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Tom Dayton at 07:26 AM on 31 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Matzdj, understandably you might misunderstand what a "hindcast" is. It is produced in the same way as a forecast: The model is started very long ago--far earlier than the first year you are trying to hindcast. The model results gyrate wildly for a while as the simulated years tick by, then settle down. Eventually the model gets around to the first year you are trying to hindcast. The model continues through the years until getting to the year in which the model is being run. As the model continues spitting out results year by year in exactly the same process it has been following since it was started up, the "hindcasts" become "forecasts" only because the years that the models are simulating switch from being earlier than this year to being in the future from this year. For example, if climatologists start running their model on their computer in the year 1998 (I'm guessing that's where the vertical green dashed line in Figure 2 falls), then the model's outputs for each of the simulated years 1960 through 1997 are labeled "hindcasts" and the outputs for the simulated years 1998 and later are labeled "forecasts." Other than that labeling, there are no differences in how the model outputs are produced or reported. There are no adjustments to the model to tune it to actual climate.
What is done on the basis of analyses of model versus past reality is, as Kevin C explained, "improvement" of the fundamental physics of the model. I put "improvement" in quotes, because the modelers try to improve the physics but do not always succeed. They base any such adjustments on fundamental physical evidence, not by simply reducing the influence of an effect because they think it will make the projections better match observations. For example, if the modelers change the modeled reflectivity of clouds, they do so based on empirical and theoretical evidence specifically about cloud reflectivity, rather than simply making clouds more reflective because the model overall showed more heating than happened in reality. The reason that Kevin C wrote that sometimes those adjustments help the overall model output's fit and sometimes they don't, is precisely because those adjustments are not merely tunings to force the model to fit the past-observed reality.
Even if the modelers do succeed in improving the model's realism in some particular, narrow way, the effect on the model's overall, ultimate projection of temperature might be worse. For example, suppose cloud reflectivity had been modeled as too low, but that incorrect bias toward too much warming was counteracting a bias toward too much cooling in the modeling of volcanic aerosols. If the modelers genuinely improve the modeling of cloud reflectivity but do not realize the too-cool bias in the modeling of volcanic aerosols, then by reducing the warming from clouds they reduce its counterbalance of the overcooling from volcanoes, and the model's overall projection of temperature from all factors becomes worse in the too-cool direction.
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Andy Skuce at 07:26 AM on 31 March 2014Honey, I mitigated climate change
Ranyl provided a link to a site from a Hawaiian power company that has an interesting and somewhat depressing table. About 88% of the electricity on the islands is generated by fossil fuels, mostly diesel, which is a very expensive way to generate electricity. Yet, only 0.1% of the electricity is solar-generated. You would think that with reports that say that PV electricity is becoming as cheap as coal or gas fired electricity in the continental US and Germany, solar electricity in sunny Hawaii, where it displaces expensive diesel electricity, would be a no-brainer. Hawaiian residential electricity prices are $0.37 kW/hr, right up there with the more expensive European prices and three times what they are in the rest of the USA. Why hasn't there been a massive rush to install PV in Hawaii?
These issues are usually more complex than they appear from a quick Googling, so if anybody has any insights into this, I would like to hear them.
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Andy Skuce at 07:08 AM on 31 March 2014Honey, I mitigated climate change
Ari commented in his piece that natural gas replacing coal increases warming in the short ter because of the reduction in aerosols from coal. This observation applies equally to renewables that replace coal, as well. Particulates are a huge health risk, indoors and out, killing millions every year. They will surely be, or should be, reduced regardless of any short-term effect they have on the climate. And coal is not the only villain: the OECD reckons that there are 40,000 deaths per year in France from diesel fumes alone. It's not quite fair to link the climate effects of particulate emissions reductions with natural gas usage.
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Tom Dayton at 05:55 AM on 31 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Matzdj, you wrote "Do any of the models actually fit the data or are we just saying that if we look at all the models their dispersion sort of covers a range wide enough that the real data fall within?"
Your question is ill-formed, because you have not specified what "actually" means. No prediction in any branch of science ever is perfect; it is valid (accurate and precise--those terms mean different things) only to some degree. Deciding whether a prediction ("projection" in our case) is sufficiently valid depends on combined probabilities and consequences of the various types of correct and incorrect actions that you could take based on your interpretation of the sufficiency of the prediction/projection.
In this case we are concerned with the projections over periods of 30 years or more (the definition of "climate"). We know that projections over shorter periods are going to be poor, especially when you get down to periods as short as ten years. But we also know that the range of those short-term projections is bound by physics ("boundary conditions"), thereby demarcating the most probable longer term (climate) range of short-term projections. Those squiggly thin orange lines in Figure 2 above are individual runs of models. The models differ from each other by design, most having been built by different people. Usually each model also is run multiple times, varying some factors as a way of sampling the range of their possible behaviors since we are confident only in a particular range of those behaviors. It's similar to running an experiment multiple times to prevent being misled by one particular random set of circumstances. The high and low extents of those squiggly orange lines represent a reasonable estimate of the bounds of the temperature.
Perhaps you are being misled by a belief that if we cannot predict short term temperature we cannot predict long term temperature. That is a common but incorrect belief. See the post "The Difference Between Weather and Climate," and Steve Easterbrook's balloon analogy on his Serendipity site.
