W[h]ither Global Warming? Has It Slowed Down?

The so-called warming ‘hiatus’ over the past decade and a half is no reason for complacency on future warming. Mathematics teaches us that 15 years is simply too short a period from which to draw statistically valid conclusions.

Is global warming slowing down?

Is the past 10 to 15 years — which have seen little net change in the average surface temperature of the Earth despite ever-larger carbon dioxide emissions — an indication that climate change will not be as bad as previously projected? That the atmosphere is less sensitive to carbon dioxide than many scientists have concluded based on their understanding of the scientific evidence? That the warnings from those in-the-know are overblown and the world can keep burning fossil fuels?

These questions, percolating for a few months in the blogosphere, came to a head with a recent article in The Economist questioning climate sensitivity — the amount of surface warming expected for a doubling of atmospheric carbon dioxide levels. “The climate may be heating up less in response to greenhouse-gas emissions than was once thought,” read the article’s tagline. “But that does not mean the problem is going away.”

The second half of that conclusion is certainly right. Even if climate sensitivity is somewhat less than the IPCC’s median value of about 3 degrees Celsius, atmospheric carbon dioxide levels are increasing exponentially, so a smaller value merely buys an extra decade or two until the same amount of warming is reached.

But is the climate less sensitive to greenhouse gases like carbon dioxide and methane than has been forecast?

How Much of a Slowdown?

While there’s no doubt that the Earth’s recent surface temperature has not leaped ahead like it did in the 1980s and 1990s, it hasn’t exactly shown a flat trend over the last decade and a half.

Each of the three most-cited datasets estimating average surface temperature shows warming over the last 15 years (180 months): GISS: 0.11 C; HadCRUT4: 0.07 C; and NCDC 0.07 C (.2, .13, and .13 F respectively).

Like all measured numbers, these data have uncertainties, as discussed in the sidebar at the end of this article.

These increases are certainly less than the warming rates of the 1980s and first half of the 1990s of about 0.15 to 0.20 C (.27 and .36 F respectively) per decade. The earlier period may have provided an unrealistic view of the global warming signal, says Kevin Trenberth, climate scientist with the National Center for Atmospheric Research in Boulder, Co.

“One of the things emerging from several lines is that the IPCC has not paid enough attention to natural variability, on several time scales,” he says, especially El Niños and La Niñas, the Pacific Ocean phenomena that are not yet captured by climate models, and the longer term Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) which have cycle lengths of about 60 years.

From about 1975, when global warming resumed sharply, until the 1997-98 El Niño, the PDO was in its positive, warm phase, and heat did not penetrate as deeply into the ocean. The PDO has since changed to its negative, cooler phase.

“It was a time when natural variability and global warming were going in the same direction, so it was much easier to find global warming,” Trenberth says. “Now the PDO has gone in the other direction, so some counter-effects are masking some of the global warming manifestations right at the surface.”

In a 2011 analysis, researchers Grant Foster and Stefan Rahmstorf tried to mathematically separate out the influences of El Niños and La Niñas, volcanic eruptions that can lead to cooling, and a recent decrease in the radiance of the Sun. They found that the surface has an underlying average warming trend of about 0.15 C (0.27 F) per decade, presumably resulting from greenhouse gases.

The Oceans are Heating Up

The slowdown of surface warming has led many scientists to ask: If ever-larger carbon dioxide emissions are trapping ever more heat, where is the heat going?

The suspicion is that it’s been heating up the oceans, and recent studies have provided a much clearer picture. Direct measurements show the oceans still gaining heat.

Using data collected over the last decade, researchers Virginie Guemas from Météo-France and colleagues have shown a retrospective prediction at least five years in advance of the recent temperature pause, and they attribute it to increased ocean heat uptake, especially of the top 700 meters of the oceans, with 65 percent of it in the tropical Pacific and Atlantic Oceans.

Giving support to their finding is a forthcoming “reanalysis” by Magdalena Balmaseda and Erland Källén of the European Centre for Medium Range Weather Forecasts in the U.K., and Trenberth. Their research, by combining several sources of data with climate models, finds a sharp increase in ocean heating over the past decade, beginning shortly after the 1997-98 El Niño. “In the last decade, about 30 percent of the warming has occurred below 700 m, contributing significantly to an acceleration of the warming trend.”

In fact, their reanalysis finds that the total of all oceans actually lost heat during the 1990s, at a rate of about -0.26 Watts per square meter of ocean surface area. By contrast, the ocean gained about 1.19 Watts per square meter in the first decade of the 21st century, most in the top 700 meters. That gain, Trenberth says, is associated “with changes in the winds and changes in the ocean currents that are associated with a particular PDO pattern that has dominated in the 2000s.”

So it’s not surprising that there was a significant warming of the surface during the 1990s, but not over the past decade. This recent, large increase in ocean heat content is the best sign that the Earth is still undergoing an energy imbalance caused by an enhanced greenhouse effect.

About 90 percent of this extra energy goes into the oceans. But meteorologist Roger Pielke Sr. of the University of Colorado in Boulder says he would like to understand why more heat is going into the deep ocean. “Until we understand how this fundamental shift in the climate system occurred,” says Pielke, “and if this change in vertical heat transfer really happened, and is not just due to the different areal coverage and data quality in the earlier years, we have a large gap in our understanding of the climate system.”

These large changes in ocean content reveal that the Earth’s surface is not a great place to look for a planetary energy imbalance. “This means this heat is not being sampled by the global average surface temperature trend,” he says. “Since that metric is being used as the icon to report to policymakers on climate change, it illustrates a defect in using the two-dimensional field of surface temperature to diagnose global warming.”

A Shift in Aerosol Cooling?

Some have wondered if an increase in aerosols from China might be constraining the atmospheric warming.

Aerosols are small particles of smog, smoke, or dust that reflect sunlight before it reaches Earth’s surface. It’s long been known that sulphur dioxide aerosols from volcanic eruptions lead to a quick but temporary decrease in surface temperatures, as with the 1816 “Year Without a Summer” after the massive eruption of Indonesia’s Mt. Tambora a year earlier.

Indeed, an increase in aerosol emissions from the ramp-up of industrial production after World War II, at a time with few controls on pollution, are thought to be at least partly responsible for the hiatus in the rise in world temperatures from about 1945 to 1975. And the current aerosol forcing is substantial — an estimated cooling of 1.6 Watts per square meter, compared with manmade greenhouse warming of about twice that (see Figure 1 in Hansen et al. 2011).

James Hansen, just retired from NASA, wrote recently:

The rapid growth of fossil fuel CO2 emissions in the past decade is mainly from increased coal use…mostly in China with little control of aerosol emissions. It is thus likely that there has been an increase in the negative (cooling) climate forcing by aerosols in the past decade, as suggested by regional aerosols measurements in the Far East, but until proper global aerosol monitoring is initiated, as discussed below, the aerosol portion of the amplified Faustian bargain remains largely unquantified.

However, a recent study by Daniel Murphy of the Earth System Research Laboratory at NOAA, in Boulder, Colorado, found surprisingly little net change in aerosol forcing over the past decade. As air pollution shifted from the northern latitudes of the U.S. and Europe towards the equator in China and India, competing effects largely cancelled one another out — there is more sunlight nearer the equator, but its effect on aerosols is undone by its steeper angle, which means both that it travels through a shorter path in the atmosphere (so has less opportunity to scatter off aerosol particles) and less of its scattering is upward.

