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Kevin C at 18:33 PM on 3 July 20134 Hiroshima bombs worth of heat per second
While I have enormouse respect for Robert Rhode's work at BEST, the rest of that paper wouldn't have passed review in a climate journal.
"We are not aware of any global climate models that predicted the reversal of slope that we observe."
That's weasel wording for "The diurnal temperature literature looked difficult, so we didn't read it".
There is an extensive literature on diurnal temperature range and it is far more complicated than the BEST paper makes out. DTR does decrease with greenhouse forcing, but is much more strongly influenced by aerosols, clouds, soil moisture and so on, as even two minutes with google scholar will reveal.
To be fair SkS's material on DTR is similarly lacking in nuance - it's on my list of things to fix if we ever get a breathing space between debunking new nonsense. Glenn is correct that in the absence of other factors solar warming would cause an increase in DTR, however the other influences are sufficiently large that we would have to eliminate them to draw a strong conclusion from this effect alone. Drost et al use multiple fingerprints in combination to obtain a much more robust result.
More compelling still is the fact that we can see the increase in greenhouse warming in both the outgoing infrared radiation spectrum, and in the infrared glow looking up at greenhouse gases from the surface. -
Slioch at 17:33 PM on 3 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Silicate rocks are a complex mix of (mostly) silicate minerals. These minerals do not have a fixed composition: in feldspars, for example, sodium, potassium and calcium (and other) atoms can substitute for one another, and the exact composition of the feldspar crystal depends upon both the composition of the melt from which it crystallised and the temperature and pressure at which it did so. Thus, the composition of silicate rocks is more easily and accurately recorded as a list of oxides of various amounts, rather than of minerals per se. For example, a typical basalt lava has the following composition:
SiO2 49.06%
TiO2 1.36%
Al2O3 15.70%
Fe2O3 5.38%
FeO 6.37%
MnO 0.31%
MgO 6.17%
CaO 8.95%
Na2O 3.11%
K2O 1.52%
H2O 1.62%
P2O5 0.45% (from Turner and Verhoogan, "Igneous and Metamorphic Petrology").
Giving the composition of silicate rocks in this way enables one to immediately appreciate their potential for carbon sequestration via weathering, in this case, from the 8.95% of CaO and 6.17% MgO. Another (less common) extrusive igneous rock called rhyolite has only 1.22% CaO and 0.38% MgO and has thus much less potential for carbon sequestration.
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JasonB at 15:45 PM on 3 July 20134 Hiroshima bombs worth of heat per second
I had a quick look and found the claim in the BEST paper here: http://www.scitechnol.com/GIGS/GIGS-1-101.php
Specifically, Figure 4 on page 4 shows a decline in diurnal range from 1900 to 1987, followed by an increase in diurnal range:
The paragraphs above the figure note that "The rise takes place during a period when, according to the IPCC report, the anthropogenic effect of global warming is evident above the background variations from natural causes" and "We are not aware of any global climate models that predicted the reversal of slope that we observe".
Personally, I wouldn't be rushing to point to this as evidence that the current understanding of AGW is wrong.
Firstly, the recent figures don't like look like they stand out with respect to the long-term trend extrapolated forward from about 1970; the steep decline from the late 60s to the mid 80s followed by the rebound back up to the long-term trend is perhaps the portion that needs explaining. Indeed, the steep incline seems to have levelled off again.
Secondly, even with that dip and recovery, there is still an overall decline on longer time scales, exactly as expected. Although BEST are fairly confident in their results as shown by their uncertainty estimates, I think they are talking about the uncertainty in the true value, not the uncertainty introduced by short-term fluctuations about the trend. The highly "certain" dip and recovery could well be a highly certain natural variation that is in no way unusual (the uncertainty in the earlier figures makes that hard to determine) and it could be that, in fact, there was no change in the long term trend underlying that natural variability. (In other words, even if the monthly anomalies reported for GISTEMP, for example, were accurate to 0.00001 degrees, it wouldn't change the fact that we'd need well over a decade of readings to ascertain the long-term trend, because the variability is real feature of the system and not simply a measurement error.) Since temperature readings are affected by more than just CO2, it's possible that the diurnal temperature range is, too.