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Climate Models Show Remarkable Agreement with Recent Surface Warming
Matzdj - Climate models predict what the climate will do over the long haul given a particular set of forcings.
Climate models do not predict economic activity (or the GHGs and industrial aerosols produced), they do not predict volcanic eruptions, they do not predict the strength of the solar cycle, and while many of them include ENSO-like variations, they do not predict _when_ those El Nino or La Nina conditions will actually occur.
Various projections (what-if scenarios) have been run for the IPCC reports with reasonable estimates of those forcings variations, but it is entirely noteworthy that the CMIP3 and CMIP5 runs did not include the _particular_ set of variations over the last few years as actually occurred - that would have required precognition. And as per the opening post, when those _actual_ variations are taken into account rather than the before-hand projections, the climate models do indeed give a good reproduction of real climate behavior.
Which means that those models continue to be reasonably accurate representations of the Earths climate, and have not been invalidated in any way whatsoever.
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Tom Dayton at 02:46 AM on 31 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Matzdj, climate models are not intended for predicting the forcings (greenhouse gas emissions volcanic emissions, solar energy hitting the Earth, etc.), nor does anyone use them for that. Instead, climate models are intended for, and used for, "predicting" the climate response to one particular "scenario" of forcings. I put "predicting" in quotes, because the model run is not a genuine claim that that climate will come to pass, because there is no claim that that scenario of forcings will come to pass. Instead, the term "projecting" often is used instead of "predicting," to indicate that that climate is predicted to come to pass only if that particular scenario of forcings comes to pass. Those scenarios of forcings are the model "inputs" that other commenters have mentioned in their replies to you.
For each scenario of forcings that someone thinks might come to pass, that person can use those forcings as inputs to climate models to predict the resulting climate. To cover a range of possible scenarios, people run the climate models for each scenario to see the resulting range of possible climates. You can see that, for example, in Figure 4 in the post about Hansen's projections from 1981. You can also see it in the post about Hansen's projections from 1988. To learn about the forcings scenarios being used in the most recent IPCC reports, see the three-post series on the AR5 Representative Concentration Pathways.
To judge how well the climate models predict climate, we must input to those models the actual forcings for a given time period, so that we can then compare the models' predictions to the climate that actually happened in the real world where those particular forcings actually came to pass. That is the topic of the original post at the top of this whole comment stream.
To judge whether climate models will predict the climate in the future whose forcings we do not yet know, we must guess at what the forcing will be. We do that for a range of forcing scenarios. The bottom line is that every single remotely probable scenario of forcings yields predictions of dangerous warming.
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Honey, I mitigated climate change
CBDunkerson - Actually, space based dynamic generation (mirrors, boilers, and generators) has something of a mass advantage over PV, as the mirrors could be exceedingly light mylar or similar materials. It's been less frequently proposed mostly due to the need for maintaining moving parts - you can't just jump in a utility van and apply the wrench. Space based PV might benefit in mass from concentrator mirrors too, depending on whether any need for increased radiator mass would outweigh the reduction in panels.
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CBDunkerson at 02:14 AM on 31 March 2014Honey, I mitigated climate change
Michael Whittemore, either mirrors or PV panels could be directed to multiple ground based sites... though it would be much easier with PV panels because only the microwave emitter would need to be re-aligned rather than all of the mirrors. Also note that mirrors would effectively be creating a giant 'heat ray' from space focused on a small point on the ground, which could be a problem for birds and aircraft. Meanwhile, PV could be transmitted down harmlessly as microwaves over a wider area. Finally, the atmosphere (and clouds) block sunlight much more effectively than they do microwaves... so solar PV panels in space would actually produce more electricity than the same panels on the surface. The mirror approach could gain similar benefits by putting the steam turbines in orbit too, but getting that amount of mass (not to mention the water) into space would be prohibitively expensive.
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Kevin C at 01:07 AM on 31 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
But that's the wrong uncertainty. The uncertainty in the trend arises from the derivation of the temperature series from linearity. The uncertainty we need for that comparison is the uncertainty due to internal variability, which will generally be larger because it also includes differences in trend. There is also doubt as to whether model spread is a good measure of this.
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Honey, I mitigated climate change
Michael Whittemore - I believe that most space-based solar power proposals include using laser or microwave wireless power transmission to Earth; extension cords are sadly not practical with todays technology :) Power density would be considerably higher, given the lack of atmosphere, clouds, or night.
I suspect that using satellites as mirror concentrators would be less cost effective than just larger collection areas on the surface.
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Klapper at 00:03 AM on 31 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
@scaddenp #19:
"The models are good at predicting what 30 year trends will be however."
The current HadCRUT4 SAT trend for the last 30 years is 0.17C/decade +/- .05. The CMIP5 ensemble SAT trend for the same period (1984 to 2013 inclusive) is 0.26C/decade, which is outside the 2 sigma range of the empirical data. I checked the CMIP5 ensemble for both 80 to -90 and 90 to -90 (pole to pole) to see if the leaving the very high arctic out would improve, but it makes essentially no difference (0.26 compared to 0.25).