Average trend in aerosol concentrations (optical depth) over the last decade. Blue areas have less polluting aerosols; red areas have more.*

Murphy actually found that in the past decade aerosol concentrations have increased the most in the Middle East at about 20 degrees North latitude, perhaps because of dust. Aerosol concentrations decreased around 40 degrees North and around 40 degrees South, with the latter probably brought about by winds that scatter sea salts.

He cautions that his result applies only to aerosol’s “direct effect” — its scattering of sunlight — and not to its many “indirect effects,” such as the function aerosols serve as condensation sites for cloud formation. (The effects are roughly comparable in magnitude.)

“The message is simple,” he says. “For the direct effect, it matters more how much total aerosols there are than where you put them around the Earth.”

No Expectation of a Steady Temperature Rise

“Our expectation has never been that each year would be inexorably warmer than the previous year,” says Ben Santer, a climate modeler at Lawrence Livermore National Laboratory.

It’s simply scientifically incorrect, he says, to attribute the divergence of climate model projections and observations to an overestimation of the climate sensitivity. Santer says he sees several explanations of why climate model projections of surface warming may be differing from actual observations in the past decade or so.

“It’s certainly the case that we got some of the forcings wrong,” he says of the factors that specify the influence of any particular component of the atmosphere. “It’s likely we underestimated the true volcanic aerosol forcing, and may have underestimated the cooling effect of stratospheric ozone depletion.”

And Santer prefers the temperature measurements on the lower troposphere (below about 10 kilometers in altitude) derived from microwave emissions measured by satellites. His reasoning: they have true global coverage, and are independent from complicating factors like the urban heat island effects that influence thermometers on the surface.

Top: The probability that a modeled, unforced climate has a trend above what is actually observed (as of 2011). This chance drops below 5 percent only for trend lengths of at least 17 years, showing that the observed trends have a 95 percent chance of falling below natural noise only for time intervals that approach two decades. Bottom: Signal-to-Noise ratios for different timescales.**

“One would be foolish to rule out residual observational uncertainties given the history of the whole MSU [microwave sounding unit] saga,” he says, referring to the many years when scientists struggled to reconcile the surface and satellite measurements.

While the University of Alabama at Huntsville measurements were earlier biased low, the two satellite datasets have differed significantly in recent years, with the Remote Sensing Systems data showing essentially no warming in the lower troposphere over the past 15 years while UAH data show a statistically significant 0.12 C of warming in that time.

“There are very real and very large difficulties in generating coherent, homogeneous temperatures from two dozen drifting satellites,” Santer says.

Santer’s work in recent years has helped clarify how and when a climate signal can be found amid the noise of natural variability. Model studies found many 10-year periods that showed no surface warming, with even longer periods easily possible, much like there have been periods of several years where the Dow Jones Industrial Average has declined while moving higher over the decades. Santer’s group found that “temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature.”

The bottom line, Santer says, is “there are multiple, not mutually exclusive interpretations of modeled versus observed differences, and claiming that there is only one explanation is not scientifically accurate.”

“We study the signal. If others want to study the noise, let them.”

So Is There Anything to Explain?

Why did the ocean start taking up so much heat around the turn of the century, and will it continue? Calling it a “surprising finding,” Judith Curry of the Georgia Institute of Technology asks “Is this real, or an artifact of the reanalysis process? We don’t know,” she says, expecting the debate to continue.

Nor is it clear that recent surface trends are particularly unusual. “The term ‘hiatus’ is premature,” says planetary climatologist Raymond Pierrehumbert of the University of Chicago. “Maybe with another 10 years of data you’d say that’s something that needs explanation here.”

Pierrehumbert notes that the increase in carbon dioxide’s radiative forcing over any one decade is about one-fourth of a Watt per meter-squared, so if climate sensitivity is 2 C, the expected warming is only about 0.13 C (forcing increase divided by sensitivity). That can easily be swamped by natural fluctuations of 0.2 to 0.3 C from an El Niño or La Niña, and fluctuations from longer ocean cycles.

And, he says, “There’s really nothing in this that changes our estimates of climate sensitivity.” Calculation of that all-important number from the 20th century record is not possible, because the aerosol forcing is not well known, nor are the data for ocean warming up to the task.

“Any estimate of sensitivity requires all of the record and not just the last 20 years of it,” Pierrehumbert says. “The smaller the piece of it you take, the less certainty you have in your result.”

Nonetheless, he agrees that earlier warming may have been deceiving.

“I think it’s true that some rather sloppy discussion of the rapid warming from the 20th century has given people unrealistic expectations about the future course of warming.”

All the same, the warming effect of carbon dioxide is far down his list of topics that need further examination.

“Why would anyone seriously question greenhouse gases?” he asks. “They absolutely have a radiative effect, and no serious scientist thinks climate sensitivity could be much lower than 2 degrees Celsius based on the balance of the evidence.”

As noted above, with carbon emissions increasing exponentially, even a somewhat lower climate sensitivity simply does not buy much time to avoid a set level of warming.


Global warming — about 0.8 C or 1.5 F on the surface since the Industrial Revolution, with about twice this already committed to appearing in the future — is just getting started. Scientists have largely succeeded in digging its signal out of the climate noise, but that signal is still not obvious to many.

There have been hiatus periods in the past — from about 1945 to 1975, and slow downs in 15-year warming rates around 1994-1995 — and there will likely be more in the future. Those times of hiatus are consistent with human-caused warming in the natural world, and they are no reason at all to be lulled into complacency.

*Reprinted by permission from Macmillan Publishers Ltd: Nature Geoscience, Little net clear-sky radiative forcing from recent regional redistribution of aerosols, D. M. Murphy 6, 258–262 copyright (2013).
**Source: B.D. Santer et al, “Separating signal and noise in atmospheric temperature changes: The importance of timescale,”
Journal of Geophysical Research Vol 116 D22105, doi:10.1029/2011JD016263, 2011. Used with permission.

*The headline of this piece was edited May 9 to bracket the letter “h” in “Wither,” clarifying the deliberate intent at a double meaning.

The Temperature Lately

What has been the actual warming over the past 15 years? The answer has several layers of complexity.

Of the three most cited datasets that estimate average surface temperature, all show warming over the last 15 years (180 months):

GISS: 0.11 C
HadCRUT4: 0.07 C
NCDC: 0.07 C

while the change in the temperature of the lower troposphere over the same period is

RSS: -0.03 C
UAH: 0.12 C

These numbers are estimates based on fitting a straight line through the data, and each comes with a level of uncertainty that indicates how much the value’s estimate differs from the “true” value. The simplest (but naive) estimates of these uncertainties are:

GISS: 0.11 ± 0.06 C
HadCRUT4: 0.07 ± 0.06 C
NCDC: 0.07 ± 0.06 C

RSS: -0.03 ± 0.08 C
UAH: 0.12 ± 0.08 C

Here the uncertainties give the bounds of the 95 percent confidence level — that is, we can be 95 percent sure that the “true” amount of warming as measured by GISS is between 0.05 C and 0.17 C.

But his method is “naive” because it assumes each month’s temperature is independent of those before and after it. In reality the climate system has a great deal of inertia, and any given month is more likely to be warm (or cold) if the previous month was warm (or cold). This “autocorrelation” increases the uncertainties significantly given that there are in effect many fewer independent data points.

