Arguments
Global Warming’s Missing Heat: Look Back In Anger (and considerable disbelief)…
Posted on 12 September 2013 by gpwayne
Probably the most frustrating argument on climate science in the public discourse is about the hiatus in surface temperature rise, and the failure of the models to predict it. The persistent hyperbole, the seeming logic validated largely by a disregard for some basic laws of physics, is merely a prelude to the frenzy that the next IPCC report (AR5) is likely to fuel. There are trying times ahead.
To better gird ourselves before the onslaught, it seems like a good time to review another important report, which speaks very clearly to the current arguments about the rate of global warming and the accuracy of the climate models. Here’s a taster from the foreword:
“If carbon dioxide continues to increase, the study group finds no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible. The conclusions of prior studies have been generally reaffirmed. However, the study group points out that the ocean, the great and ponderous flywheel of the global climate system, may be expected to slow the course of observable climatic change. A wait-and-see policy may mean waiting until it is too late”.
Sage words then. Anyway, delving into the detail, we find a clear statement about likely temperature increases for a doubling of CO2 - or climate sensitivity - based on global circulation models (GCMs):
"When it is assumed that the CO2 content of the atmosphere is doubled and statistical thermal equilibrium is achieved, the more realistic of the modeling efforts predict a global surface warming of between 2°C and 3.5°C, with greater increases at high latitudes".
And then we come to the part so relevant to topical argument:
“One of the major uncertainties has to do with the transfer of the increased heat into the oceans. It is well known that the oceans are a thermal regulator, warming the air in winter and cooling it in summer. The standard assumption has been that, while heat is transferred rapidly into a relatively thin, well- mixed surface layer of the ocean (averaging about 70 m in depth), the transfer into the deeper waters is so slow that the atmospheric temperature reaches effective equilibrium with the mixed layer in a decade or so…It seems to us quite possible that the capacity of the deeper oceans to absorb heat has been seriously underestimated, especially that of the intermediate waters of the subtropical gyres lying below the mixed layer and above the main thermocline. If this is so, warming will proceed at a slower rate until these intermediate waters are brought to a temperature at which they can no longer absorb heat.
“Our estimates of the rates of vertical exchange of mass between the mixed and intermediate layers and the volumes of water involved give a delay of the order of decades in the time at which thermal equilibrium will be reached. This delay implies that the actual warming at any given time will be appreciably less than that calculated on the assumption that thermal equilibrium is reached quickly. One consequence may be that perceptible temperature changes may not become apparent nearly so soon as has been anticipated. We may not be given a warning until the CO2 loading is such that an appreciable climate change is inevitable. The equilibrium warming will eventually occur; it will merely have been postponed".
The capacity for taking up heat is also discussed:
“…the upper-thermocline reservoir communicates effectively with the mixed layer on time scales of several decades. Therefore, the effective thermal capacity of the ocean for absorbing heat on these time scales is nearly an order of magnitude greater than that of the mixed layer alone”.
Damn, that sounds like a lot of heat storage to me. A lot of energy down there with nothing to do. Yet.
Anyway, it’s a good report addressing topical issues clearly. What it doesn’t address is why the oceans might have started taking up more heat recently, and there’s a good reason for that.
It was published in 1979.
It’s the Charney Report; “Carbon Dioxide and Climate: A Scientific Assessment”, drawn up by a National Research Council study group led by Jule Charney, at the behest of the US National Academy of Sciences. They also took advice from experts in the field, James Hansen and Richard Lindzen among them.
It is clear that even back then, climate science was aware of the role the oceans could play in the suppression of surface temperatures. Reading the report is fascinating, not least because these guys made quite a few educated guesses that have proved remarkably robust. Of course, the models they referred to were very crude, and temperature estimates were agreed more by committee than science, but the take-home points must not be lost: nearly a decade before the foundation of the IPCC, scientists were warning us very clearly of the potential danger in which we were placing ourselves. And they understood that the oceans could disguise the warming - which makes a mockery of claims that the hiatus was not anticipated.
If the potential role of the oceans was so clear, what then of climate sensitivity? Right now, in anticipation of AR5, there’s a lot of fevered speculation about the IPCC reducing the lower bounds of the range of temperature increase expected for a doubling of CO2. (This bonfire of the vanities fanned by several recent papers saying much the same thing. Haven’t these people heard of hubris?)
This argument may rather spectacularly miss the point. Claiming some comprehensive conquest of the ‘alarmists’ if the sensitivity is thought to be lower is a Pyrrhic victory over an academic issue. The question that must concern us is one science can’t really answer; for every degree of warming, how much will climate change damage us and the ecosystem we depend on, and how dear will be the cost, not just in money but in lives?
