Fact-Checking the Latest Climate ‘Scandal’
In an article in the UK’s Daily Mail on Sunday, David Rose makes the extraordinary claim that “world leaders were duped into investing billions over manipulated global warming data”, accusing the U.S. National Oceanic and Atmospheric Administration (NOAA) of manipulating the data to show more warming in a 2015 study by Tom Karl and coauthors.
What he fails to mention is that the new NOAA results have been validated by independent data from satellites, buoys and Argo floats and that many other independent groups, including Berkeley Earth and the UK’s Met Office Hadley Centre, get effectively the same results.
The new NOAA record published by Karl and his colleagues primarily updated their ocean temperature record. While they also released a revised land record based on data from the International Surface Temperature Initiative (and the related Global Historical Climatology Network version 4 beta product – GHCNv4), the land record was largely similar to their prior record and was responsible for relatively little of the increase in warming they showed.
I recently led a team of researchers that evaluated NOAA’s updates to their ocean temperature record. In a paper published last month in the journal Science Advances, we compared the old NOAA record and the new NOAA record to independent instrumentally homogenous records created from buoys, satellite radiometers, and Argo floats. Our results, as you can see in the chart below, show that the new NOAA record agrees quite well with all of these, while the old NOAA record shows much less warming.
This was due to two factors: The old NOAA record spliced together warmer ship data with colder buoy data without accounting for the offset between the two; and the new NOAA record puts more weight on higher-quality buoy records and less weight on ship records (versus the old NOAA record which treated ships and buoys equally). You can read more about the study in Carbon Brief’s article.
The fact that the new NOAA record is effectively identical with records constructed only from higher quality instruments (buoys, satellite radiometers, and Argo floats) strongly suggests that NOAA got it right and that we have been underestimating ocean warming in recent years.
John Kennedy, a researcher at the UK’s Met Office in charge of their ocean temperature product, agrees that NOAA’s new record is probably the most accurate in the last two decades, remarking: “At a global scale, those adjustments really do seem to work and the ERSSTv4 adjustments [NOAA’s new record] work best of all.”
Rose’s claim that NOAA’s results “can never be verified” is patently incorrect, as we just published a paper independently verifying the most important part of NOAA’s results.
The land record that NOAA used in the Karl et al paper was a sneak peek at their new GHCNv4, which increases the number of global land stations from the 4,400 currently used to around 25,000.
This is quite similar to the Berkeley Earth land temperature record, which uses a similar number of stations. There is little reason to think that the inclusion of more station data will give us less accurate results.
The Karl et al land record ends up quite similar to the old one, though it shows about 5 percent more warming since 1970, mostly attributable to the inclusion of additional stations in the Arctic. As the chart below demonstrates, their results are quite similar to those of Berkeley Earth as well as the current operational NOAA land record (based on GHCN version 3), and also agree quite well with the latest version of GHCNv4.
The new NOAA temperature record is also by no means an outlier when compared to other groups producing global (land and ocean) surface temperature records. It shows less warming in recent years than records from Berkeley Earth, NASA, and Cowtan and Way, and a bit more warming than found in the Hadley Centre/CRU record. The old NOAA record, on the other hand, was on the bottom of the pack, with less warming than found by the other groups.
If folks don’t like the NOAA data, they will get the exact same story using surface temperature data from any other group, with no detectable sign of a “hiatus” or “pause” through to the present.
In his article, David Rose relies on reports from a researcher at NOAA who was unhappy about the data archiving associated with the Karl et al paper. While I cannot speak to how well the authors followed internal protocols, they did release their temperature anomalies, spatially gridded data land and ocean data, and the land station data associated with their analysis. They put all of this up on NOAA’s FTP site in early June 2015, at the time that the Karl et al paper was published.
As someone who works on and develops surface temperature records, the data they provided would be sufficient for me to examine their analysis in detail and see how it compared to other groups. In fact, I used the data they provided shortly after the paper was published to do just that. While it would have been nice for them to publish their full analysis code online as well as the data, I’m sure they would have provided it to any researchers who asked.
