Climate alarmists are all atwitter over a new paper from researchers at NOAA/NCDC. In that paper the claim is made that the 18+ year pause in global warming is not real and that temperatures have been going up as expected. After more than a decade agonizing over the cause for the pause, desperately searching for the “missing” heat, dogmatic climate scientists have given up and simply declared the whole “hiatus” an accounting error. The temperature record in question is a kludged up global yearly average based on a hodgepodge of reporting stations, some on land and others at sea. In performing a “reanalysis” of the temperature record it was “discovered” that changes in the way temperatures were measured, particularly at sea, were systematically wrong, and “correcting” these readings causes the whole pesky pause thing to go away. What isn't mentioned are the other datasets that clearly show the pause is real, including two different satellite records. Has the climate catastrophe cabal given up all pretense of doing real science and decided to manipulate the data to give the answer they want? Many think so.
There has been no more troubling phenomenon for climate scientists than the 18+ year dramatic slowing in the rate of global temperature increase. As many as sixty different explanations have been offered in journal articles, an indication of how flummoxed the climate change community has been. Whether you call it the pause, the hiatus, or the slowdown, every major climate research organization has admitted it is real. The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded that the global surface temperature “has shown a much smaller increasing linear trend over the past 15 years [1998-2012] than over the past 30 to 60 years.”
Similarly, the UK's Met Office was proclaiming the pause as recently as June 5th, 2015. “The world stopped getting warmer almost 16 years ago, according to new data released last week,” reported the Daily Mail, referring to data collected on global temperature known as Hadcrut 4, issued by the Met Office’s Hadley Centre. “The figures, which have triggered debate among climate scientists, reveal that from the beginning of 1997 until August 2012, there was no discernible rise in aggregate global temperatures. This means that the ‘plateau’ or ‘pause’ in global warming has now lasted for about the same time as the previous period when temperatures rose, 1980 to 1996. Before that, temperatures had been stable or declining for about 40 years.”
Some, like NASA's Gavin Schmidt, are on record saying the pause won't last. Predicting that the “hiatus” would be over within a decade, Schmidt said, "in five to ten years time it is changes in greenhouse gases that will dominate." The obvious question is, how can something end in five to ten years if it isn't real in the first place? Of course, the existence of the pause is an example of that scientific consensus that climate change boosters are always on about.
Now Thomas Karl, director of the National Oceanic and Atmospheric Administration's National Climatic Data Center, and colleagues have published a paper in the journal Science that basically says it was all a mistake, this pause thing was caused by bad data. In “Possible artifacts of data biases in the recent global surface warming hiatus,” Karl et al say that the pause just was not real, blaming the whole affair on flawed but well meaning scientists who just didn't pay enough attention while collecting surface temperature data. Here is the authors' explanation of the paper's purpose:
The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded that the global surface temperature “has shown a much smaller increasing linear trend over the past 15 years [1998-2012] than over the past 30 to 60 years.” The more recent trend was “estimated to be around one-third to one-half of the trend over 1951-2012.” The apparent slowdown was termed a “hiatus,” and inspired a suite of physical explanations for its cause, including changes in radiative forcing, deep ocean heat uptake, and atmospheric circulation changes. While these analyses and theories have considerable merit in helping to understand the global climate system, other important aspects of the “hiatus” related to observational biases in global surface temperature data have not received similar attention. In particular, residual data biases in the modern era could well have muted recent warming, and as stated by IPCC, the trend period itself was short and commenced with a strong El Niño in 1998. Given recent improvements in the observed record and additional years of global data (including a record-warm 2014), we re-examine the observational evidence related to a “hiatus” in recent global surface warming.
Notice how they even throw in the 1998 El Niño and the shortness of the pause as mitigating factors, though why such information should be meaningful if the pause was not real in the first place is curious. The bottom line on their correction of existing temperature data comes down to rejiggering buoy- and ship-based data. After much manipulation of the data they present their “new” analysis in the figure shown below (Fig 1 from the paper).