We’re short of incontrovertible evidence, but all over the world people are peering at the sky and ground, the oceans and the ice, and declaring that something seems amiss. We are not yet so estranged from our atavistic connections to nature that we can’t pick up on this unease, this tension in the natural world, in each other.
It doesn’t help when we read about so many other disquieting things happening elsewhere. Any one phenomenon can be adequately dismissed by the complacent as ‘natural variation’, but focussing on one issue at a time is a form of tunnel vision. It’s so many simultaneous things; together, they paint a much more compelling, truthful and dangerous picture. And so far, we’ve only experienced 0.8 degrees C of warming. Who in his right mind would dare suggest that 1.5 degrees of warming is safe?
In the end, we don’t yet know how the ocean's heat content has changed, but we know it has. We don’t know exactly how surface temperatures are being suppressed, but we know warming can't have stopped. We don’t know for sure what's causing the ice to melt so fast, although we have a pretty good idea that temperature might have something to do with it.
What we do know is that the same energy trapped and re-radiated by greenhouse gases last century is obliged to be trapped and re-radiated in this century too - and we’re still pumping out greenhouse gases like there’s no tomorrow (and that's not something you'd want to make into a self-fulfilling prophesy).
Climate change hasn’t stopped. True to its name, it’s changed - just like Charney knew it would back when he wrote his report. He posted it in 1979, so we’ll get it eventually, right?
A timely reminder that certain contrarian memes are false.
This bears repeating:
Also the absolutely central point that obsessing over TCR/ECS is a mistake. The true question is not climate sensitivity to 2xCO2 but ecosystem sensitivity to 2xCO2. Or higher.
The link to this report is this:
http://www.atmos.ucla.edu/~brianpm/download/charney_report.pdf
Otherwise you get the main page of the lab website.
This is a remarkable report, albeit short (kind of a summary for policymakers), in that it already contains most of the ingredients of this climate problematics, even if the models have been considerably refined. Moreover, more knowledge now means more uncertainties now, this is a kind of paradoxical law of science but quite logic, since many unknown unknowns have come out as known unknowns. More uncertainties mean also more fodder for contrarians, and in this context, it's important to keep eyesight on the big picture. Reading this report retrospectively greatly helps.
[GPW] Thanks for pointing that out - a missing tilde caused the problem - now fixed.
hank #9
You do not seem not seem to be aware the Charney Report was published over 30 years ago, before the stale rhetoric you are throwing around had even been thought of.
hank_:
In the first place, the hard data is already widely available. No special effort need be made by anyone who wants to find it. NOAA/NCDC, here at Skeptical Science, Real Climate, IPCC reports, and so on and so forth. Frankly, going around making statements implying that scientists have yet to "bring forth the hard data" sounds far more like spin in that light. In fact, it strikes me as practically an accusation of malfeasance.
In the second place, "damage control from the AGW faithful"?? Please. Pointing out (correctly) that the oceans are taking up 90+% of additional heat content from global warming isn't "damage control". It's called being accurate. If you want damage control, there are many accounts by climate pseudoskeptics of how Arctic sea ice has been "in recovery" any time over the last decade (it hasn't), or how a not-quite-statistically-significant-yet-still-positive surface temperature trend since 1998 counts as "no warming" or even "cooling".
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josiecki:
The NOAA/NCDC link posted by BBD works just fine for me (perhaps a mod fixed it if it was actually broken?). In addition, there just so happens to be a link to the Levitus et al paper in the Skeptical Science post discussing it. (Fancy that.) On to specifics regarding your inquiries:
Surface Temps vs. Heat Content
With regards to the prior focus on surface temperature anomalies, it must be said that these are much easier to measure than ocean heat content, we have longer-term reliable networks of surface temperature measurements, and as far as I am aware finding/developing adequate proxies for historical/paleo measurement is also much easier for surface temperatures than for ocean heat content.
That being said, we are getting better at measuring present and past ocean heat content, and it is IMO irresponsible to leave it out of the discussion, since as discussed it does represent heat storage of nearly 2 orders of magnitude more energy from global warming than do surface temperatures.
The Hockey Stick
For it's part, the "hockey stick" is in reality just a small, minor piece of the global warming body of knowledge. Insofar as it is a cause célèbre, at least in the last ten years, it is because of extraordinary efforts by denialists to attack and discredit it (which they have manifestly failed to do). It is also instructive since it shows an important part of the picture: the rapidity of contemporary warming.
Why the Atmosphere & CO2?