Rose also makes a big deal about the fact that NOAA’s new ocean temperature product adjusts buoys up to match ship data versus adjusting ship data down to match buoys. This turns out to be a bit of a red herring; since scientists are interested in the change in temperatures over time, you end up with the same increase in temperatures (e.g, the temperature trend) if you apply the offset to one or the other.
Because climate scientists work with temperature anomalies (rather than absolutes), the direction of the offset doesn’t have any effect on the resulting temperature series. On the other hand, not correcting for the offset between ships and buoys results in a spurious cooling bias, and a record that differs a lot from the buoys themselves as we found in our paper.
Rose’s article presents a deeply misleading graph where he shows an arbitrary offset between NOAA’s data and the Hadley land/ocean dataset. This is an artefact of the use of different baselines; Hadley’s “0C” value is relative to the average temperature from 1961-1990, while NOAA’s is relative to the average temperature from 1901-2000 (a period which includes the colder early 20th century).
This comparison ends up being spurious, because each record uses a different baseline period to define their temperature anomaly. As the chart below shows, when you correctly put the two datasets on the same baseline (eg, with respect to the 1961-1990 period), you find no offset in recent years between the two, though there is slightly more warming in the NOAA dataset due to the higher weight they give more reliable buoy data in their analysis.
Similarly, if you simply download the NOAA and Hadley ocean temperature datasets you would find that the published Hadley values are actually higher than the published NOAA ocean values in recent years. This is because Hadley uses a 1961-1990 baseline for their ocean temperature product while NOAA uses a 1971-2000 baseline. Putting both datasets on a common baseline is essential to performing accurate comparisons.
NOAA is planning on further updates to their sea surface temperature record this year to incorporate Argo data and to make some adjustments to their spatial interpolation technique. Based on the preliminary results that their team presented at the American Geophysical Union meeting late last year, their new record (ERSSTv5) will have about 10% less warming than their current record (ERSSTv4) over the 2000-2015 period, largely due to changes in the way that they account for areas with limited data. Their upcoming record will still show 50% more warming than the old NOAA record (ERSSTv3b).
While NOAA’s data management procedures may well need improvement, their results have been independently validated and agree with separate global temperature records created by other groups.
The “astonishing evidence” that David Rose purports to reveal in no way changes our understanding of modern warming or our best estimates of recent rates of warming. It does not in any way change the evidence that policymakers have at their disposal when deciding how to address the threats posed by climate change.
If anything, there is strong independent evidence that NOAA’s new record may be the most accurate one over the last two decades, at least for the two-thirds of the world covered in ocean.
Zeke Hausfather is a climate scientist and energy systems analyst at Berkeley Earth, an independent temperature analysis project.
It seems that data reliability is a priority at NOAA but remains a moving target. They admit some still unaccounted potential biases – https://www.ncdc.noaa.gov/monitoring-references/faq/temperature-monitoring.php. For instance :
“The increase in buoy observations and decrease in ship observations may require a different bias adjustment. Further study is needed to completely remove this effect from the data.”
One gets the sense that the raw data and normalization methods are always improving and perhaps those continuing studies of potential or poorly understood bias will reveal only small normalization adjustments when finally nailed down. As a non-scientist – at least in the professional sense – I remain interested in the debate and any good analysis of scientific work products.
As far as the link (http://ow.ly/CouZ309dDYV) shared above by Tom Harris I did not dig into this other than read the linked article. Sounds like there is some concern but the actual letter seems only to cast aspersion by implication that NOAA has cooked data similar to the EPA. It’s not clear where their evidence is of this accusation.
Note that this Undark discussion and the NOAA GHCN data processes are just addressing data collection and refinement. The research and debate on anthropomorphic contributions to global warming or climate change is another ball of yarn to be unraveled.
I remain a healthy skeptic. Throughout history there have too many instances of scientific certainty eventually being shown wrong. (E.g. Flat earth) in addition, it does seem the vast majority of research is funded by groups or governments with a pre-disposition and certainly the science has become mixed with politics. I would ask why, today, some highly regarded scientists in this field remain skeptics or even ardantly reject man-made climate change?
What do you think of this: https://wattsupwiththat.com/2016/01/28/300-scientists-tell-chairman-of-the-house-science-committee-we-want-noaa-adhere-to-law-of-the-data-quality-act/