Temperature trends are shown for data with the “new” analysis (squares) and “old” analysis (circles) for several periods of interest. Also indicated are global values calculated with the new corrections and the polar interpolation method (triangles). The error bars represent the 90% confidence intervals. The additional error associated with uncertainty of our corrections extends the 90% CI and is depicted with a horizontal dash. (A) and (B) show the base period (1951–2012) and “hiatus” period used in IPCC (1). (C) An alternate base period—the second half of the 20th century. (D) The 21st century through 2014. (E) 1998 (a strong El Niño year) through the 21st century. Here is how they summed up their findings:
In summary, newly corrected and updated global surface temperature data from NOAA’s NCEI do not support the notion of a global warming “hiatus.” As shown in Fig. 1, there is no discernable (statistical or otherwise) decrease in the rate of warming between the second half of the 20th century and the first 15 years of the 21st century. Our new analysis now shows the trend over the period 1950-1999, a time widely agreed as having significant anthropogenic global warming, is 0.113°C dec−1, which is virtually indistinguishable with the trend over the period 2000-2014 (0.116°C dec−1). Even starting a trend calculation with 1998, the extremely warm El Niño year that is often used as the beginning of the “hiatus”, our global temperature trend (1998-2014) is 0.106°C dec−1 – and we know that is an underestimate due to incomplete coverage over the Arctic. Indeed, based on our new analysis, the IPCC’s statement of two years ago – that the global surface temperature “has shown a much smaller increasing linear trend over the past 15 years than over the past 30 to 60 years” – is no longer valid.
Got that? There was no pause, it was just a mass hallucination by the entire climate science community. How could all those scientists have gotten the recent temperature record so wrong? Supposedly the instruments and methodologies used most recently are the most accurate, but it is the recent record that gets a big adjustment. I guess this shows what a crock of hooey consensus is. Either that, or this paper is just an example of the old saying among researchers, “when all else fails, manipulate the data.” So which is it, epic fail for climate science or a load of bollocks? Let's look a bit closer.
Not everyone agrees that the pause is entirely a data artifact, even among died in the wool alarmists. Michael Mann, of Pennsylvania State University, a prominant global warming agitator, notes that there is “very clear” evidence of a slowdown in large-scale warming in the tropical Pacific. In a previous paper, “Atlantic and Pacific multidecadal oscillations and Northern Hemisphere temperatures,” he and others linked it to a natural decades-long climate pattern that brought about La Niña–like cooler conditions in the past decade. “The tropical Pacific definitely warmed less over that time period than climate models had predicted,” says Mann, who prefers the term “temporary slowdown.”
Others, Like Judith Curry, Professor and former Chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, are less tentative. “Color me ‘unconvinced.’” she says on her blog. Dr. Curry goes on to say:
The greatest changes in the new NOAA surface temperature analysis is to the ocean temperatures since 1998. This seems rather ironic, since this is the period where there is the greatest coverage of data with the highest quality of measurements – ARGO buoys and satellites don’t show a warming trend. Nevertheless, the NOAA team finds a substantial increase in the ocean surface temperature anomaly trend since 1998.
In my opinion, the gold standard dataset for global ocean surface temperatures is the UK dataset, HadSST3. A review of the uncertainties is given in this paper by John Kennedy http://www.metoffice.gov.uk/hadobs/hadsst3/uncertainty.html. Note, the UK group has dealt with the same issues raised by the NOAA team. I personally see no reason to the use the NOAA ERSST dataset, I do not see any evidence that the NOAA group has done anywhere near as careful a job as the UK group in processing the ocean temperatures.
Curry also takes the time to criticize the method used to “fill the gaps” in surface data coverage in the NOAA methodology. I have touched on this previously, pointing out that large tracts of Earth's surface are filled in with readings from only a few recording stations. “I am also unconvinced by NOAA’s gap filling in the Arctic, and in my opinion this introduces substantial error into their analysis,” she states.
Ross McKitrick, of the University of Guelph, posted a preliminary analysis online. After pointing out that all the other recognized temperature datasets disagree with Karl et al's new result. Most prominent are the discrepancies between the new result and the two satellite temperature records, known as the RSS and UAH. These records, taken by measuring Infra Red (IR) radiation from the lower troposphere, were considered a great advance during the 1980's and 90's when they showed warming. Since then, they have clearly shown the pause in global temperature rise, falling out of favor with those who bang the drum of climate disaster. The figure below shows the RSS record for the 2004-2014.
Plots of the major global temperature datasets are shown in McKitrick's article. It is clear that the observed global-mean surface temperature (GMST) has shown a much smaller increasing trend over the past 15 years than over the past 30 to 60 years. Indeed, depending on the dataset, the GMST trend over 1998–2012 is estimated to be around one-third to one-half of the trend over 1951–2012. The conclusions of McKitrick's analysis are as follows (the Karl paper is referred to as K15):
A great deal of work has been done in recent decades both to try and recover some of the metadata for in situ temperature readings, and also to estimate corrections in order to overcome biases that affect the raw data. K15 have made some relatively minor changes to the bias correction methods, and the result is a large increase in the post-1998 trend.