Thirdly, this is just one study by one group. As it notes, four previous studies reported significant decreases in the diurnal temperature range.
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JasonB at 10:13 AM on 3 July 2013Media Overlooking 90% of Global Warming
netprophet,
As KR mentioned, space for solar isn't a problem. Using an existing parabolic trough system like Nevada Solar One as a benchmark (134 GWh/year, 1.6km2) you could generate the entire planet’s current annual energy consumption (not just electricity) using just 17% of the Sahara desert.
Consider also the fact that we have already disturbed, by coal mining, an area (~8.4 million acres in the US alone) equal to that required to provide all power using solar thermal, and that coal mining has a much bigger impact on the area affected than simply putting it in the shade, and that coal also usually happens to be located in much higher-value areas than solar thermal plants would be.
Solar PV is even less of an issue, because it can sit on existing rooftops, and it has the advantage that it's competing with the end-user retail price of electricity.
If you're worried about cost, however, then you should be comparing to wind, rather than solar. Wind is now cheaper than new coal, which is why it's had such a dominant position in terms of new installed capacity for a while now. (Going forward, you can see the EIA's current estimates for 2018 here. Note that those figures are excluding "targeted tax credits such as the production or investment tax credit available for some technologies".) Wind can also co-exist with other uses of the land (most wind farms I've seen have been on working farms running sheep and cattle).
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KR at 09:32 AM on 3 July 20134 Hiroshima bombs worth of heat per second
arncliffe - "...a paper published last year by the team at BEST showed that the gap between night and day temperatures has actually been increasing for some twenty five years."
That's not what the data shows - Vose et al 2005; "Minimum temperature increased about twice as fast as maximum temperature over global land areas since 1950, resulting in a broad decline in the diurnal temperature range...", and Zhou et al 2009; "Observations show that the surface diurnal temperature range (DTR) has decreased since 1950s over most global land areas..." would disagree.
If you have a reference, it would be interesting to look at - but your assertion is contrary to the data I know of.
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Manwichstick at 07:10 AM on 3 July 20134 Hiroshima bombs worth of heat per second
@arncliffe
I would be very skeptical of the claim:
the team at BEST showed that the gap between night and day temperatures has actually been increasing for some twenty five years.
Not in my country, Canada. Winters are warming faster than summers and daytime minimums are increasing faster than daytime maximums. Just as predicted.
And BTW, if someone provides you with data, or explictly argues, that the sun is magically, or increasing some sort of output that is the cause of the earth's additional heat accumulation... they are instantly not a trustworthy source.
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KR at 06:13 AM on 3 July 2013Media Overlooking 90% of Global Warming
netprophet - I don't believe either cost or area is a serious concern. I would suggest looking at one of the Renewable Baseload Energy threads, where this has been discussed in detail.
Space is simply not a problem - here are some maps indicating required generation area for solar or for wind:
[Source]
As to cost, Apple hasn't released figures, but it's estimated to be similar to the cost of its other data centers - all of which are powered from renewable energy sources, and none of which has bankrupted the quite profitable company.
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Dumb Scientist at 05:14 AM on 3 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
I set "custom" parameters equal to mine (with my 7th order human influence, etc.) but with Dr. Tung's noise parameters, and 10,000 runs seemed to show that the sensitivity to smoothing was similar to simulations using Dr. Tung's overall parameters. This would have suggested that my simulation's sensitivity to smoothing the AMO index was related to the relative noise levels. However, running 100,000 simulations of the custom parameters reveals sensitivity similar to my overall parameters, so my hypothesis was wrong.
I still don't know why my simulation is more sensitive to smoothing, but I think the important point is still that my parameters produce more realistic timeseries, correlations, variances, and error bars. (Also, attribution is still really a thermodynamics problem.)
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Rob Painting at 05:03 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Arncliffe - 1.My post on the cool-skin layer of the ocean hyper-links to 3 different papers on the topic, and those three papers cites numerous others in support of the physics, math, and observations involved. Climate science contrarians on the other hand cite none. Why do you think that is?