The calculation of uncertainties in the presence of autocorrelation is mathematically involved. It was adapted for climate science about 13 years ago; the blog Skeptical Science has a useful calculating tool based on the method of Grant Foster and Stefan Rahmstorf. It shows that the uncertainty that accounts for autocorrelation is, for a relatively short interval like 15 years, several times higher than the naive uncertainty.

For example, including autocorrelation gives, for the GISS data, a 15-year trend of 0.07 ± 0.14 C per decade, so the warming in that time is GISS: 0.11 ± 0.21 C

The large uncertainty simply shows that very little can be said about the “true” warming over such a short time period, when climate inertia is properly considered. In fact, in this case the autocorrelation is so strong the GISS data effectively has only about 11 independent degrees of freedom instead of the naive 180 (=15´ × 12) present in 15 years worth of monthly data points.

Uncertainty from the statistics, from climate inertia, and from climate noise all show that 15 years is simply too short of a time period when making judgments about climate.

So the lesson of the mathematics is: 15 years is simply too short of a time interval from which to draw statistically valid conclusions, which are heavily influenced by “end point” effects. This is why most climate scientists prefer to draw their conclusions from 30 years’ worth of data or more.

Back to article

David Appell

David Appell is a science writer living in Oregon and a regular contributor to Yale Climate Connections. (E-mail: david@yaleclimatemediaforum.org, Twitter: @davidappell)
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95 Responses to W[h]ither Global Warming? Has It Slowed Down?

  1. Mike Smith says:

    This article,with the exception of Judy Curry, only quotes believers in catastrophic global warming. This is unfortunate. A more balanced approach would have emphasized the following points:

    Science works by offering a hypothesis. The Intergovernmental Panel on Climate Change and others did that by predicting, year-by-year, future temperatures based on their estimates of climate sensitivity. Temperatures are now well below their predictions. If they can’t get it right for 15 years, it certainly calls their 50 year predictions into question.

    By offering explanations of the incorrect year to year forecasts by saying, “Model studies found many 10-year periods that showed no surface warming, with even longer periods easily possible” is moving the goal posts. Now, it may be that Dr. Santer’s new hypothesis is correct but that has nothing to do with the original forecasts being wrong.

    Thirdly, there has been no increase in hurricanes or tornadoes as predicted by climate science.

    More and more, it appears that global warming is not the catastrophic threat once thought. Climate science would increase its credibility by acknowledging its incorrect forecasts as a basis for going forward.

    • Evan D says:

      Sorry, what?

      • James Gerard says:

        Demands for “balanced reporting” are often nothing but an attempt to elevate ignorant ideas to a level of importance.

        This is a well known tactic of those who wish to obscure science and fact.

        Read the excellent book “Merchants of Doubt” by Naomi Oreskes and Erik Conway.

        Some of the same bogus “scientists” who invented the campaign to discredit the science showing that cigarettes cause cancer recently changed to denial of Climate Change.

        These people are nothing but liars for money.

        Oreskes and Conway name names in a seriously well documented book.

        The simple facts of disappearing Arctic sea ice, melting permafrost, disappearing glaciers, and migrating plant and animal species are among the overwhelming evidence that can not be ignored or covered up.

    • David Appell says:

      Mike: I asked for an interview of two prominent contrarians, and neither responded.

      • davideisenstadt says:

        GISS: 0.11 ± 0.06 C
        HadCRUT4: 0.07 ± 0.06 C
        NCDC: 0.07 ± 0.06 C
        RSS: -0.03 ± 0.08 C
        UAH: 0.12 ± 0.08 C

        really? really?
        all of your bleating about a continued warming trend boilds down to 7 one hundedths degree celsius +/- 6 one hundredth of a degree?
        over a decade?
        really? like temperature data is reliable to that resolution?

        oh yeah…the real trend to watch is 0.11+/- 0.06
        sorry david, you lost me.

        • Albert N. Hopfer III says:

          If 15 years is too short a time, so must 1977 to 1998′s 22 years. Yet, National presidents and World bank(s) are doing just that, with the blessings of those saying 15 years is too short.

    • Jim Pettit says:

      “A more balanced approach”? No, thanks; false equivalence is killing progress. Since several studies have shown that roughly 97% of active climate scientists agree that man’s activities are warming the planet, throwing both Judith Curry and Roger Pielke, Jr., in the mix seriously overrepresents the dissenting side of the debate.

      • Steve says:

        Dr. Curry is part of the 97%…

        • asherpat says:

          “Roughly” 97%? Just like the predictions of the IPCC models were “roughly” wrong, always erring on the upside?

          • Neill says:

            The 97% is actually only 75 out of 77 scientists, who responded out of a polled group of over 3000.


  2. Ken Orski says:

    How do you expect the average layman to comprehend all this arcane argumentation. No wonder the general public ranks “global warming” at the very bottom of public concerns!

    • Jim Pettit says:

      So, you deny the scientific evidence because you misunderstand it? I get it. Looks like more education is in order for you.

  3. James Evans says:

    “Mathematics teaches us that 15 years is simply too short a period from which to draw statistically valid conclusions.”

    It’s a shame you weren’t there to point that out at Hansen’s 1988 Senate hearing.

    “‘But that does not mean the problem is going away.’
    The second half of that conclusion is certainly right. Even if climate sensitivity is somewhat less than the IPCC’s median value of about 3 degrees Celsius, atmospheric carbon dioxide levels are increasing exponentially, so a smaller value merely buys an extra decade or two until the same amount of warming is reached.”

    To what level did you study mathematics?

    • Toby says:

      The first scientist to predict a period of global warming was Professor Wallace Broecker in 1975: http://blogs.ei.columbia.edu/files/2009/10/broeckerglobalwarming75.pdf

      Dr Hansen did not base his Seante statement on 15 years of data – more like 150.

    • David Appell says:

      James: If CO2 is increasing exponentially with a doubling time of D, and if temperature change is proportional to the logarithm of CO2, then the temperature change after a time t is


      where S is climate sensitivity.

      Now suppose climate sensitivity is S2 instead of S1, where the difference between them is small compared to either. Then the difference in time (t2-t1) to reach a certain amount of warming is approximately

      delta(t)/t1 = delta(S)/S1

      which is a small number.

  4. Thanks so much for this report. I wish you had done more than mention El Nino Southern Ocean oscillations (ENSO):

    “That can easily be swamped by natural fluctuations of 0.2 to 0.3 C from an El Niño or La Niña, and fluctuations from longer ocean cycles.”

    Because I hear we are now in a condition humorously called a “La Nada” state – not quite El Niño or La Niña – I understand that when we flip to an El Niño condition, the heat impact will be amplified greatly.

    I hope you discuss this further, because it seems like it just begins to call forth the real issue: “How bad? and how soon? “

    • James Evans says:

      “How bad? and how soon?“

      That’s in your head. Please keep it there.

    • David Appell says:

      Richard: While the next El Nino will likely lead to increased surface temperatures, pointing them that as a sign of manmade global warming would be just as inaccurate as pointing to La Nina cooling as evidence against it.

      El Ninos and La Ninas are “weather,” but in the ocean. For short time intervals (10-15 years) they are going to skew the trend one way or the others. That gives a misleading notion of climate change, one direction or the others. This is why most climatologists insist on 30 years or more to diagnose true changes in climate.

      • Bruce says:

        Yes, but it will provide more evidence that ENSO and other MDOs are the drivers of these short cycles, and validate the underlying long term trend.