A. They added 0.12°C to readings collected by buoys, ostensibly to make them comparable to readings collected by ships. As the authors note, buoy readings represent a rising fraction of observations over recent decades, so this boosts the apparent warming trend.
B. They also gave buoy data extra weight in the computations.
C. They also made adjustments to post-1941 data collected from ships, in particular a large cooling adjustment applied to readings over 1998-2000.
Taken together these changes largely explain the enhanced trend over the past 15 years. So now everybody needs to decide if they think these adjustments are valid.
In a similar vein, the Global Warming Policy Forum has published its own critique of the Karl paper. They call it “not up to the standards of a comprehensive paper,” and “a highly speculative and slight paper that produces a statistically marginal result by cherry-picking time intervals, resulting in a global temperature graph that is at odds with all other surface temperature datasets, as well as those compiled via satellite.” Here is the GWPF's list of key pitfalls in the Karl paper:
- The authors have produced adjustments that are at odds with all other surface temperature datasets, as well as those compiled via satellite.
- They do not include any data from the Argo array that is the world’s best coherent data set on ocean temperatures.
- Adjustments are largely to sea surface temperatures (SST) and appear to align ship measurements of SST with night marine air temperature (NMAT) estimates, which have their own data bias problems.
- The extend of the largest SST adjustment made over the hiatus period, supposedly to reflect a continuing change in ship observations (from buckets to engine intake thermometers) is not justified by any evidence as to the magnitude of the appropriate adjustment, which appears to be far smaller.
It will be interesting to see how the climate change community responds to the Karl paper—will they rush to embrace this “solution” to the vexing pause, or will they try to retain some semblance of scientific credibility? S. Fred Singer, professor emeritus at the University of Virginia and a founding director of the Science & Environmental Policy Project, thinks that a monumental food fight is brewing among climate scientists.
Oh boy! Get ready to watch yet another big fight about climate change – this time mainly among different groups of climate alarmists. Is there a “pause”? Did global climate really stop warming during the last dozen years, 18 years, or even 40 years – in spite of rising levels of the greenhouse (GH) gas carbon dioxide? …
There are at least two rival data centers that may dispute the NCDC analysis: the Hadley Centre in England and the NASA-Goddard Institute for Space Studies (GISS). In fact, Hadley’s partner, the Climate Research Unit at the University of East Anglia, was the first to announce, on the BBC, the existence of a pause in global warming.
The paper does effectively dismiss legions of other climate researchers who have published research papers, attempting to provide an explanation for the reported pause. Singer also noted: “It does look a little suspicious that NCDC arrived at this earth-shaking “discovery” after all these years, after “massaging” its own weather-station data, just before the big policy conference in December in Paris that is supposed to slow the rise of CO2 from the burning of energy fuels, coal, oil, and gas.”
Evidently the debate isn't over even among climate scientists.
Regardless, it is certainly headline bait, being picked up across the internet. But will it withstand scientific scrutiny? Here, again, are the words of Judith Curry, stating her assessment of the paper's veracity.
My bottom line assessment is this. I think that uncertainties in global surface temperature anomalies is substantially understated. The surface temperature data sets that I have confidence in are the UK group and also Berkeley Earth. This short paper in Science is not adequate to explain and explore the very large changes that have been made to the NOAA data set. The global surface temperature datasets are clearly a moving target. So while I’m sure this latest analysis from NOAA will be regarded as politically useful for the Obama administration, I don’t regard it as a particularly useful contribution to our scientific understanding of what is going on.
A politically useful paper, not a scientifically significant one. That Science is biased in favor of global warming dogma is no secret in scientific circles, their support often verging on activism. There was a big push to promote this paper by the American Association for the advancement of Science (AAAS), the publishers of Science. They even sent out a preanouncment to press contacts days in advance. It is truly a sad day for science when a once respectable journal gives a pass to highly suspect data manipulation just to garner publicity.According to Karl et al the pause was not, is not, real. It is only an artifact of decades of crappy temperature data, the same data that has fed the grossly inaccurate climate models that are at the heart of the global warming scam. And that's the real bottom line—for this paper to be correct all the historical data, all the work of climate scientists around the world over the past 40-50 years, has been in error. If this paper is correct climate science has lost all credibility.
Be safe, enjoy the interglacial and stay skeptical.