2. The simple experiment carried out by Professor Minnett whilst aboard the New Zealand research vessel Tangaroa (Maori for the god of the sea) is rather compelling. Why else would the surface waters warm under cloudy conditions? The typical contrarian response of furious handwaving is not an explanation.
3. The amount of sunlight reaching Earth has declined over the last 3 decades due to a decline in the sun's radiation output. Instead of a decline in ocean heat content, we have seen a dramatic increase - as the greenhouse gas-forcing of the ocean's cool-skin layer predicts.
4. Attempts to blame current ocean warming on natural factors are generally by people who have little understanding of oceanography - such as the contrarian Bob Tisdale, and whose ideas are contradicted by the observations.
5. For example, mainstream science not only correctly predicted the current ocean warming, but accounts all previous Earth warming episodes that involved increased atmospheric concentrations of greenhouse gases - due to the fact that over 90% of heat goes into the oceans. The clearest illustration of this is the correlation between global temperature and atmospheric carbon dioxide (the main greenhouse gas) as shown in the ice core records dating back 800,000 years. The last 400,000 years of which is shown below:
How does Bob Tisdale's idea fare when you run it backward in time?
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arncliffe at 04:49 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Glenn Tamblyn
Sorry, another error: para 5 - Four Hiroshima bombs PER SECOND
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netprophet at 04:42 AM on 3 July 2013Media Overlooking 90% of Global Warming
Okay, let's assume we must act now as the President expects all Americans to do. Apple announced today it is putting a 43,500 kwhr (~20 MW unit) generating solar plant in Reno, NV. It is equivalent to the carbon generation of some 17,000+ homes. The capital cost will be ~ $75M based on costs of similar sized plants. In order to replace coal, which generates 1,517,000,000,000 kwhr, with solar, we would need some 35,000 such Apple size plants if the entire US had the sunlight of NV which it doesn't. Adjusting for many cloudy regions, we would need more like 70,000 such plants. The total investement would be over $5.0 trillion and in many regions there simply isn't enough space to put solar panels. How would we fund this?
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shoyemore at 02:52 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Taking Tom Curtis' point about etnropy, the energy accumulating in the atmosphere was once of high entropy, when it began in the sun's thermonuclear furnace. So the proviso around the "4 Hiroshima bombs" can be posed as "If we express this energy in units appropriate to where it began .... ", relateable to the sun's arriving energy on earth.
It still carries the image of a lorra, lorra energy, which is why I like it. And people can express it in more than one way .... "Here are different ways you can express this energy .. 4 Hiroshima bombs per second, or illuminating 71 billion Wembley sized areas with thirty five 100 Watt bulbs .... "
Obviously, no one should use the unit if they feel uncomfortable with its accompanying imagery, but a concrete example that you can explain is very usful.
Stephen Schneider: Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both.
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arncliffe at 02:50 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Glenn Tamblyn
Whoops Typo: 4th para - winds that move this mass of upwelling waterWESTWARD
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arncliffe at 02:45 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Glenn Tamblyn @22
Thank you for the time and trouble taken in your three responses. They were both informative and thought provoking.
I have two points that I think are worth making on your very clear 'walk through' of the likely role of CO2 in increased OHC.
Firstly, a paper published last year by the team at BEST showed that the gap between night and day temperatures has actually been increasing for some twenty five years. I don't have the reference to give you, nor the skills to provide a link if I did, but no doubt it is easily traceable.
The second point is the possibilty of solar radiation contributing to increased OHC. There seems to be general agreement across the Climate Science Blogosphere that when ENSO is in a 'La Nina', or 'neutral' phase the eastern equatorial pacific ocean and land regions cool due to easterly winds driving surface water westwards and generating an upwelling of cold water in the east. I understamd that the winds that move this mass of upwelling water eastward also create minimal cloud cover, thus exposing the water to high levels of solation on its long journey across the Pacific - over a third of the way around the globe. When this heated water reaches the western extremity of the Pacific, some moves through to the Indian Ocean, some diverts towards the poles, some remains in a pool to fuel the next El Nino and some goes down. As 'neutral' or 'La Nina phases have been dominant this century it seems credible to assume that this process has been a net contributor to OHC.
