From UC Berkeley Earth comes this paper that tries some new statistical techniques to get “the pause” to go away, following on with the infamous Karl et al paper of 2015, that played tricks with SST measurements done in the 40’s and 50’s to increase the slope of the warming. This aims to do the same, though the methods look to be a bit more sophisticated than Karl’s ham-handed approach. The paper link is below, fully open sourced. I invite readers to have a look at it, and judge for yourselves. Personally, it looks like ignoring the most current data available for 2016, which has been cooling compared to 2015, invalidates the claim right out of the gate.
If a climate skeptic did this sort of stuff, using incomplete data, we’d be excoriated. yet somehow, this paper using incomplete data gets a pass by the journal, and publishes with 2015 data at the peak of warming, just as complete 2016 data becomes available.
The results section of the paper say:
From January 1997 through December 2015, ERSSTv3b has the lowest central trend estimate of the operational versions of the four composite SST series assessed, at 0.07°C per decade. HadSST3 is modestly higher at 0.09°C per decade, COBE-SST is at 0.08°C per decade, whereas ERSSTv4 shows a trend of 0.12°C per decade over the region of common coverage for all four series. We find that ERSSTv3b shows significantly less warming than the buoy-only record and satellite-based IHSSTs over the periods of overlap [P < 0.01, using an ARMA(1, 1) (autoregressive moving average) model to correct for autocorrelation], as shown in Fig. 1. ERSSTv3b is comparable to ERSSTv4 and the buoy and satellite records before 2003, but notable divergences are apparent thereafter.
What’s missing? Error bars showing uncertainty. Plus, the data only goes to December 2015. They’ve missed an ENTIRE YEAR’s worth of data, and while doing so claim “the pause” is busted. It would be interesting to see that same graph done with current data through December 2016, where global SST has plummeted. Looks like a clear case of cherry picking to me, by not using all the available data. Look for a follow up post using all the data.
Here’s what the world’s sea surface temperature looks like at the end of 2016 – rather cool.
Compare that to December 2015, for Hausfather’s end data period – they ended on a hot note:
I did ask Zeke Hausfather, the lead author about this paper via email, about it and the data, and to his credit, he responded within the hour, saying:
We haven’t updated our buoy-only, satellite-only, and argo-only records to present yet (then still end January 1st 2016), but we are planning on updating them in the near future.By the way, the paper itself is open access, available here: http://advances.sciencemag.org/content/3/1/e1601207.full.pdf+htmlWe also have a background document we put together here: http://www-users.york.ac.uk/~kdc3/papers/ihsst2016/background.htmlI’m attaching the data shown in that figure. All series have been masked to common coverage (though we we do three different variations of tests for coverage effects, as we discuss in detail in the paper).The data are:acci97Mm.temp – Satellite radiometer record from 1997 (from ATSR and AVHRR)buoy97Mm.temp – Buoy-only record from 1997cobe97Mm.temp – COBE-SST (Japanese record)had97Mm.temp – HadSST3v3_97Mm.temp – ERSSTv3bv4_97Mm.temp – ERSSTv4We start in 1997 because prior to that there is insufficient data from buoys to get a global estimate, and satellite data is only available from mid-1996.Hope that helps,-Zeke
I have made the data available here in a ZIP file (17KB)
That’s how science should work, sharing the data, but I contend that the data should be updated in the paper before publishing it. A year long gap, with a significant cooling taking place, is bound to change the results. Perhaps this is an artifact of the slow peer-review process.
But, Zeke should know better, than to allow the word “disproved” in a headline. We’ll see how well his study claims of “pause-busting” hold up in a year without a major El Niño to bolster his case.
UPDATE: Bob Tisdale points out via email that this paper seems to be a manifestation of a guest post at Judith Curry’s a year ago:
In that post, there’s some serious concerns about the buoy data used, from climate Scientist John Kennedy of the UK Met Office
A controversial paper published two years ago that concluded there was no detectable slowdown in ocean warming over the previous 15 years — widely known as the “global warming hiatus” — has now been confirmed using independent data in research led by researchers from UC Berkeley and Berkeley Earth, a non-profit research institute focused on climate change.