You ask "why are we looking at the atmosphere?" Then you basically answer the question yourself with "Isn't the atmosphere where we experience climate [weather]? [correction mine]"
The changes in weather due to warming, and its attendant effects on agriculture and other socioeconomic activity, is a very good reason to look at the atmosphere.
As for CO2, well, the physics shows that the reason all this warming is occurring, in the oceans and atmosphere and cryosphere, is because of the extra CO2 in the atmosphere. (This is kind of a "Well, DUH!" thing.)
What's It All About, Anyway?
In your final post (as of this writing), you make what is IMO a very revealing comment:
There are three major reasons why global warming is "kind of a big deal":
Suffice to say, the net consequence of these impacts severely impairs our ability as a species to continue to exist in the extraordinary state of physical affluence and numbers we currently possess. If we want to maintain something like what we have now, global warming must be dealt with.
As a final word, as I said to hank_, the data you are wondering about is out there, in great abundance. Start with the IPCC reports and work your way through the references. Browse posts here, or at Real Climate, and work through the references. The people who know their stuff and are regulars here are quite happy to help (although their reaction is strongly contingent on the perceived "adversarial" nature of the questions - many are the pseudoskeptics who have come and gone while "just asking questions").
And by "recent geologic history," Composer99 means the last 300 million years. Honisch even suggests that it may be unprecedented, period. The argument extends to atmospheric concentration, since atmospheric and oceanic carbon are tied tightly together. It's possible that life in general has never experienced a carbon spike of this rate, and if temp follows (likely), then life in general may experience an unprecedented rate of increase in temp. Evolution occurs at different speeds in different species. The longer an ecosystem is at effective equilibrium, the more integrated and tuned the ecosystem's species become. Rapid change across the spectrum of climate (temp, precipitation, wind, circulation, ice) means ecological dis-integration, and the species that evolve slowly are more likely to become extinct.
This may all sound rather alarmist and fanciful, and it may be hard to see from the perspective of a single human life, yet we are warming at between 10x and 30x the rate of PETM warming right now, and 55 million years ago there weren't seven billion human beings wrapped up in a complex, highly-integrated global economy, half living in cities and highly-dependent on the consistent delivery of cheap food, water, and energy. Physics says the warming will continue for centuries.
Here's the abstract from Johanson & Fu 2008:
"Observations show that the Hadley cell has widened by about 2°–5° since 1979. This widening and the concomitant poleward displacement of the subtropical dry zones may be accompanied by large-scale drying near 30°N and 30°S. Such drying poses a risk to inhabitants of these regions who are accustomed to established rainfall patterns. Simple and comprehensive general circulation models (GCMs) indicate that the Hadley cell may widen in response to global warming, warming of the west Pacific, or polar stratospheric cooling. The combination of these factors may be responsible for the recent observations. But there is no study so far that has compared the observed widening to GCM simulations of twentieth-century climate integrated with historical changes in forcings. Here the Hadley cell widening is assessed in current GCMs from historical simulations of the twentieth century as well as future climate projections and preindustrial control runs. The authors find that observed widening cannot be explained by natural variability. This observed widening is also significantly larger than in simulations of the twentieth and twenty-first centuries. These results illustrate the need for further investigation into the discrepancy between the observed and simulated widening of the Hadley cell."
That's already happening: significant changes to general circulation. During the PETM event, parts of general circulation flipped. You don't think something like that will have a significant, complex, and resonant impact on human agriculture?
How much of the excess heat absorbed in the oceans causes ice melt? This heat would melt ice floating on water. Melting of ice on land would keep the surface temperature from rising. In my high school physics class, I was told that it takes a large amount of energy to go from ice at 0 degrees centigrade to water at 0 degrees. Perhaps the melting of the floating ice and ice on land is keeping the tempeatures lower than projected?
somib, climate 'energy budget' studies take the energy used in converting ice to water into account. While this is a 'large' amount in absolute terms, it is actually only a small fraction (~2%) of the total energy from global warming... as can be seen here.
The thing is that atmospheric temperatures actually aren't "lower than projected". They are within the span of results produced by various model runs for the greenhouse gas levels we have observed. Climate scientists (and people capable of rational thought in general) have always known that fluctuations would occur... this denier idea that temperatures should rise in a continuous straight line is one of their dumber (and that's saying something) positions. There were temperature fluctuations before human induced global warming and no reason to imagine that they would stop after it.
Put another way... the difference between the 'slower atmospheric warming' observed over the past ~15 years and the 'rapid atmospheric warming' observed the 15 years prior to that is less than 1% of the total energy from global warming.
Shoyemore @12, I think you have been confused.