        • David Appell says:

          Bruce: I don’t see any doubt that ENSO is a driver of global temperatures, with a lag of maybe 6 months, and hence of global averages over some “short” period of time.

  5. John Garrett says:

    Mayge…, just maybe, it’s time for climatology to admit that it doesn’t understand the climate system.

  6. John M says:

    Re 15 years being “enough”…

    From the Summary for Policymakers from Working Group I of the 2007 IPCC Fourth Assessment Report:

    “Since IPCC’s first report in 1990, assessed projections have suggested global averaged temperature increases between about 0.15 and 0.3°C [0.27 and 0.54°F] per decade for 1990 to 2005. This can now be compared with observed values of about 0.2°C [0.36°F] per decade, strengthening confidence in near-term projections.”

    If in 2007, 15 years of data were enough to “strengthen confidence”, what should 15 years of data do to our confidence in 2013?

    Or is 15 years enough only when it’s…enough, and not enough when it’s…not?

    • Toby says:

      1990 was 23 years ago, not 15. And the basis for the predictive success is the 0.6C rise since about 1980 – about 0.2C per decade.

      “Ye can nay change the laws o’physics, Capt’n”, as a famous starship engineer once said.

      If natural variability was at the root of the warming, the planet would have started cooling rapidly and Arctic Ice would be recovering. Neither is happening, meaning denier predictions to the contrary are failures on an epic scale.

      • HR says:

        “If natural variability was at the root of the warming,”

        “[then] the planet would have started cooling rapidly and Arctic Ice would be recovering.”

        There is no reason why your second statement should follow your first unless you understand the proposed natural mechanism(s) that might be controlling this and can show it has reversed sufficiently to cause cooling. The whole point of this article is that natural variability can be used to explain the pause/hiatus/whatever in warming at the surface. The bigger question for me is what impact that has on our understanding of past trends. The rapid warming between the mid-70s and mid-90s has generally been attributed to forcing there has to follow that the confidence in that particular belief is less solid.

    • Tony says:


      From your quote, the IPCC report merely stated that the 15 year period of observed values “strengthens” confidence in those near term projections. Note that this article talks about climate scientists being cautious about drawing “conclusions” on less than 30 years worth of data.

      Having said that, this article mentions ways in which the slowing of warming (but still warming) over the last 15 years can be explained (and pointed to research that shows this). Perhaps you missed those.

    • John M says:

      Neither one of you answered my question:

      “If in 2007, 15 years of data were enough to “strengthen confidence”, what should 15 years of data do to our confidence in 2013?”

      • David Appell says:

        One of the things I tried to bring out in this article is that, prior to 2000, some people may have been overestimating AGW based on observed trends, at a time when ocean cycles were adding to global warming instead of (like now) subtracting from it.

        • HR says:

          Given the abuse many sceptical scientist get for suggesting the consensus is built on false confidence shouldn’t you be less circumspect here. Name and shame those people you think were obviously alarmist in the past so we can all be aware of their tendency toward shallow, premature or biased conclusions.

        • John M says:

          Yes, despite the fact that we’re constantly told that climate models are not “fitted” or “tuned”, it’s becoming evident that they were suspiciously close to the temperature record during the latest warm phase of the PDO (and were unable to track the global temperature well during the previous warm phase of the PDO).

          In fact, it’s worth remembering that after a string of El Ninos in the 90s (common during the warm phase of the PDO), there was quite a bit of blather about El Ninos being caused by AGW.

          Sort of a mirror image of the current arguments that AGW is causing a shift in the jet stream that’s leading to cold weather.

  7. MarkB says:

    Climate scientists seem to be very good at post hoc explanations and ‘predicting’ things after they’ve happened. Every climate scientist now tells us that it is perfectly normal to have no warming for over a decade. Funny thing – they didn’t say this BEFORE it happened. And – watch the pea – they confound the probability of having a decade-long ‘hiatus’ of warming with the probability of having a decade-long hiatus in the FIRST decade of the prediction time.

    When the data doesn’t match your model, you can do two things. You can question your model, or you can twist yourself into knots to save your model. Some climate scientists – the only ones we hear from – choose the latter.

    Please note – I make this prediction ahead of time, unlike climate scientst/activists: when we get to 17 years of no significant warming, the Usual Climate Suspects will announce that they’ve looking into their crystal balls, and it really take 27 years before we know anything. Nice gig. I’m sure a lot of salesmen would like to get paid without their bosses being able to see their sales figures for decades.

    • Jim Pettit says:

      Before we get to 17 years of no warming, we need to get to, say, one year of no warming–and that hasn’t happened yet. The oceans are continuing to heat at a rapid rate–a rate much faster than the surface temperature. Looking at only one aspect of global temperatures and declaring a pause is like sticking your head in the refrigerator on a summer day and declaring it’s cold enough in the house to turn on the heater.

    • David Appell says:

      Mark: All sciences, throughout history, modify and reshape their ideas as new or better data comes in — all of them.

      Why should climate science be any different?

      • HR says:

        Could you maybe enlighten us on what position ‘consensus’ plays in science in light of that statement?

      • Shiv says:

        Until the idea is on solid grounds, we dont accept predictions based on those unproven ideas. Nor does anyone call the science or idea settled.In most cases, what happens is that we expand on proven science. For example, no one is retroactively revising and reshaping gravitational force equation GMm/r2 every year. If that were the case, we would never rely on these equations to do the million things we do with these equations reliably year in and year out. Rather, these ideas were proven with large number of observations _before_ they were accepted as proven relationships and used for predictions. Climate science today is at best at its infancy. It isnt even able to present a coherent model of climate on earth, much less capable of predicting 100 year climate. If we did physics or engineering this way, there would be chaos on the planet, not to mention large scale death and destruction

    • JamesG says:

      The oceans are not warming either unless you count the guesstimates from before accurate measurements were available. This unexpected anomaly of non-warming of the ocean is precisely why the “missing heat” problem was first raised by Trenberth. Now sure he proposes the heat is going in the deep ocean and sure someone has bodged up a 700m to 2000m ocean temperature graph that purports to show this deep ocean heat capture based on roughly 3 data points but only the pessimistic/gullible are fooled. In reality, as Pielke said in his fuller statement, it is utterly unphysical to suggest that heat can bypass the top layers of ocean and head straight to the murky depths. Remember that when they tell you it’s all based on “simple” physics. Simple physics tells us the 700m-2000m graph MUST be wrong. Occams razor suggests there is no missing heat because the hypothesis is wrong.

    • Villy Søgaard says:

      I followed a course on basic climatology in the late 1970s. The statistical arguments for a 30 year perspective were explained to us back then – long before the debates over global warming set in.

  8. Aldous says:

    “Global warming — about 0.8 C or 1.5 F on the surface since the Industrial Revolution, with about twice this already committed to appearing in the future — is just getting started.”

    And how has humanity fared over this period of warming so far? Hmm? We are living in a veritable golden age of human flourishing. Never has life expectancy been longer, never have we been healthier or less at war. Never have we been better fed, more literate and wealthy.

    And still, wave after wave of Malthusian bed-wetters persuade the public we’re “just barely hanging on” and certain doom is around the corner. I don’t deny radiative physics, just the economic and historical literacy of those who are most loudly advocating alarm.