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Michael Whittemore at 23:34 PM on 30 March 2014Honey, I mitigated climate change
CBDunkerson my understanding is that it would take a large amount of panels to be put in space to generate enough energy but with mirrors they could focus on different power plants around the world and not just solar but the land based mirror ones too that generate steam.
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Honey, I mitigated climate change
Ranyl - PV, like any piece of electronics, does have manufacturing waste which must be managed, appropriately recycled, etc. As in the electronics industry, proper monitoring and regulation is necessary. As to coal - damage to watersheds and water supplies, the CO2 and greenhouse effects thereof that are at the center of the climate change discussion, and the particulate and even radioactive release of radon and other elements (with emissions being a continuous output, not just a one time manufacturing cost).
_All_ energy sources, coal, solar, nuclear, etc, have side effects - it's a matter of deciding which effects are more problematic. I would strongly argue in the comparison of solar and coal that the advantages of no carbon emissions _hugely_ gives the balance to solar, and I consider your solar objections more quibbling than anything else.
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michael sweet at 21:47 PM on 30 March 2014Honey, I mitigated climate change
Ranyl,
I quoted from your sources to show that solar did not have the problems you claimed. You respond with more unsupported wild claims You have provided exactly zero quotes to support your wild claims. Your assertions about solar are false. Your claim that Hawaii uses extensive geothermal must be supported by a cite. I have seen extensive data supporting the claim that Hawaii has reduced its fossil fuel use with solar. What do you thnk happens to fossiil fuel use when wind generates more energy? Do consumers use more power? Be serious, of course fossil fuel use goes down. You appear to claim that all energy use must be curtailed. That will never happen. You must provide an alternate scenerio for people to live.
You are ranting and sloganeering. Provide more citations that support your wild claims and less assertions from ignorance.
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ranyl at 21:17 PM on 30 March 2014Honey, I mitigated climate change
"Ranyl, you may want to take a look at Hawaii. It has greatly decreased fossil fuel usage by adopting renewable power. Your belief that this is impossible is thus simply wrong."
Who said this was a beleif, and I'm not Richard York, he is and he worked out, he didn't just beleive it.
And Hawaii has extensive Geothermal which York isn't discussing, he is discussing PV, wind etc...and of relevance to this article and future food as climate change puts the strain on, "In May we signed a power purchase agreement with Hu Honua Bioenergy for up to 21.5 MW of firm renewable energy fueled by locally grown and produced biomass on the Big Island. Pending Public Utilities Commission approval, plans call for bringing the power plant online by the end of 2013", that is lot of MW to grow., are people actually starving in our world why we grow plants to serve of power addiction, is that really happening??? and advocated by environmentalists?
And I see all good now because toxic PV is cheap and easy to do I see, no ownder I passed a several acrePV array in yesterday on prime farmland, wonder that does to soil carbon, the ecosystem in the soil and dispalced food crop?How much land would be needed to supply a major city and industry from PV and what storage would be needed, or are talking a global power sharing grid?
Any environmental impacts of common storage devices? Batteries Lithium mining, trasnport, toxic prodcution, toxic waste, etc,etc, what biodiverstiy crisis?
And the grid any additionals needed to that to cope with PV?
Is the answer to actual admit that there si no clean power production, that we already need to remove ~100ppm from the atmosphere to get ot 350ppm (the 50% of emissions stored in the sinks will be released as the atmospheric CO2 conc falls accordign thse guys;
Atmospheric carbon dioxide removal: long-term consequences and commitment, Long Cao and Ken Caldeira, Environ. Res. Lett. 5 (2010)
And these guys estimate if we stopped all CO2 tomorrow only drops very slowy at best 0.2ppm/y-1, so take the earth 250years to get 350ppm without the re-release from the sinks.How difficult is it to recover from dangerous levels of global warming? J A Lowe1, C Huntingford2, S C B Raper3, C D Jones4, S K Liddicoat4 and L K Gohar1, Environ. Res. Lett. 4 (2009)
When CO2 was 350ppm last the wordl was 3-5C hotter and 20-25m sea level rise different and the cliamtic zones and oceanic zones where quite different, and severe weather in terms of rain amounts and wind dissipation must have been quite something with all that extra heat and energy about.We are admidst a rapid mass extinction, very rapid loss of biodiversity and all due to human practices of consumption, overexploitation, fertilization, land use change and introducign am array of toxic substances.
And here we are discussing using an technology with a very high energy input to produce, multiple toxic waste issues at all stages including recycling, that is totally dependent on fossil fuels to make at presetnt and user of land now in more and more places.
And now it si becoming cheap and open to mass manufacture and can be put into anything so now totally open to mass ocerexploitation so its all ok.
Therefore coal is awful and if we continue with that then the upshot civilization chaos and that is never pretty.
Solar PV is another enrgy source, that isn't as bad, but pretty awful and if waste leaks or factory blown up very bad as substances used in manufacture so toxic and GHG effects so high, imagine if all the NF3 escaped.
Therefore the question here is to either power down or use PV and continue the harm and probaly increase it as the full extent of putting waste into the environment emerges due to bioaccumulation and concentrations of these substances, and how carbon does it cost when you disrupt an ecosystem?
Choice Power down or toxic waste?
And lastly to get to 350ppm means we need to be carbonnegative and every ounce of carbon has to be recovered so where si all this carbon to make all these PV's coming from.
