New government study purports to show no hiatus in global warming

A new study, published in the peer-reviewed journal Science, makes the claim that the lack of warming since the beginning of this century, as acknowledged by the U.N.'s Intergovernmental Panel on Climate Change (IPCC) last December, is actually a statistical mirage. 

The National Oceanic and Atmospheric Administration (NOAA), along with an independent government consulting company, try to make the case that the temperatures gathered from around the world to prove the lack of warming are wrong and that "adjustments" must be made in order to get a true representation of the data.

New York Times:

When adjustments are made to compensate for recently discovered problems in the way global temperatures were measured, the slowdown largely disappears, the National Oceanic and Atmospheric Administration declared in a scientific paper published Thursday. And when the particularly warm temperatures of 2013 and 2014 are averaged in, the slowdown goes away entirely, the agency said.

“The notion that there was a slowdown in global warming, or a hiatus, was based on the best information we had available at the time,” said Thomas R. Karl, director of the National Centers for Environmental Information, a NOAA unit in Asheville, N.C. “Science is always working to improve.”

The change prompted accusations on Thursday from some climate-change denialists that the agency was trying to wave a magic wand and make inconvenient data go away. Mainstream climate scientists not involved in the NOAA research rejected that charge, saying it was essential that agencies like NOAA try to deal with known problems in their data records.

At the same time, senior climate scientists at other agencies were in no hurry to embrace NOAA’s specific adjustments. Several of them said it would take months of discussion in the scientific community to understand the data corrections and come to a consensus about whether to adopt them broadly.

“What you have is a reasonable effort to deal with known biases, and obviously there is some uncertainty in how you do that,” said Gavin A. Schmidt, who heads a NASA climate research unit in New York that deals with similar issues.

Some experts also pointed out that, depending on exactly how the calculation is done, a recent slowdown in global warming still appears in the NOAA temperature record, though it may be smaller than before. “These trends are very sensitive to the time periods you use to compute them,” said Gerald A. Meehl, a senior scientist at the National Center for Atmospheric Research in Boulder, Colo.

Scientists like Dr. Meehl never accepted the notion, put forward by some climate contrarians, that the slowdown disproved the idea that global warming poses long-term risks. But they said they believe it is real and demands an explanation.

A leading hypothesis to explain the slowdown is that natural fluctuations in the Pacific Ocean may have temporarily pulled some heat out of the atmosphere, producing a brief flattening in the long-term increase of surface temperatures.

It's good that even some climate change advocates are questioning the study, but what of the skeptical community – the "denialists," as the NY Times inaccurately portrays them? 

Anthony Watts's page, always the go-to site for rational analysis of hysterical claims by global warming advocates, has several essays on the new paper by NOAA, taking apart the data piece by piece.  This essay by three skeptics, including MIT's Richard Lindzen, bears reading:

The main claim by the authors that they have uncovered a significant recent warming trend is dubious. The significance level they report on their findings (.10) is hardly normative, and the use of it should prompt members of the scientific community to question the reasoning behind the use of such a lax standard.

In addition, the authors’ treatment of buoy sea-surface temperature (SST) data was guaranteed to create a warming trend. The data were adjusted upward by 0.12°C to make them “homogeneous” with the longer-running temperature records taken from engine intake channels in marine vessels.

As has been acknowledged by numerous scientists, the engine intake data are clearly contaminated by heat conduction from the structure, and as such, never intended for scientific use. On the other hand, environmental monitoring is the specific purpose of the buoys. Adjusting good data upward to match bad data seems questionable, and the fact that the buoy network becomes increasingly dense in the last two decades means that this adjustment must put a warming trend in the data.

The extension of high-latitude arctic land data over the Arctic Ocean is also questionable.   Much of the Arctic Ocean is ice-covered even in high summer, meaning the surface temperature must remain near freezing. Extending land data out into the ocean will obviously induce substantially exaggerated temperatures.

Additionally, there exist multiple measures of bulk lower atmosphere temperature independent from surface measurements which indicate the existence of a “hiatus”. If the Karl et al., result were in fact robust, it could only mean that the disparity between surface and midtropospheric temperatures is even larger that previously noted.

Getting the vertical distribution of temperature wrong invalidates virtually every forecast of sensible weather made by a climate model, as much of that weather (including rainfall) is determined in large part by the vertical structure of the atmosphere.

Instead, it would seem more logical to seriously question the Karl et al. result in light of the fact that, compared to those bulk temperatures, it is an outlier, showing a recent warming trend that is not in line with these other global records.

A polite way of saying "you're full of crap."

Judith Curry, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, was also polite but perhaps even more critical:

My bottom line assessment is this. I think that uncertainties in global surface temperature anomalies [are] 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 few random observations:

1. Even the authors of the study don't have a lot of confidence in its conclusions.  They titled their paper "Possible artifacts of data biases in the recent global surface warming hiatus."

2. Note the careful, substantative critique of the paper by skeptics compared to the name-calling and personal attacks by climate change hysterics whenever their research is challenged.

3. I find it fascinating that when skeptics question conclusions by the IPCC, they are branded anti-science.  Now pro-global warmists are challenging the IPCC's own conclusions about the pause in warming.  Will they also be branded "anti-science"?

4. How much of a political document is the NOAA study, and how much is related to real science?  The "data biases" mentioned are acknowledged by both advocates and skeptics.  It appears that the NOAA paper looks to explain the biases in the best possible light to advance the theory of catastrophic climate change – fudging the numbers.  But is their technique scientifically legitimate?  There will be the challenge to the paper's conclusions.

Another strange coincidence is that the paper has been published in the midst of President Obama's major push to issue carbon regulations.  I'm sure it's just an accident of timing and has nothing to do with the politics of advancing the global warming agenda.

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