    • David Appell says:

      Aldous: The question isn’t so much what is the ideal temperature for human civilization, but how adaptable are we, other species, and ecosystems to a rapid changes in temperature, sea level, etc.

      Current warming rates are about 50 times larger than during the PETM, which saw many species go extinct.

  9. John Brookes says:

    Thanks for a nice discussion.

    • Jp says:

      “Thanks for a nice discussion.”, spoiled by the usual echoing empty vessels.

      • HR says:

        “spoiled by the usual echoing empty vessels” = as long as you say what I want to hear.

        This discussion would have no meaning if it wasn’t for the critics of the consensus. The empty vessels are those that believe new data has no impact on our understanding.

  10. R. Shearer says:

    There’s this bright yellow thing in the sky that comes up every morning.

    • Boo says:

      Oh My God!! The bright yellow thing? Who’d a thought it?!?!? I can’t believe no one in the history of climate science ever thought about the sun having an impact!

      Oh Wait …. They DO. And it does not account for the current warming.

      • JamesG says:

        Though strangely it does account for the coming and going of ice ages.

        • Boo says:

          Actually, it does not. That would be the Milankovitch cycles, it has nothing to do with changes in the sun.

    • David Appell says:

      R. Shearer:
      Nowadays solar irradiance is measured daily by satellite.

      For example, here is the data from LASP in Colorado:

      Solar irradiance has decreased slightly in the last decade, and that’s been taken into account. It’s never a huge amount, since, to first order (from the Stefan Boltzmann Law) dT/T = (1/4)(dS/S), where S is solar irradiance.

  11. MikeR says:

    “no serious scientist thinks climate sensitivity could be much lower than 2 degrees Celsius”. Can I gather that you-all are willing to admit that plenty of serious scientists might think that climate sensitivity is somewhat lower than 2 degrees Celsius, as James Annan suggested recently is becoming much more likely? Though you spent a whole article denying the possibility, that would be very good news indeed.

    • David Appell says:

      That was a direct quote from Raymond Pierrehumbert.

      • MikeR says:

        It was a direct quote, but the implication was what I was pointing out. And that implication is counter to other statements in the article, such as “It’s simply scientifically incorrect, he says, to attribute the divergence of climate model projections and observations to an overestimation of the climate sensitivity.” The point of the whole article is that we should not be reducing the sensitivity, because there are other possible explanations for the slowdown.

        And that is just wrong from a Bayesian point of view. The higher sensitivities may still be right, but their likelihood must be reduced by events that are more likely according to lower sensitivities.

        • David Appell says:

          MikeR: You simply can’t calculate climate sensivity from < 2 decades fo data.

          • HR says:

            I don’t think anybody is asking for CS to be calculated solely from the last two decades. But you simply can’t ignore the last two decades of data when calculating sensitivity.

            The point is when you include the hiatus (with the rest of the data) then some climate scientists seem to believe best estimates of CS should be shifted lower

        • JamesG says:

          Bear in mind the last two decades have had the largest increase in carbon dioxide. If CO2 is going parabolic and the temperature is going the other way then the hypothesis is plain wrong. If suddenly the only money available was for studying natural variability, everyone would be proposing lots of previously unconsidered mechanisms that diminished mans role in climate. Thats how the funding bias works! The only thing that has come from the discussion above is that they don’t have a clue about the extent of AGW, but as long as they are paid to look for it they won’t be letting the idea die a natural death.

          • David Appell says:

            Scientists simply do not have all the information they need to make a good calculation of climate sensitivity based on the last 2 decades.

            In particular, they are missing
            1) how much heat has gone into the deep ocean (lower than 2000 meters)
            2) how much aerosols (soot, etc) have been emitted into the lower troposphere, and where

            More information is needed — Kevin Trenberth, in particular, has been making this point in the last few years.

    • MikeH says:

      “somewhat lower than 2 degrees Celsius, as James Annan suggested recently ”

      That is a lie. And easily shown to be one.


    • sully says:

      ‘sensitivity is somewhat lower than 2 degrees Celsius, as James Annan suggested recently is becoming much more likely’

      Except, Annan did NOT suggest it’s the correct sensitivity. Annan holds that sensitivity is about 2.5 degrees C, and unlikely to be above 4 degrees, which he (correctly) asserts in his 2012 paper with Hargreaves, is *wholly consistent with previous models*. The verbiage about <2 degrees that you cite merely indicates that the lower numbers can't be ruled *as strongly* as was thought before. That's all. Here are the very words from the paper's conclusion:

      "We have found evidence in the PMIP2 ensemble of a relationship between LGM cooling in the tropics, and equilibrium climate sensitivity. Based on this result, we estimate climate sensitivity to be around 2.5°C with a high probability of lying below 4°C."


  12. AlecM says:

    We are at a very interesting point in the debate. There is a discussion on the Spencer Blog about imaginary ‘back radiation used to justify 134.5 W/m^2 imaginary heating in the models. This article appears to be part of that defence process.

    Pierrehumbert’s 2011 paper is worth reading**, he doesn’t dwell on the Aarhenius mechanism which any professional with decent heat transfer knowledge immediately realises is bunkum. Instead he cleverly used the ‘CO2 bite’ in OLR plus slipping in the claim that this accounts for a third of the GHE thus cleverly cementing in the public psyche the 134.5 W/m^2 created artificially within the models. However, he does this with quite clever weasel words.

    Thus ‘the team’ is desperately defending the phoney heating caused by phoney boundary conditions. The claim that this is being put into the oceans because it doesn’t appear elsewhere is based on 0.9 W/m^2 [2009 data]. However, they are really using this as a way of dragging the attention of the public away from a much larger error – where does the 134.5 – 0.9 W/m^2 go?

    My point, that it never existed in the first place,is now ignored rather than being furiously countered with claims that Kirchhoff’s Law of Radiation applies at ToA when it can’t!


    PS you can easily explain how the ‘CO2 bite’ is bypassed from the lower atmosphere.

    • David Appell says:

      Alec: Downwelling infrared radiation, of “backradiation,” is real, and has been measured:

      “Radiative forcing – measured at Earth’s surface – corroborate the increasing greenhouse effect,” R. Phillipona et al, Geo Res Letters, v31 L03202 (2004)

      “Measurements of the Radiative Surface Forcing of Climate,” W.F.J. Evans, Jan 2006

      “A method for continuous estimation of clear-sky downwelling longwave radiative flux developed using ARM surface measurements,” C. N. Long and D. D. Turner, Journal of Geophysical Research, vol 113, D18206, doi:10.1029/2008JD009936, 2008

      • AlecM says:

        I do not dispute the pyrgeometer measurements. Unfortunately, they are misinterpreted. This is a serious problem because 100s of man years have been wasted in Climate Alchemy’s search for ‘back radiation’.

        What a pyrgeometer outputs is the S-B predicted power for the optical pyrometer temperature of the emitter. This is not a real energy flux but the potential flux to the zero point energy of a vacuum.

        A radiation field can only do thermodynamic work if it interacts with another radiation field. At any point in space the volumetric heat generation rate of matter is the integral over all wavelengths of the negative of the instantaneous monochromatic radiative flux density gradients.

        This is the difference of S-B equations. What happens when you get higher humidity and higher [CO2], as was measured, is zero change of net surface IR. This is from a quirk of physics which means that at an optical heterogeneity, the thermal IR band for a self-absorbed ghg appears at the black body level so it and the black body surface IR mutually annihilate.