And as many LCA (lots very biased) give ~6-8years for PV, that measn for 1 year production you have make 6 to 8 years worth, which of course takes at present all number of PV's of fossil fuels to make an PV factory from PV alone, spo that is a lot, 36 to 64 years of equivalent emissions to set up, and that isn't including NF3 or Hydroflourides or the effects of the toxic wsaste on the environmental carbon fluxes.
Power down is safe, costs no GHG, produces no waste and is actually easy to do.
And yes I am writing on a CPU which is toxic waste, and yes we do need to do somethign about that to.
We are between a very hard rock and a very hard place, 35ppm is a miracle away, needs stoppign all fossil fuel use asap and not using other powwr generation that has large environmental imapcts especailly in big scale overexploitation. And we haven't even started on where the silicon coms from, the rare earths, the aluminium, the solder, the lead, the glass, the transportation, making the factories, all the chemical used, and so and so on...
Therefore the choice is powerdown nice and safe in all respects or not and keep on harming just not quite severely as coal?
Moderator Response:[RH] Hot-linked URL.
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CBDunkerson at 19:19 PM on 30 March 2014Honey, I mitigated climate change
Michael Whittemore, once you get to the point of launching things into orbit it actually makes more sense to put solar PV panels in space to collect sunlight 100% of the time and beam the power down to rectifying antennas on the surface.
That said, I think what I call 'solar overkill' may be the most likely / cost effective scenario. There are technologies in place which can gather solar PV energy from transparent windows, roofing shingles, building siding, sidewalks, driveways, and even clothing. If the cost of solar PV continues to plummet, we may see it being incorporated into anything and everything... resulting in most buildings generating more electricity than they use and thus always sufficient 'extra' power to transfer to sites which are currently dark.
Ranyl, you may want to take a look at Hawaii. It has greatly decreased fossil fuel usage by adopting renewable power. Your belief that this is impossible is thus simply wrong.
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ranyl at 18:44 PM on 30 March 2014Honey, I mitigated climate change
"If this is the best you can do the solar industry is ready to go all out. All large electronic firms in China should be carefully watched. Your claims that solar (and wind) cannot be environmentally produced do not stand up to a review of your own citations."
Firstly yes PV is better than coal, but we need to stop using coal asap as I said, no brainer just like the article say, but not sure why you use that as proof of PV being good for the environment, PV are just another power generation technology with major environmental impacts, like a machine gun we kill loads of people (coal) compared to a hand gun, a hand gun (PV) still kills.
Therefore nothing you have said is saying making PV's is of environmental benefit, we have hope they make clean factories, we have to hope, but how do they treat the waste and what do they do with it? How do they make in benign exactly?
LINK
Lots of waste left behind here from a clean factory.
https://alumni.stanford.edu/get/page/magazine/article/?article_id=30242
Another statement on some of the issues and again we hope factories will clean up...and how many factories are in China and growing
http://www.nrel.gov/docs/fy12osti/53938.pdf“Non-hydro renewable sources have a positive coefficient, indicating that renewables tend to simply be added to the energy mix without displacing fossil fuels.”
“The failure of non-fossil energy sources to displace fossil ones is probably in part attributable to the established energy system where there is a lock-in to using fossil fuels as the base energy source because of their long-standing prevalence and existing infrastructure and to the political and economic power of the fossil-fuel industry.”
Richard York1 Do alternative energy sources displace fossil fuels?
Nature Climate Change Volume: 2, Pages: 441–443, 2012They haven't even displaced any coal yet either, so all just additional harm.
PV is a dirty, high enery environmentally destrcutive technology, better than coal but still in no way an environmental benefit at all to no one or anything.
Moderator Response:[RH] Hot-linked URL.
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Kevin C at 18:26 PM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Matzdj asks an interesting question:
Can you tell me how many adjustable parameters there are in each of these models?
The question doesn't really apply, because climate models are not statistial models. However from the point of view of fitting global mean temperature, I think the most meaningful answer would be 1 - because we align the baselines to compare the models.
Climate models are optimised by improving the physics. In some cases the physics cannot be modelled at a sufficiently fine scale, and in these cases parameters are used. However those parameters are not, and cannot be, optimised to reproduce global mean temperature - they are optimised to produce the right local behaviour. The global impact of those optimisations is an emergent property, and may improve or degrade the fit.
Of course we then get into the tuning myth, which was explored in another recent discussion - from memory I think we found that it arose in part from not counting the number of independant models correctly, and has changed signs between CMIP3 and 5.
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scaddenp at 17:02 PM on 30 March 2014Global warming not slowing - it's speeding up
There may be another source of confusion - the OHC shown is change in OHC compared to 1955-2006 baseline period not the absolute OHC.
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scaddenp at 16:57 PM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Martin, model are not skillful at decadal level predictions. There is a very good reason why climate is defined as 30 year means. Besides ENSO and solar variation, there are modes of internal variability on decadal scales. The models are good at predicting what 30 year trends will be however. The AR5 report indicates the ensemble range. I would say the uncertainty band is at least as large as this. Emissions and aerosols are under our control so model can only deal with scenarios for these.
