how long should we wait, given the fastest possible emission peak and decline scenario, for the ocean to absorb CO2 back down to 350 level, and pray that both GIS and WAIS hold on and other no other feedback is triggered. That's the math I would like to see here...
-
bill4344 at 12:41 PM on 1 July 20132013 SkS Weekly News Roundup #26B
That's right William! Any time something has been identified as a pollutant in the past it's simply been regulated completely out of existence, and all the emitters have been locked up! In iron coffins, with spikes on the inside, to quote Monty Python.
Not so much a strawman, as a strawbogeyman, really... ;-)
-
William Haas at 12:12 PM on 1 July 20132013 SkS Weekly News Roundup #26B
If CO2 is really a pollutant then all emissions should be illegal and all those who emit CO2 should be prosecuted.
-
tcflood at 12:07 PM on 1 July 2013A Detailed Look at Renewable Baseload Energy
Tom Curtis @438,
Please read @432 and you will see that your comments are off topic.
Incidentally, I'm also well aware of the issues you raise.
-
Tom Curtis at 10:59 AM on 1 July 2013A Detailed Look at Renewable Baseload Energy
tcflood:
1) Certain engines are designed for use with particular fuels. In particular, jet engines are designed for use with kerosene rather than hydrogen gas, the two having quite different properties. By extracting CO2 to make hydrocarbons, the Navy will avoid the need to retrofit their fleet of aircraft with different engines.
2) Hydrogen gas is notoriously difficult to store in a compact manner, while compact storage is a necessity in aircraft. So, even in the event that the navy did convert to hydrogen gass for a fuel, it would need to retrofit the fuel tanks of its entire fleet of aircraft - again something unlikely to be practical.
3) Hydrogen gas has the tendency to make hot metals brittle, and brittle turbine fans are a very bad idea in jet engines. This may by itself make hydrogen gas powered turbojet engines impractical.
I don't know enough to know which of these three is the most important factor, or even if they are the only factors. I suspect strongly, however, that the Navy experts do know about the relevant significant of these (and other) factors, and that the Navy's decision is not fivolous. Unless you are reasonably expert in the areas of aircraft fuel storage, jet engine design, and metalurgy, however, I doubt sincerely your ability to formulate reasonable critiques of the Navy's decision. Assuming energy requirements is the only factor certainly does not count as reasonable in this context.
Prev 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 Next