        Thus there can be no CO2-AGW from this cause, nor any other, neither does the increased humidity cause any increase in surface IR. You just get the 23 W/m^2 absorbed by water vapour side bands plus trace gases, none of them self-absorbed, and 40 W/m^ to space via the atmospheric window.

        Also the OLR CO2 bite is bypassed by lower atmosphere processes. In short, for a given insolation the atmosphere can cope with any level of CO2 whilst maintaining near constant temperature. The effects of insolation change and cloud area are also damped. Ice age bistability is the presence or absence of biofeedback.

        The climate models exaggerate GHG absorption of surface IR by a factor of 6.85 [2009 Energy budget], because of incorrect boundary conditions, then offset the extra warming by extra cloud albedo.

        • John Brookes says:

          Hmmm. Let me see. Either hundreds of man years have been wasted, or AlecM is wrong.


        • David Appell says:

          Alec wrote:
          What a pyrgeometer outputs is the S-B predicted power for the optical pyrometer temperature of the emitter. This is not a real energy flux but the potential flux to the zero point energy of a vacuum.

          I don’t even know what this means, nor do I think these reading have has anything to do with the zero point energy of the vacuum.

          They are measuring radiation, not a vacuum.

        • David Appell says:

          A radiation field can only do thermodynamic work if it interacts with another radiation field.

          This is utterly false, as the photoelectric effect shows: a photon does work on the electron in a solid material.

          I’m sorry, but I don’t any real physics in your arguments.

  13. Nic Lewis says:

    You say that the oceans are warming up, but the only figure you quote is from the Balmaseda and Källén “reanalysis” – a model-based estimate:

    “By contrast, the ocean gained about 1.19 Watts per square meter in the first decade of the 21st century, most in the top 700 meters.”

    That equates to 0.84 W/m^2 over the whole of the Earth’s surface. Balmaseda and Källén claim that some 70% of this heat gain (0.59 W/m^2) was in the 0-700m layer.

    May I ask why you didn’t give the much more relevant observational estimates that exist, which is what I believe to be normal in science? You do give a link to the graphs at the NODC/NOAA website of updated Levitus 2012 data, but no numbers.

    For the record, the increase in 0-700 m ocean heat content (OHC) over the first decade of the 21st century (2000 to 2009, I assume) per the updated Levitus et al 2012 annual data was 0.29 W/m^2 over the Earth’s surface, only half the Balmaseda and Källén figure. The corresponding Levitus 2012 estimate for the 0-2000 m layer (based on 5 year running mean data, annual data only being published from 2005 on) was 0.50 W/m^2, only 60% of the Balmaseda and Källén figure. Levitus 2012 found no significant warming between 2000 and 3000 m.

    Supporting of the Levitus 2012 estimate for 0-3000 m warming, Loeb et al (2012) estimated the Earth’s total radiative imbalance over 2001-2010 as 0.50 W/m^2. Their estimate included heat uptake by land, atmosphere and melting ice and in the abyssal ocean as well as the 0-3000 m layer. They combined satellite measurements of top of atmosphere radiation with OHC estimates from PMEL.

    If you use the Levitus 2012 and Loeb 2012 estimates of heat uptake, and observationally-derived estimates of aerosol cooling, you will find that an energy budget/ heat balance estimate of climate sensitivity based on changes from the 1860s/1870s to 2000-2010 comes out some way below 2°C. Personally, I would place far more reliance on an estimate of climate sensitivity arrived at by this robust method than on estimates from GCM simulations or paleoclimate studies.

    • David Appell says:

      Nic: The NOAA page on ocean heat content that I linked to itself has links to the data.

      The Balmaseda et al numbers (their Table 1) are per unit area of the global ocean, not for the entire Earth’s surface area, so they need to be divided by 1.41 to compare.

      Balmaseda et al discuss the differences between their results and other measurements. They write, “The total depth warming is also comparable with that in the global OHC from L12 [Levitus 2012]…. Compared with the 5-year L12 product, [the reanalysis] shows more distinctive interannual variability, making it easier to identify the impact of volcanoes and ENSO. Other differences arise from the analysis procedures and datasets used, as discussed in the methods section S01.”

      • Nic Lewis says:

        David: I realise that the NOAA page has links to the data, but few readers will download it and calculate the OHC change, and so are unlikely to realise that it is far lower than Balmaseda et al’s figure.

        I know the Balmeseda figures are per unit area of the global ocean. That is why I adjusted their 1.19 W/m^2 figure for the full-depth ocean to 0.84 W/m^2 per unit area of the entire Earth’s surface. The corresponding entire-Earth’s surface figure for the 0-700 m layer is more accurately stated as 0.64 W/m^2 rather than the 0.59 W/m^2 I gave, which was based on their “some 70%” statement. So the discrepancy with the Levitus 2012 observational estimate of 0.29 W/m^2 is even larger.

        Balmethsda’s claim that ““The total depth warming is also comparable with that in the global OHC from L12 [Levitus 2012]” appears to be incorrect, at least in relation to the 2000s.

    • David Appell says:

      By the way, Loeb et al didn’t include include ocean heat changes below 1800 m; Levitus et al didn’t give data below 2000 m.

      • Nic Lewis says:

        David: You are mistaken regarding Loeb

        Loeb 2012 states that they combine the PMEL/JPL/JIMAR “Argo-only estimate from 0 to 1,800m with estimates of smaller heat uptake terms from warming of the deep ocean, land and atmosphere, as well as melting ice.”.
        That is in line with what I wrote.

        I agree that Levitus 2012 made no specific estimate about finding no significant warming between 2000 and 3000 m. I should have attributed that statement to Chapter 3 of the leaked AR5 WG1 SOD:
        “Nevertheless, there is sufficient information to conclude that the warming of the global ocean from circa 1992–2005 is likely not distinguishable from zero between 2000 and 3000 m depth”.
        The reference cited was Kouketsu et al, 2011.

    • HR says:

      “way below 2°C.”

      Nic given you’re demanding precision from David would you mind being a bit more accurate here. What is the actually figure? “way below’ could mean anything.

  14. Girma says:

    Has it slowed?


    Here is the observation:


    The climate pattern indicates no warming until about 2040.

    The pattern also indicates an annual global mean temperature of about 0.2 deg C in the next two decades.

  15. Paul Quigg says:

    In 2000 I created a graph correlating the path of carbon dioxide emissions,carbon dioxide concentrations and global temperatures from 1850 to 2000, with 1850 and 2000 as the base years. Emissions and concentrations showed a basically steady exponential growth from 1850 to 2000, global temperature figures were all over the place,up and down, crossing the emission and concentration lines numerous times. Since 2000 the temperature line has lost it’s rapid rise and turned almost horizontal, while emissions and concentrations have continued their exponential growth. What does this trend tell us, NOTHING. While scientists jump through hoops trying to understand this lack of correlation we must face the fact that we really know very little about the climate. I will be 100 in 2031, we should know something by then.