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scaddenp at 16:17 PM on 30 March 2014Global warming not slowing - it's speeding up
Sorry, you are saying T = 3/2 kT?? that doesnt make sense. The temperature change from a given no. of joules is divide by volume of water and volumetric heat capacity (4.15MJ/m3 approximately). OHC is actually calculated from the deltaT by same formula.
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Michael Whittemore at 15:10 PM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Matzdj read the post again. Models can't predict elninos/laninas, solar forcing or volcanic eruptions. No one can predict them. This post is just showing that when you take out these effects on the climate system, the models are spot on.
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Rob Painting at 15:07 PM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
The output of the climate models depend on the input. The CMIP5 climate models were fed input, a net climate forcing, that does not appear to have occurred. When fed the updated input, the multi-model mean and observed temperatures are well-matched.
None of this has anything to do with adjusting how the models themselves are run.
As for hindcasts, similar problems remain. What net forcing was the climate system itself actually responding to back then? Earlier periods are less well contrained by observations, so we can only make an educated best guess.
And one last thing, the thrust of your comment constitutes a breach of the comments policy namely; slogan-chanting and accusations of scientific malfeasance. Further breaches will likely attract moderation.
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BruceWilliams at 14:58 PM on 30 March 2014Does the global warming 'pause' mean what you think it means?
Tom Curtis @ 27
Although not directly coupled, would it be fair to say that the OHC must eventually follow the SST?
I ask because if not then the heat transfer characteristics surface to bottom must be different than from bottom to top, or there is a heat/cooling action going on at the bottom?
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BruceWilliams at 14:22 PM on 30 March 2014Global warming not slowing - it's speeding up
Concerning post #23 scaddenp at 08:25 AM on 14 March, 2014
According to the graph presented, the energy content of the southern hemisphere went from 4.5e22 J to 9e22 J in about 5 years. Since temperature is simply 3/2 kT would this not indicate that the temperature of the southern hemisphere ocean area has doubled in the last 5 years?
Note: k = Boltzman constant
T = Temperature (average)
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Matzdj10109 at 12:35 PM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Please help me understand. Do any of the models actually fit the data or are we just saying that if we look at all the models their dispersion sort of covers a range wide enough that the real data fall within?
Can you tell me how many adjustable parameters there are in each of these models? (-snip-).
I understand that at any given time, each model is fit to the historical data and the adjustable parameters are calculated. If it fits with a good correlation, that's great, but the test of the model is whether future data fits what the model predicts. It's not good science to take the future data, refit the adjustable parameters and then report that the model fits. That usually indicates that there probably is some important physical issue that is either not in the model or not being considered correctly - maybe something like cloud formation?
If you want to put a parameter into the model that does some cooling if a volcano explodes or a La Niña happens, that's ok, but only if you do it in a way that incorporates it without using the result to readjust the fit. (-snip-).
If someone can take just one model and show how it has predicted the 10 years after the parameters were fit, I would be very appreciative.
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Michael Whittemore at 11:18 AM on 30 March 2014Honey, I mitigated climate change
Regarding solar farms and molten salt farms, you would think governments would put mirrors in space to keep these powers plants working 24/7
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scaddenp at 10:51 AM on 30 March 20142014 SkS Weekly News Roundup #13A
"How certain" is actually what is relevant rather than philosphical arguments about what is knowable and what is not. Policy makers have to make decisions all the time in the face of uncertainty. It is possible that some new theory will explain all our observations what implying that we need to act on our emissions, but extremely unlikely. "The race is not always to the fastest, nor the fight to the strongest, - but that's the way to bet". Trying to use the lack of certainty as an excuse for inaction is extremely poor policy. Uncertainty cuts both ways.
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Tom Dayton at 10:41 AM on 30 March 20142014 SkS Weekly News Roundup #13A
Tom Curtis, not even mathematics is absolutely certain, because humans create the mathematical descriptions. Else all mathematical "proofs" would be unerringly correct forevermore, at the first moment that any one human was "certain" of their correctness.
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Tom Curtis at 09:51 AM on 30 March 20142014 SkS Weekly News Roundup #13A
Stephen Baines @16, thanks for a well written and clear exposition. It misses, however, some nuances. Specifically, and first, when we practice science as an endeavour, we continue to use the "certain" parts of science as an instrument (often literally) in our inquiry about the uncertain parts. If we use a microscope, we relly on the near absolute certainty of aspects of optics in doing so. If we examine the operation of climates, we relly on the certainty of the Navier-Stokes equations, of the laws of thermodynamics, Galilein mechcanics and Newtonian dynamics as approximations to their relativitistic counter parts at low velocities, the composition of the atmosphere, the radiative spectrums of the components of the atmosphere, the response to atmospheres to Newtonian gravity (as an approximation to their behaviour under General Relativity) and so on. We rely on the certainty of hundreds of physical laws in the instruments we use to probe the climate and its components.
Further, of necessity we always focus our enquiries such that what is uncertain is a small part of the operation, and what is certain is large. So far as is possible, we always make sure there is only one, or very few dependant variables. Where we not to do so, no enquiry could reduce confusion. Consequently, even as an endeavour, that which is certain in science far exceeds that which is uncertain.
What is true, almost tautologically, is that which is subject to active enquiry is not yet certain. Science always enquires on the edge of ignorance; from which we cannot conclude that 'nearly all of science is ignorance'.