The effect of the ocean is that it has a very large heat capacity. Therefore, for a given change in radiative forcing it takes a long time (centuries) to reach the equilibrium temperature. Without the ocean, the Charney equilibrium temperature would be reached in a few decades at most. Consequently, in a situation of radiative imbalance, the ocean cools (or warms) the Earth temporarilly relative to what the temperature would be without the ocean, but by no more than (approsimately) the difference between the Charney Climate Sensitivity and the Transient Climate Response. In current conditions, that is about 1 or 2 degrees C.
That analysis ignores the effects of the existence of the ocean on the radiative balance itself. Absent an ocean, we would have no water vapour feedback, and no ice/snow or cloud albedo. Further, the the albedo of the areas currently covered by ocean would be that of desert (much higher). The net effect would be a much colder Earth, although I have not seen a study of by how much.
What I suspect you are thinking of is the difference between the actual temperature of the Earth, established by the radiative/convective equilibrium relative to the temperature we would have in the absence of heat transfer to the upper troposphere by convection. Absent convection, the Earth would indeed be much warmer. Indeed about 36 C warmer as you indicate, as shown by Manabe and Wetherald, and discussed here (see the top figure on page 9).
Yves at #2:
This reminds me of the missing-link argument of Creationists, where every evolutionary link found between two species simply raises from the Creationists claims of ever-more missing links, as if this somehow weakens evolutionary theory rather than supporting it.
The parallel between this and the 'gap'-finding by deniers of climate science makes my skin crawl when I think of it.
Tom Curtis @17,
My earlier comment has been removed, but it seems to me you are saying what I was trying to say, only you put it much better. I wll read and learn. Thanks. :)
"but all over the world people are peering at the sky and ground, the oceans and the ice, and declaring that something seems amiss"
When I was studying medicine in the 70's there was a well known effect that most of us experienced. When studying a particular disease it was common to experience some of the symptoms ourselves even though we were perfectly healthy. It was because we were made aware of these symptoms and so could easily ascribe them in ourselves, albeit for a short period. I'm sure you get my point.
If the air isn't getting warmer and we don't know what the oceans are doing despite your "certainty" that something is going on then, objectively, nothing is going on. You really can't go on about "the science" if empirical measurements don't support your position.
I'm having a hard look at the recent Fyfe, Gillett, Zwiers, "Overestimated global warming over the past 20 years" (Nature), with intent of doing so reported
and shared with the authors of the original (Zwiers). My emphasis is upon the statistical technique adopted, and my technical interest is how a Bayesian assessment of the same data might differ from their bootstrap-based result. This is just a note for future reference. I'm writing something up and sharing it for criticism by the authors, and, after I get their comments, I'll put it up on arXiv.org, with a link from http://hypergeometric.wordpress.com/.
an additional contribution to reduced heat in the near term can be derived from the cooler sea surface temperatures which reduces the amount of tropical thunderstorm activity which results in a decrease in moisture transport to the lower stratosphere. This effect is also compounded by a recent decline in stratospheric ozone. When there is less water vapor in the lower stratosphere the radiative forcing declines. this is seen as contributing to the reduction in atmospheric heating. Jeff Masters wrote an excellent article on this on his blog:
www.wunderground.com/blog/JeffMasters/stratospheric-water-vapor-decline-credited-with-slowing-global-warming
True enough, keitho, but of course if we do, in fact, know that the oceans are getting warmer, and we know that there's a top-of-atmosphere energy imbalance. Yes, there's uncertainty involved with both, and there's always the chance that aliens are manipulating our instruments or that we're brains in vats being fed a Matrix-like "reality." Science does not provide absolutes, regardless of the public clamoring for such. The question, then, is what happens when people who are convinced that we don't know what's going on encounter pretty solid data that says we do know? Do such people adhere to the standards they have for critical thinking in other people? The evidence--and there is plenty--suggests that some do and many don't.
@DSL . . If you hear hoofbeats don't start by looking for Zebras. (-snip-). Time for some deep thought wouldn't you say?
[DB] Off-topic & sloganeering snipped.
Keitho - Two points:
First: I don't have a position. Everything I've stated, or alluded to, is entirely consistent with current climate science. On climate change science, I don't need a 'position' any more than I need an opinion. I read the science, and simply report what it says, in full or in summary.
Second: The empirical evidence does support what I've said in my post. Surface temps are increasing, but at a slower rate than in previous decades. Oceans are warming, which we know by dint of an accelerating rate of sea level rise, and by sticking a thermometer in the water and reading what it measures.