  16. Arno Arrak says:

    This article attempts to defend the indefensible and borders on pseudoscience. Important scientific facts and observations are ignored and the most important theory that explains the greenhouse process, that of Ferenc Miskolczi, is not even mentioned. To start off, the slight warmings in the twenty-first century are of dubious quality because of the ENSO oscillations that restarted in 2008. Judging by the satellite curve, there is no reason to believe that any warming at all has been taken place this century. The three ground-based curves referred to have been manipulated and cannot be trusted. They were all computer processed, but unbeknownst to the owners their software had unanticipated consequences. Namely, it left sharp upward spikes at the beginnings of most years. These spikes are in exactly the same places in all three, supposedly independent, data-sets. To see them clearly you should first outline the global trend with a semi-transparent colored band as shown in my book. In addition to these computer processing marks, I had found that the ground-based curves showed a phony temperature rise in the eighties and nineties where global mean temperature stood still for 18 years. I published that in my book “What Warming?” but was totally ignored. But last fall, something strange happened. All three data-set masters had decided to revise their eighties and nineties data to look very much like the satellite data which does not have any warming there. Nothing was said about it but the fact that the same correction appeared in all three of these data-sets that span the ocean tells me that they knew very well what they had been doing. Hence, I recommend that only satellite data should be used from 1979 on. The eighties and nineties according to satellites were a period of ENSO oscillations showing five El Nino peaks. The middle one is the El Nino of 1988 which Hansen reported to the senate as peak global warming. Six months after his talk that El Nino was gone and the La Nina that appeared in its place lowered global temperature by 0.4 degrees. To find the global mean temperature of an ENSO oscillation you have to put a dot in the middle of each line connecting an El Nino peak with its neighboring La Nina valley. When this is done, connect the dots. Doing this for the eighties and nineties you get a horizontal straight line from 1979 to early 1997, an 18 year stretch. This period of no warming was followed by the super El Nino of 1998. It carried so much warm water across the ocean that this started a step warming. In four years, global temperature rose by a third of a degree and then stopped. There has not been any warming since then and the global temperature of the twenty-first century is another horizontal straight line. There have been attempts to falsify that record by inventing an imaginary warm peak in 2005 and claiming that this and the El Nino of 2010 were higher than the super El Nino of 1998 was. This is simply a fabrication.Mean temperature is obtained by placing a dot at the the midpoint of a line connecting the peak of 2010 El Nino and the bottom of 2008 La Nina. This dot lines up perfectly with the warm plateau created by the step warming of 1998. Hansen has made a big deal of pointing out that nine out of ten warmest years happened after 2000. That is not because of any imaginary greenhouse warming but because they all sit on top that high plateau. All this means that there has been no greenhouse warming at all since the satellite era began in 1979. It also follows that the so-called “warming hiatus” extends back to the beginning of the satellite era in 1979 and was only interrupted by the super El Nino and the step warming it brought. This more than doubles the length of the presumed hiatus the author is trying to explain. But if you go back before 1997 do you then start getting greenhouse warming? Unfortunately IPCC has never specified which warming period was greenhouse warming and which one was not. They just waved their hands, pointed to the parallel rise of global dioxide and global temperature, and called that proof of anthropogenic global warming. To evaluate which warming was which we have to go through the entire twentieth century and observe the applicable laws of physics as necessary. First rule is that if you want carbon dioxide to start a sudden warming you must put carbon dioxide simultaneously in the air. That is because the absorbance of carbon dioxide in the infrared is a property of the gas and cannot be changed. Second rule is that greenhouse warming, once started, cannot be stopped suddenly. That is because once the gas molecules are mixed with air there is no way to pull them out suddenly. Starting from the beginning of the century, the first ten years were cooling. Then suddenly warming started in 1910. It kept going until 1940 and then stopped equally suddenly. It was the cold wave of World War II that stopped it, still shown as a heat wave on some temperature curves. There was no increase of carbon dioxide in 1910 which rules out greenhouse warming as a cause. And the sudden halt in 1940 likewise rules out greenhouse warming for it. By 1950 the cooling had alleviated but there was no real warming until mid-seventies. In 1976 there was a noticeable warming that was dubbed the Great Pacific Climate Shift. It was later associated with a phase shift of PDO from its cool to warm phase. It is said to have raised global temperature by 0.2 degrees although I have a problem identifying it. At any rate, it was a short step warming that was finished by 1980, which closes the cycle with the satellite era. We already determined that there was no greenhouse warming after 1979. Our survey of earlier warming has shown that there was no greenhouse warming before it either. In summary, there has not been any greenhouse warming at all for the last 100 years. This is what you must explain if you can. Hint: Miskolczi knows.

  17. mpcraig says:

    “This is why most climate scientists prefer to draw their conclusions from 30 years’ worth of data or more.”

    Santer et al(2011) is a peer reviewed study concluding that at least 17 years is needed to separate signal from noise for atmospheric temperature changes: http://onlinelibrary.wiley.com/doi/10.1029/2011JD016263/abstract

    If we look at the past 17 years, the trend is about half of that predicted by models. Regardless of whether or not Trenberth is right about an imbalance being hidden in the ocean, the models obviously aren’t accounting for it so it’s difficult to assign any confidence in them over the next few decades.

    • sully says:

      “at least 17″ doesn’t mean that 17 years of data will always give you the best, most accurate answer and you can stop right there. Santer is proposing it as a minimum for getting in the right ballpark. This is obvious unless you are seriously suggesting that 17 years of data is better than 30.

      • sully says:

        Or in other words, Santer et al are saying that’s the minimum to identify the human signal; it’s not necessarily going to give you all the signal.

        • JamesG says:

          Santer said that before he relaised that 17 years would show no warming. Now he suggests 30 because that gives him another 13 years funding.

  18. Rich Bono says:

    I have always understood the projections of temperature and ocean rise, as presented by the IPCC, as a range, not a precise prediction. So the 3 to 6 foot range, from this study still holds true…though the chances are thought to be weighted towards the lower end of the range, rather than the higher. I see none of the underlying science of anthropogenic climate change to have been overturned by his report. As it is climate change continues, and we need to learn more. We need to have better data on the effects of aerosols, and indeed water vapor as well. The risk of inciting the dangerous tipping points remains.

  19. cjorach says:

    Distinguished physicist Dr. William Happer: ‘The incredible list of supposed horrors that increasing carbon dioxide will bring the world is pure belief disguised as science’

    AGW believers needs to face up to fact they are supporting a totalitarian anti humanistic ideology for a fossil free world movement that inflicts untold misery on the poor. A Carbon free world is not a people friendly world. 20,000 Poor Ugandans thrown off land for Carbon Credits http://www.cfact.org/2013/04/24/poor-being-thrown-off-ugandan-land-for-c

    *O/T SINTEF the largest independent Swedish research org, 2,000 researchers, has a comprehensive report about the state of AGW. The report concludes with a damning verdict of the AGW theory economic policy impacts:

    “That current plans to restrict anthropogenic CO2 emissions are a dangerous
    misallocation of intellectual capital and resources that should be dedicated to solving humanity’s real and serious problems.”
    Full Report:

    Even Germany is now conceding Global Warming has stopped. http://notrickszone.com/2013/05/05/baffled-german-government-concedes-gl
    Germany has come to their senses and is kicking out the AGW scoundrels who ran their energy policies as alternative energy in Germany goes belly up.

  20. cjorach says:

    With regard to the so called “missing heat”

    mpainter says:
    May 9, 2013 at 1:23 am
    The global warmers have done it again and Dr. Pielke has called them out on it. Ocean warming at depth is merely an artifact of sampling changes. For,as he pointed out, how can heat transit from the surface to the depths without being detected in transit? Trenberth’s missing heat has become as the space alien of the old sci-fi story “Who Goes There?”