The second point is that no part of science (except mathematics) is absolutely certain. Even the theory that there is an external world (ie, that we are not "brains in vats") could, in principle be overthrown by continuing observation. But the possibility of this, or that the Earth is flat, or (and here with space I would list the majority of scientific knowledge), is so small that without the occurence of evidence that calls it into question, the possibility of error on these points can be neglected in practise.
There is an unfortunate tendency among some scientists and commetators on science to notice the first poin in the above paragraph, and to think that it seriously calls into question the second. Of course, no scientist actually puts that radical skepticism into practise. If they were to do so, they would never determine any result, out of complete mistrust of their instruments.
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martin3818 at 08:53 AM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Knowing quantitavely what we do now about the different forcings how good are predictions or projections regarding global surface temperatures for the next 10 years?
I'm sure that volcanoes and ENSO still can't be predicted. But what about solar and aerosols. How broad should the uncertainty band around the ensemble mean be for the year 2024?
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Kevin C at 07:21 AM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
The thermal inertia of the climate system means that the temperature takes time to respond to a change in forcing. In the case of the solar forcing, the temperature response is expected to lag the forcing by 30-50 degrees, or 11-18 months. So even if we have just passed the peak of the solar cycle, the peak effect on temperatures may not occur for another year. (And of course solar cycles are rather variable in length.)
See for example:
- White WB, Lean J, Cayan DR, Dettinger MD (1997) Response of global upper ocean temperature to changing solar irradiance. J Geophys Res 102:3255-3266.
- Van Hateren, J. H. (2013). A fractal climate response function can simulate global average temperature trends of the modern era and the past millennium. Climate Dynamics, 40(11-12), 2651-2670.
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NewYorkJ at 07:18 AM on 30 March 2014Cherry picked and misrepresented climate science undermines FiveThirtyEight brand
Like gentlemen?
Seriously?
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Klapper at 06:36 AM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
@jja #9:
"...and the current solar cycle also reaches a maximum of intensity during the years 2015-2016"
That is highly unlikely since the official start of solar cycle 24 is Jan 2008. A 2016 peak would put the cycle 24 peak at least 7 years after the start of the cycle, which is highly implausible.
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Klapper at 06:31 AM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
@tonydunc #5:
"Klapper, what makes you say Sea level rise is realtivel noise free?"
Do a rolling R-squared using a 10 year period on the sea level data (satellite or tide guage) and compare it to the same metric on any atmospheric data set (also a 10 year period). A crude comparison but the results show sea level have much lower deviation than other climate metrics.
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PhilBMorris at 06:17 AM on 30 March 2014Honey, I mitigated climate change
We have to stay below 450 ppm CO2 (even that may be too high), a level we'll reach by 2033 with the BAU approach, and then get down to 350 ppm ASAP. US EIA predicts global electricty production by 2025 as 4.1 million MW installed capacity from fossil fuels. That is equivalent to 6300 London Arrays, currently the largest offshore wind farm. Until there are appropriate advances in battery storage systems, wind power will never achieve base load capabilities. The US EIA also estimates that electricty production and direct heating produce just 31% of all CO2 emmisions; the only other sector that has the potential for replacing fossil fuels is transportation (another 20%) but that requires an entirely new infrastructure for electric vehicles and/or hydrogen fuel.
That still leaves about 50% of CO2 emmisions that are not readily dealt with (manufacturing, construction, land use/direct emissions etc) We'd have to squester atmospheric CO2in massive amounts, which, unless there's a breakthrough in technology, will require copious amounts of electricty - from non-fossil sources of course (see House et. al. Royal Society of Chemistry, 2008, Direct Air Capture of CO2 with Chemicals, American Physical Society, 2011, and Rau et. Al Institute of Marine Sciences, U. Of California, 2013).
Our only hope is nuclear, but not the uranium based systems that Rickover decided on in the 1970's but throium based systems that are walk away safe; produce far less radioactive byproducts of far lower toxicity; are far more prolieration resistant, and potentially far cheaper to build that the current PWR systems. Maybe fusion will finally get the breakthrough needed to produce power, but as a civilzation we cannot rely on hoped for solutions. Getting our political systems to really deal with climate change is in itself a problem we seem unable to overcome, let alone techical issues of implementing timely solutions. I for one have come to realise that adaptation, really feasible for a modest prcentage of the global population, is now inevitable. Mitigation becomes less and less likely as the years go by.
The book '2084: An Oral History of the Great Warming' by James Powell may well be prescient.
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scaddenp at 06:11 AM on 30 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
I would also point out that Argo data is not an input into models.
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Andy Skuce at 03:06 AM on 30 March 2014Cherry picked and misrepresented climate science undermines FiveThirtyEight brand
i recommend that people read the addendum to a recent RealClimate piece, where Stefan Rahmstorf shows how gentlemanly Pielke was in a discussion over the Russian heat wave paper.
Steve McIntyre also claims to be a gentleman over at Climate Audit, at least in a Wildean sense. Judith Curry also talks admiringly about the wave of "gentleman scientists" who doubt the seriousness of climate change.
There seems to be a lot of it about.