(And thanks to CBDunkerson for stalwart services)
Keitho, models can always be improved. I wouldn't call model projections of surface temp "seriously wrong," though. After all, observed GMST is still within the 95% confidence range for CMIP3 ensemble modeling. True, GMST has swerved negative relative to the ensemble model mean, but if you can tell me what the ensemble model mean is worth in terms of science, I'd be much obliged. If you want seriously wrong, try Arctic sea ice projections. Ocean heat content is rising as expected. Sea level is rising at the top edge of projections. Changes to general circulation are happening as expected. Global ice mass loss is happening as expected. The physical mechanism of AGW, the greenhouse effect, remains unchallenged. Natural forcings are net negative over the last 50 years. Regardless, people continue to look for some way to say, "it's not happening."
Keitho:
Do you agree or disagree with the following statement by James Hansen:
"Climate is a complicated system but there is no change at all in our understanding of climate sensitivity [to carbon dioxide] and where the climate is headed," he said. "Our understanding of sensitivity is based on the Earth's history, not on climate models, and we have good data on how the Earth responded in the past when carbon dioxide changed. So there is no reason to change the forecast for the long term."
Source: Global warming has not stalled, insists world's best-known climate scientist by Damian Carrington, The Guardian, May 17, 2013
keitho, consider the following graph by John Nielsen-Gammon:
In it, he shows the linear trend for El Nino, ENSO neutral, and La Nina years seperately. Each trend is approximately the same, and none of the three trends shows any slow down. Given this, we must conclude that either:
1) The underlying temperature trend has remained unchanged over recent years, with any apparent slowdown being primarilly the result of ENSO fluctuations; or
2) The apparent slow down in the temperature trend is real, the apparent ENSO related patterns in the graph are coincidental, and ENSO has no influence on global temperature.
Which conclusion do you accept?
Because if it is not one, it is you who is running headlong from the data to preserve your favoured theory!
Another important fact to bring up whenever the models "fail to predict" a particular lull in the real-world data is that the climate models are not meant as forecasts like the weather. They are not modeling what the temperatures will be five years from now.
They are not concerned with the particular timing of any given event, be it a La Nina dominant decade or a huge volcanic eruption or a particularly lengthy solar minimum.
So of course the models don't "predict" the apparent pause from the last decade or so. They aren't supposed to be predicting any decade's metrics precisely. They are not a prognostication of what will happen in the real world the way a five-day forecast of the weather is supposed to represent what will really happen.
What they are supposed to do is model the physics that determine the underlying long-term patterns. The particulars of those experiments are determined by scenarios that are not expected to be crystal ball pronouncements; they are only expected to give certain inputs that the climate model will then churn through and produce an output based on our best understanding of how the climate works. You don't run a climate model to determine that there's a 70% chance of strong El Nino conditions this time four years from now, so dress light.
This lack of "weather forecast" functionality for climate models need sto be emphasized more often and more loudly. We often say that "climate is not weather" when it is time to discuss why a massive blizzard doesn't mean global warming stopped. We also need to start saying that "climate models are not weather forecasts." As long as people think that they are forecasts, we will hear this zombie argument moaning from the grave. It's bad enough that we all hear the lame refrain "They can't even predict the weather tomorrow, how are they supposed to predict the climate?"
Perhaps today, a few visits to the planet Wattsupia would serve the same purpose for somebody who was capable of scientific analysis. However, for those who are not, Wattupia would not be worth visiting.
I disagree with that. WUWT is not worth visiting under any circumstances.
Philippe, I disagree. I like to look at WUWT to see what is the latest thing they are now trying to deny. I find reading their posts and finding the errors to be a good way to pass my time.
Which is why I puzzle over the much-touted 2°C 'target' set by politicians. That amount of warming averaged across the biosphere means some places will get even warmer, some will be more static and some will cool. I have yet to read a credible argument showing how 2°C average warming will be an improvement over current temperatures, let alone how ocean acidification, due to concomitant CO₂e level increases in the atmosphere, will be a boon to terrestrial life.
I've been thinking about where, other than the deep oceans, we might have missed measuring some of the 'missing heat' lately and wondering if transformation of energy might be a factor. For example, more energy hitting the planet's surface means more surface heating... which means more/stronger thermal updrafts... which presumably means stronger winds. Similarly we might see changes in the rate of ocean currents. Wouldn't the energy required to move these masses of air and water at greater speeds ultimately be coming from the 'global warming' energy imbalance? Basically this is the transformation of light into heat and heat into kinetic energy. If so, has any research been done on how wind and ocean circulation have changed and how much energy would be required to drive these changes?
I haven't seen these factors listed in previous 'energy budget' analyses so they either somehow aren't applicable, are too minor to have a significant impact, have been included but generally not mentioned, or have been left out. Could some of the 'missing heat' be missing because it is no longer 'heat' at all, but rather has been transformed into motion?