  21. The reality which David and others don’t want to accept is global warming has ended and cooling will be the reality for the rest of this current decade.

    The sun entered a prolong minimum state, which started around Oct. of 2005, and the only reasons why the temperature response has not been more downward are the following: the weak maximum of solar cycle 24 we are presently in, the OCEAN HEAT CONTENT LAG, and the accumulation of sub-solar years not being all that long, after following a period of 100+years of strong solar activity.

    As this decade proceeds these factors will be becoming less and less.

    Once the sun returns to very low solar readings, which will be the case after the solar maximum of solar cycle 24 passes by the temperature trend will be down.


    3. AP INDEX SUB 5

    All of these factors should be the rule once solar cycle 24 maximum passes by and should persist out to year 2030 or so. The result is going to be an ever increasing trend toward lower temperatures.

  22. David does not understand the GHG effect is a result of the earth/climate relationship not the cause of it.

    People like David will go down kicking and screaming but they will be going down.

    How effective the GHG effect can be depends on the amounts of energy the GHG’s have to work with to begin with which is tied to solar activity, how effective they are in being able to absorb the IR the earth emits and how close to the saturation point the various greenhouse gases are in their abilities to absorb the IR the earth emits.


    the so called lower tropospheric hot spot missing in action ,still no sign of it.


    the opposite is happening.


    not happening

    I just highlighted a few of the many false predictions the global warming models have made. There are about 30 more.


    The global warming models will never be able to make an accurate climate forecast because the proper state of the current climate can’t be put into them, the data will never be complete or accurate in all aspects to begin with, hence any feedbacks which may or may not happen will not be able to be handled in a proper manner.

    One can see that now as the projections the models have made on the temperatures going forward gets further and further off.

  23. Gerard Harbison says:

    First, I’d just like to say that this is about as lucid and well written a piece of science journalism as any I’ve read in the past few years. I do object to use of the word ‘exponential growth’ unless the growth is quite rigorously exponential. I suppose I could not be lazy and fit the Mauna Loa CO2 data to an exponential to see how well it works, but eyeballing it, it doesn’t look exponential.

    One can’t help be struck, though, by the number of points here that were raised a long time ago by climate ‘skeptics’ and were then subject to ridicule: natural oscillations, transport to the deep ocean, solar changes, urban heat islands…OK, granted, there’s a ‘broken-clock’ aspect to this, and climate skeptics have also said some incredibly stupid stuff, but still one would have wished so much of mainstream climate science hadn’t been so dismissive so quickly.

    One final point; if heat is being transferred to the deep ocean, it’s likely by mixing, and mixing also transports CO2 to the deep ocean. My relatively amateurish reading of the literature suggests that the residence time of atmospheric CO2 is one of the fuzzier quantities out there. It clearly has to be long enough to permit the observed rise in atmospheric concentration. But if it were (say) 100 years rather than 500 years, that would make a significant difference to long term modelling. Both because of its volume and because of sedimentation equilibrium, deep ocean is a huge CO2 sink, and what prevents it from damping out AGW completely is mostly the slow rate of transport down there.

    • RobertInAz says:

      “I do object to use of the word ‘exponential growth’ unless the growth is quite rigorously exponential. ”

      And the key point is the assertion that CO2 growth is exponential is used to discount the increasing likelihood documented in the peer reviewed literature that the climate sensitivity to CO2 is less, perhaps much less, than the IPCC consensus estimate.

      The evolving science is finding multiple reasons why this might be the case – ocean heat uptake is one.

  24. Bruce says:

    What I’m hearing, translated for the non-scientists, is
    “Maybe the revolver has only 4 bullets loaded instead of 5. Do you still want to play Russian Roulette?”

    • Chris says:

      “Maybe the revolver has only 4 bullets loaded instead of 5. Do you still want to play Russian Roulette?”

      Another version is
      “It’s not settled that every chamber has a bullet so just keep pulling the trigger.”

    • John Garrett says:

      What I’m hearing, translated for the non-scientists is:
      “Climatology doesn’t understand the climate system.”

      • HR says:

        I’m reading multiple explanations for the same phenomenon which translates as “we don’t know”.

        The limit being that we must only consider options that lead to conclusions that fall within the present consensus.

  25. Manfred S says:

    The ocean heat content data in above graphics are 5 years averages. If you look at the annual data, there appears to be a huge, completely implausible step upwards in the 2 years around 2003, when measurement switched to the ARGO system.


    The increase in these 2 years for the 0-2000m layer is about as large as in all other years from 1970-2010 combined !

    This is not plausible. One would expect a gradual increase in heat content, particularly smooth for the complete 0-2000m range, where layer mixing does not matter. The only plausible explanation is then that most of the increase is artificial and due to an error in splicing different data sets.

  26. HR says:


    The data you link to at NODC seems to show OHC down to 2000m to have been increasing at a near constant rate since 1970.


    I don’t see any evidence in that it lost heat in the 1990′s.

    So I don’t understand why the oceans can be blamed for the change from rapid warming in the 1970′s to 1990′s to a ‘pause’ in warming now.

  27. rafael molina navas says:

    In the long term, natural OSCILLATIONS can´t ever beat changes due to causes always acting in the same sense …
    By the way, please kindly see:
    Beeing 30 yr averages, ENSOscillations are swept away. A regular underlying warming in that monitoring place is clearly shown.

  28. Arno Arrak says:

    When you combine Arctic and Antarctic sea ice volumes you are mixing apples and oranges. There is nothing much interesting happening in the Antarctic except that the ice is being undercut in places by up-welling warm water. In the past this has led to periodic collapses of the ice sheet. According to the sedimentary record a large amount of melt water cascaded into the Ross Sea 18,000 years ago, again 10,500 years ago, again 5,500 years ago and then again 1,500 years ago. This tells us that if warm water keeps undermining the ice, as it still is, we can look forward to another such periodic collapse in a somewhat unpredictable future. The ice sheet facing the Amundsen Sea in particular is being undermined because shore winds push the cold surface water away and warmer water from below replaces it. In the Arctic the situation is entirely different. The Arctic today is the only part of the world that is still warming. That is possible only because Arctic warming is not greenhouse warming. It began at the turn of the twentieth century after 2,000 years of slow cooling, paused for 30 years in mid-century, then resumed, and is still going strong. There was no increase of atmospheric carbon dioxide when the warming started and this is what rules out the greenhouse warming as its cause. That is because the infrared absorbency of carbon dioxide is a property of the gas and cannot be changed. You must increase the number of absorbing molecules to start a warming. The start of warming was caused by a relatively rapid reorganization of North Atlantic current system that began carrying warm Gulf Stream water into the Arctic ocean. The pause in mid-century would then be explained by a temporary return of the former flow pattern of currents. Direct measurement of ocean temperature by research vessel in 2010 showed that water temperature reaching the Arctic now exceeds anything within the last 2,000 years. In addition to North Atlantic currents a lesser amount of warm water enters through the Bering Strait. It is usually enough to clear the Chuckchi Sea of ice in the summer. But in 2007 pole-ward winds brought so much warm water through that it melted a large patch of open water to its north. The Russian side was unaffected. And what about the future? The warming continues, but nature is fickle and what has happened before can happen again. What if the warming pause of mid-twentieth century should repeat itself? Someone ought to study this to avoid being blindsided by nature.

  29. Excellent article on Global Warming.
    Dr.A.Jagadeesh Nellore(AP),India