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Stephen Baines at 01:38 AM on 30 March 20142014 SkS Weekly News Roundup #13A
Poster,
"Science" can be interpreted as an endeavor, or as the body of scientific knowledge derived from that endeavor. The scientific endeavor focusses on unresolved issues, because there is no need to actively study resolved issues. It can be tautological, therefore, to say there is much uncertainty in the endeavor of science because uncertainty is specifically what the activity of science addresses - and this is what journals like Nature will highlight as they are concerned with cutting edge scientific endeavor.
At the same time, it is non-sense to suggest that issues that have been resolved are still uncertain. There is a huge body of scientifically resolved issues which we build on to further the scientific endeavor. Climate science is no different. There is no doubt that CO2 has increased substantially since the beginning of the industrial period, that human activity is responsible of that increase, that the greenhouse effect exists, and that warming of the planet has occured in response. Those issues have been resolved by decades, sometimes over a century, of prior scientific research.
Most of the current research now addresses how the warming will manifest itself going forward, the implications of that warming for us and the living world and the possible ways that feedbacks could exacerbate or ameliorate those implications. Of course there is uncertainty in those topics — they wouldn't be interesting to scientists otherwise! But that uncertainty has absolutely no bearing on the body of resolved scientific knowledge upon which that new research is built.
Your broad generalizations haphazardly paint over this distinction between the endeavor of science and the body of established scientific knowledge upon which it builds. In doing so, you make science generally sound like a fruitless enterprise that never generates established knowledge, which is non-sense given how much predictive ability science gives us in our everyday lives, including with respect to climate.
I do understand that someone from a different branch of science might be unclear about what exactly is the established science in climate science, and what are the new cutting edge research questions for scientific endeavor. Before expressing doubt, I would expect you to educate yourself about those, just as someone from a different discipline would expect me to educate myself about his/her field before making broad statements.
If you don't do that, regardless of your real intentions, you appear just like those who deliberately obfuscate because of their non-scientific agenda.
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Rob Painting at 19:21 PM on 29 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
"Some sources suggest that > 40% of Argo floats are either non- operational or produce questionable data"
Let me guess, these 'sources' don't happen to be oceanographers, but are instead non-experts ideologically resistant to the whole idea of climate-driven policy?
If readers are interested in the robustness of ocean heat measurements they should consider the IPCC AR5, Abraham et al (2013) & Von Schuckmann et al (2013). Yes the oceans are warming and the consequent thermal expansion of seawater is one of the main contributors to sea level rise.
IPCC AR5 Chapter 3 states:
"It is virtually certain that upper ocean (0 to 700 m) heat content increased during the relatively well-sampled 40-year period from 1971 to 2010"
&
"Warming of the ocean between 700 and 2000m likely contributed about 30% of the total increase in global ocean heat content (0 to 2000m) between 1957 and 2009. Although globally integrated ocean heat content in some of the 0 to 700m estimates increased more slowly from 2003 to 2010 than over the previous decade, ocean heat uptake from 700 to 2000 m likely continued unabated during this period."
As for the models, see figure 3 in the post. CMIP5 seems to do a reasonable job of simulating surface temperatures over the last hundred years. With better forcing estimates going back in time they might do an even better job. It's certainly plausible based on the work of Schmidt et al (2014).
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Tom Curtis at 18:54 PM on 29 March 20142014 SkS Weekly News Roundup #13A
Poster @12 forward, I remind you that your statement was that:
"...Mr Cook and his team might take note that there is very little certainty in science."
(My emphasis)
Your statement was about certainty in science in general, rather than the level of certainty of specific aspects of climate science. Pointing to specific aspects of climate science with a high level of uncertainty therefore represents a straigh forward bait and switch.
If you want to defend your absurd notion that "there is very little certainty in science", defend it. And start by showing that there is very little certainty that the Earth is an oblate speroid, rather than a euclidean plain. Alternatively, concede that you massively overstated the facts - to the point of absurdity- for rhetorical purposes. And let us have no more of this dishonest rhetorical game of pretending you were saying something entirely different to that which you actually said.
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Poster9662 at 18:42 PM on 29 March 20142014 SkS Weekly News Roundup #13A
My apologies for my sloppy typing, there are too many typographical errors in the above comment. I wrote"inter aloia containsd" that should be inter alia contains". That said the piece in Nature is well worth reading for itself as it illiustrates both uncertainties in climate science and the efforts being made to resolve them
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Poster9662 at 18:32 PM on 29 March 20142014 SkS Weekly News Roundup #13A
Tom Curtis re-reading your comments about certainty is science I encourage you to read this piece from Nature
http://www.nature.com/news/climate-change-the-case-of-the-missing-heat-1.14525
It commences "The biggest mystery in climate science today may have begun, unbeknownst to anybody at the time, with a subtle weakening of the tropical trade winds blowing across the Pacific Ocean in late 1997." and inter aloia containsd this "Climate scientists, meanwhile, know that heat must still be building up somewhere in the climate system, but they have struggled to explain where it is going, if not into the atmosphere. Some have begun to wonder whether there is something amiss in their models."
(-snip-)
Moderator Response:[DB] Inflammatory tone snipped.