After correcting for this “cold bias,” researchers with the National Oceanic and Atmospheric Administration concluded in the journal Science that the oceans have actually warmed 0.12 degrees Celsius (0.22 degrees Fahrenheit) per decade since 2000, nearly twice as fast as earlier estimates of 0.07 degrees Celsius per decade. This brought the rate of ocean temperature rise in line with estimates for the previous 30 years, between 1970 and 1999.The 2015 analysis showed that the modern buoys now used to measure ocean temperatures tend to report slightly cooler temperatures than older ship-based systems, even when measuring the same part of the ocean at the same time. As buoy measurements have replaced ship measurements, this had hidden some of the real-world warming.
This eliminated much of the global warming hiatus, an apparent slowdown in rising surface temperatures between 1998 and 2012. Many scientists, including the International Panel on Climate Change, acknowledged the puzzling hiatus, while those dubious about global warming pointed to it as evidence that climate change is a hoax.
Climate change skeptics attacked the NOAA researchers and a House of Representatives committee subpoenaed the scientists’ emails. NOAA agreed to provide data and respond to any scientific questions but refused to comply with the subpoena, a decision supported by scientists who feared the “chilling effect” of political inquisitions.
The new study, which uses independent data from satellites and robotic floats as well as buoys, concludes that the NOAA results were correct. The paper will be published Jan. 4 in the online, open-access journal Science Advances.
“Our results mean that essentially NOAA got it right, that they were not cooking the books,” said lead author Zeke Hausfather, a graduate student in UC Berkeley’s Energy and Resources Group.
Long-term climate records
Hausfather said that years ago, mariners measured the ocean temperature by scooping up a bucket of water from the ocean and sticking a thermometer in it. In the 1950s, however, ships began to automatically measure water piped through the engine room, which typically is warm. Nowadays, buoys cover much of the ocean and that data is beginning to supplant ship data. But the buoys report slightly cooler temperatures because they measure water directly from the ocean instead of after a trip through a warm engine room.
Hausfather and colleague Kevin Cowtan of the University of York in the UK extended that study to include the newer satellite and Argo float data in addition to the buoy data.NOAA is one of three organizations that keep historical records of ocean temperatures – some going back to the 1850s – widely used by climate modelers. The agency’s paper was an attempt to accurately combine the old ship measurements and the newer buoy data.
“Only a small fraction of the ocean measurement data is being used by climate monitoring groups, and they are trying to smush together data from different instruments, which leads to a lot of judgment calls about how you weight one versus the other, and how you adjust for the transition from one to another,” Hausfather said. “So we said, ‘What if we create a temperature record just from the buoys, or just from the satellites, or just from the Argo floats, so there is no mixing and matching of instruments?’”
In each case, using data from only one instrument type – either satellites, buoys or Argo floats – the results matched those of the NOAA group, supporting the case that the oceans warmed 0.12 degrees Celsius per decade over the past two decades, nearly twice the previous estimate. In other words, the upward trend seen in the last half of the 20th century continued through the first 15 years of the 21st: there was no hiatus.
“In the grand scheme of things, the main implication of our study is on the hiatus, which many people have focused on, claiming that global warming has slowed greatly or even stopped,” Hausfather said. “Based on our analysis, a good portion of that apparent slowdown in warming was due to biases in the ship records.”
Correcting other biases in ship records
In the same publication last year, NOAA scientists also accounted for changing shipping routes and measurement techniques. Their correction – giving greater weight to buoy measurements than to ship measurements in warming calculations – is also valid, Hausfather said, and a good way to correct for this second bias, short of throwing out the ship data altogether and relying only on buoys.
“In the last seven years or so, you have buoys warming faster than ships are, independently of the ship offset, which produces a significant cool bias in the Hadley record,” Hausfather said. The new study, he said, argues that the Hadley center should introduce another correction to its data.
“People don’t get much credit for doing studies that replicate or independently validate other people’s work. But, particularly when things become so political, we feel it is really important to show that, if you look at all these other records, it seems these researchers did a good job with their corrections,” Hausfather said.
Co-author Mark Richardson of NASA‘s Jet Propulsion Laboratory and the California Institute of Technology in Pasadena added, “Satellites and automated floats are completely independent witnesses of recent ocean warming, and their testimony matches the NOAA results. It looks like the NOAA researchers were right all along.“
Other co-authors of the paper are David C. Clarke, an independent researcher from Montreal, Canada, Peter Jacobs of George Mason University in Fairfax, Virginia, and Robert Rohde of Berkeley Earth. The research was funded by Berkeley Earth.
The paper: Assessing Recent Warming Using Instrumentally-Homogeneous Sea Surface Temperature Records (Science Advances)