If I understand 'Shoyemore' @4 above correctly, the earth receives 1,900 Hiroshima bombs worth of solation per second (Elsewhere I have seen a figure of 1,000). As the process described above is occurring at the equator, a gain in OHC of 4 hiroshima bombs from solation alone doesn't seen too far fetched? - but I'm sure somone cleverer than me can do some sums to see just what the figure could be.
Turning to the question of the thin, cool- skin hypothesis: I agree that if it is flawed it may well be a question of swings and roundabouts as far as OHC is concerned. However, as the mechanisms by which CO2 affects OHC are so completely different in each case, I find it surprising that this issue can even be questioned at this stage (When so much effort and money has been expended on climate science over the last twenty or so years) and in re-reading Rob's article on the layer he references only one paper on the subject.
And so finally to the Roy Spencer paper that I mentioned. I am amazed to read that trends generated by the three bodies processing the same satellite temperature data vary by a factor of three. Someone ought to get them round a table!
Apologies for such a long winded post, but I felt that I owed you the best response that a layman can provide.
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Richard Lawson at 02:16 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Some of the heat goes into the melting of Arctic Ice. If we apply gentle heat to a beaker of water containing a lump of ice, the water temperature will not increase until the ice has finished melting.
So how much ice has melted?
The figure here:
http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/
shows that the September mean volume for 1979-2012 stands at 12,000 cubic km of ice.
The September value for 2012 stands at 3,000 cubic km of ice.
Therefore we have lost 8,000 cubic km of ice, since about 1997.1 cubic kilometer of ice = 10^15 grammes of ice
80 calories of heat are required to melt 1 gramme of ice.
Therefore to melt 1 cubic km of ice we need 8 * 10^16 calories
To melt 8000 cubic km ice we need 6.4 * 10 ^ 20 caloriesThat is 2.7 * 10^21 Joules which have gone into melting the Arctic ice since 1997.
This is clearly a lot of heat, but I have no idea how significant it is compared to the earth's energy budget.
It is 2*10^8 Hiroshima bombs, but how much surface warming would it represent, if, instead of going into melting ice, it went directly into heating the surface air?
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danielbacon at 02:16 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Very eloquent!
IMHO: The rate should be more important. You should say that by 1998. We were at a rate of ~2 Hiroshima bomb detonations per second and since that so called pause we have move to 4 Hiroshima bomb detonations per second. Or put it in step with time. Like in 198x we were at 1 by 199x at 2... and today at 4. How much many more Hiroshima bomb detonations does it need to increase before we start taking this seriously.
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johncl at 01:44 AM on 3 July 20134 Hiroshima bombs worth of heat per second
I do believe that many of us convinced in the seriousness of AGW really is trying to figure out how we can explain this to people so they are able to act upon it. Its really one of humanities biggest challenges, one that could have consequences on a planetary scale if not handled in time. Many believe we are really running of out of time. Talking about CO2 emission cuts of a certain % by 2050 isnt going to cut it. What is needed is for people to wake up and understand that our CO2 emissions through our addiction to fossil fuel burning is really turning up the thermostat of the planet causing a shift that the planet likely only have experienced in rather more cataclysmic events like the big siberian traps vulcanism or asteroide impact. The data shows a dramatic concentration of CO2 in both the air and seas at rates 10x past extinction events. I think its really cause for concern even though we dont really see the big consequences right this second. A tipping point can be passed (and most likely several have been passed now with the Arctic melting fast) where the changes happen so fast that global average temperatures could rise rapidly.