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chriskoz at 18:29 PM on 29 March 2014Cherry picked and misrepresented climate science undermines FiveThirtyEight brand
Interesting turn on Pielke's critique. He responded by threatening his critics (he picked up Mike Mann & Kevin Trenberth - based on their prominence I guess) therefore ashaming himself. Up to the point that Nate Silver needed to appologise on his behalf.
IMO Pielke Jr has issues not just with his scientific integrity but also with his basic principles. His words:
"More generally, in the future how about we agree to disagree over scientific topics like gentlemen?"
actually apply to himself! True gentelmen never opine/argue with threatening language! They don't need to use threats to uphold their public image!
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jja at 15:42 PM on 29 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
If the 2015 El Nino projections are true and we experience a temperature spike similar to the 1997-1998 El Nino, and the current solar cycle also reaches a maximum of intensity during the years 2015-2016 and if China begins to more agressively scrub its SOx emissions then we may see a significant spike in warming on a global average over the next few years.
Recent shifts in the jetstream may be harbingers of larger shifts in the global hydrological flows. If this is the case then the added tropical atmospheric moisture associated with the El Nino flow may produce a stark shift in global weather patterns. -
Poster9662 at 15:39 PM on 29 March 20142014 SkS Weekly News Roundup #13A
Tom Curtis
I suggest you might read this, taking especial note of the section "From the Royal Society's archives. If you read it you might like to reflect on your "Utter Garbage" comment
http://royalsociety.org/further/uncertainty-in-science
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Andy Skuce at 11:03 AM on 29 March 2014The Carbon Bubble - Unburnable Fossil Fuels - Seminar and Discussion
chriskoz, I agree that developing geothermal energy would be a good use of oil company technical expertise and capital. And I agree that the most effective way to sequester carbon is to leave it in the ground.
But I don't think we can brush off CCS quite so easily, although I am very skeptical than it can be scaled up and deployed fast enough to make a big dent in emissions. However, many researchers, like the IEA and the people who did the socio-economic modelling behind the RCP2.6 scenario (the only one that keeps us below 2 degrees) foresee a big role for CCS.
This graph (modified Figure 2 from here) shows CCS (including biomass CCS) will be the source of about 40% of our energy supply by 2080. If that CCS business is captured by current fossil fuel firms, the total size of fossil fuel energy (CCS and non-CCS) will be about double the size that it is now. This scenario is hardly one in which the fossil fuel industry fades into extinction.
Now, you can be skeptical about this ever happening on this scale and on this timeline as I am, but CCS does have some respectable and thoughtful proponents.
There is a recent article on CCS in Wired by Charles Mann that is worth a read. He quotes Fatih Birol (IEA chief economist) as saying:
“I don’t know of any other technology which is so critical for the health of the planet and at the same time for which we have almost no appetite,”
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Riduna at 10:56 AM on 29 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
An interesting article on which I would make two observations: Firstly: the author points out that the accuracy of model output is dependent on reliable input – the GIGO factor. On this point one should perhaps question the reliability of Argo data. Just how reliable is it? Some sources suggest that > 40% of Argo floats are either non- operational or produce questionable data.Secondly: the author suggests that CMIP5 has been proven to be a reliable model when compared with observation – but is this really so? An improved model, maybe. (Overland et al (2014) questions the ability of CMIP5 to accurately show current or predict future temperature, particularly in higher latitudes. Predicting average global surface temperature, even in the short-term is, as the author points out, an extraordinarily difficult and complex process since it relies on the reliability and accuracy of a vast amount of data and models which predict the interaction of these data. Even though we do not have access to such data, two things can be predicted with reasonable certainty.1. El Nino is very likely to become established within the next 6-18 months and may well be as strong as or stronger than the one experienced in 1997/98.2. We shall not need complex models and data to appreciate its effect on average global surface temperature or the prognostications of so called “skeptics” who have rashly declared a hiatus in global warming, or its demise.Nor does one need sophisticated models to tell us that, as long as we continue to pump increasing amounts of greenhouse gases into the atmosphere, temperatures will continue rising, first with dangerous, then with catastrophic consequences. -
wili at 10:18 AM on 29 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Yes, tonyd, sea level can vary quite a bit and can be quite noisy. The same heat that warms and expands the ocean also lofts more water into the air and then onto land, where it can stay in some cases long enough to alter ocean levels. It may take a few years for the signal to become perfectly clear, but the latest measurements from Greenland and Antarctica show that we're in for accelerating sea level rise from here on out.
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Rob Painting at 08:44 AM on 29 March 2014Climate Models Show Remarkable Agreement with Recent Surface Warming
Probably the best estimate of ocean warming is Balmaseda et al (2013) because, amongst other things, it combines multiple datasets and feeds these into an ocean model - thus accounting for known physics. This provides a more robust estimate for sparse or missing data.
Here's the ocean heat content trend:
What you will notice is that there an abrupt spike in heat uptake in the early 2000's followed by a slower rate up toward the present. This trend is probably one of the most obvious features of the Hiroshima Widget too.
So even though the total uptake of heat into the Earth system is greater in the last 16 years than the previous 16 years, it has not steadily accelerated. It would, therefore, be illogical to expect sea level rise to exhibit ongoing acceleration when one of the main contributors (thermal expansion) hasn't. The Cazenave et al (2014) paper seems more in line with mainstream scientific expectations, although that isn't the final word either.
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