I do believe there is enough evidence now that the planet is absorbing more of the suns energy than it has in the past, and that this amount is significant even on a planetary scale (some are trying to make the 4 abombs per second sound like a small number, just like CO2 is only a small part of the atmosphere - this is a dangerous way of thinking - it only takes 0.25g of arsenic to kill a person). Looking at the broad picture, its really fantastic that life even exists on the planet, and while humans might feel like small gods wielding the power of fossil fuels, we really are quite insignificant and vulnurable, like all living things on this planet. I do believe we should treat our lucky position in this galaxy with some respect and at least acknowledge what we have discovered about simple physics. Sometimes one does not need proof in order to know something is right, if I fall out of a 10 story building, I will likely die - but I dont really need to watch someone fall to their death to understand this is a physical fact. The same way we do know CO2 is a greenhouse gas and that it traps heat. Glenn Tamblyn's line of reasoning perfectly explains a valid reason for the extra heat stored and I my opinion it shouldnt be hard for people to grasp this if they are willing to listen.
Cheers
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Eclectikus at 01:10 AM on 3 July 20134 Hiroshima bombs worth of heat per second
Hi all
I do not understand this obsession here with "science communicating". Science is not communicated (not as political propaganda), is disseminated and/or popularized, and as far as possible, when it has already passed the rigors of scientific method (empirical validation at least).
Glenn Tamblyn #24 says "It is a couple of decades too soon to claim that the models are wrong." Yep, However it is not too early to say that the models are correct... I think this is a version of scientific validation quite asymmetric, being naive.
Last but not less important. Using Hiroshima bomb (more than one hundred thousand dead), gives people an idea of the ethical level, and of the balance between popularize (or explaining) on the one hand, and convince (terrify rather), on this side of debate. From my point of view is a wrong strategy, to the point that it can only work with the more illiterate society. But hey, I'm aware that my opinion is worthless here. It's your choice.
Sincerely.
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John Mason at 00:33 AM on 3 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
LOL I missed that one when I corrected the others. It was around 0600 this morning when I did the other ones and I hadn't had enough coffee at the time! Sorted now :)
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Slioch at 00:06 AM on 3 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Another minor typo:
CaSiO3- (ie showing an overall -1 charge) in equation in top illustration should be simply CaSiO3 (ie with no charge).
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DSL at 23:33 PM on 2 July 2013It's El Niño
Li et al. 2013 might be a good basis for an intermediate article here:
"Predicting how the El Niño/Southern Oscillation (ENSO) will change with global warming is of enormous importance to society. ENSO exhibits considerable natural variability at interdecadal–centennial timescales5. Instrumental records are too short to determine whether ENSO has changed6 and existing reconstructions are often developed without adequate tropical records. Here we present a seven-century-long ENSO reconstruction based on 2,222 tree-ring chronologies from both the tropics and mid-latitudes in both hemispheres. The inclusion of tropical records enables us to achieve unprecedented accuracy, as attested by high correlations with equatorial Pacific coral and coherent modulation of global teleconnections that are consistent with an independent Northern Hemisphere temperature reconstruction. Our data indicate that ENSO activity in the late twentieth century was anomalously high over the past seven centuries, suggestive of a response to continuing global warming. Climate models disagree on the ENSO response to global warming, suggesting that many models underestimate the sensitivity to radiative perturbations. Illustrating the radiative effect, our reconstruction reveals a robust ENSO response to large tropical eruptions, with anomalous cooling in the east-central tropical Pacific in the year of eruption, followed by anomalous warming one year after. Our observations provide crucial constraints for improving climate models and their future projections." -
Glenn Tamblyn at 23:27 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
chriskoz
Yeah. This post touches on that, what happened during the Ordovician/Silurian mass extinction.
The Earth has a basic thermostat. But under the right circumstances it can go haywire. A mass extinction was the result.
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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!
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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.
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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."
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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.
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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.
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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.
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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.
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Cornelius Breadbasket at 20:34 PM on 2 July 20134 Hiroshima bombs worth of heat per second
EvilDoctorDaddy @ 20
LIKE :)
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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...
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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.
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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!
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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.
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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/>
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John Mason at 15:46 PM on 2 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Done :)
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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!
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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.
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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.
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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 +).
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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.
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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.
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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.
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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.
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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.
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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?
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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.
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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.
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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.
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