“BEST” Researchers’ efforts aim to improve data on surface temperature estimates and their use could bolster public’s understanding of global land temperatures. It’s no surprise that the effort is not without some controversy.
BERKELEY, Ca. — The Berkeley Earth Surface Temperature (BEST) project is a recent effort on the part of a number of senior scientists and academics to improve surface temperature estimates by increasing the amount of data available and refining methods used to analyze that data.
The project itself has attracted some criticisms, particularly for reaching out to skeptics to try and address their concerns. But the methods the team is using are fundamentally sound, and the results, while unlikely to differ much at a global level from existing temperature records, can provide a good resource for improving regional temperature assessment and analyzing issues like the urban heat island effect. Those steps in turn can help improve public understanding of and communications on global land temperatures.
One of the unfortunate legacies of the hacked e-mail controversies over the past 16 months is a growing distrust of surface temperature records among some segments of the public. A Fox News executive was even moved to send out a memo to staff asking them to “refrain from asserting that the planet has warmed … without immediately pointing out that such theories are based upon data that critics have called into question.”
The heightened skepticism has given rise to a number of efforts among scientists and bloggers to bolster the methods and data used to create global temperature records.
The Berkeley project, undertaken by Richard Muller and his team, had a similar impetus. The team includes a rather distinguished list of scientific luminaries, including the statistician David Brillinger, and physicists Saul Perlmutter, Robert Jacobsen, and Arthur Rosenfeld. Climate scientist Judith Curry of Georgia Tech is advising the team, and Robert Rohde is the lead scientist on the project.
Based on very early and still-un-peer-reviewed sampling of just 2 percent of some 1.6 billion records, Pace University writer and blogger Andrew C. Revkin has written, Muller’s recent statements before a House committee “surely can’t be welcome to lawmakers hoping to undercut the credibility of climate science.” Revkin’s posting and comments on it include many useful links for those wanting to further explore the BEST situation. Playing-off Al Gore’s “Inconvenient Truth” title, the Revkin posting was headlined “Republicans Get Inconvenient Replies at Climate Hearing.”
Liberal economics columnist Paul Krugman also weighed-in on the Muller testimony before the House committee, echoing views expressed in Revkin’s blog posting and writing in an April 4 op-ed column that Muller had reported that his group’s preliminary results find a global warming trend “very similar to that reported by the prior groups.”
More Station Data, and New Approaches
The BEST scientists and academics have incorporated additional station data, developed their own approach to combine short records, and developed a spatial interpolation method as an alternative to traditional gridding. They have also applied a particularly innovative approach to allowing them to better deal with various problems like station moves, time of observation changes, and instrument changes that plague the temperature record.
Their major innovation is to treat problems in station records as the start of a separate record. These problem areas are detected by comparing individual stations to their surrounding stations and looking for break points or discontinuities in a station record not reflected in the records of neighboring stations. Their method of record combination has the major benefit of allowing relatively short records to be combined together without introducing biases. This approach means that instead of trying to artificially correct for problems detected by comparing individual stations to their neighbors, the researchers can simply treat these as break points, where subsequent measurements from the same site are treated as a separate record and are optimally fit to the larger series.
The inclusion of numerous shorter records should make it easier for researchers to analyze many of the issues (both spurious and serious) that critics have raised about the surface temperature record. These include the changing number of measurement stations available over the last few decades (discussed here recently), the effect of urbanization on the temperature trend, the effect of locating stations at airports, and general station siting issues.
Having additional tools available to tackle these and other potential problems with the surface temperature record can help clarify existing issues and lead to a clearer overall understanding of the global land temperature.
The BEST scientists and academics are also taking the interesting approach of trying to perfect the method prior to running it against the entire data set. They see this approach as helping them avoid any conscious or unconscious bias that might result from knowing interim results prior to optimizing the methodology.
As of mid-March, they had run the method only on a small random sample of all instruments in their data set, though the results from that sample are quite similar to other published temperature series from NASA, NOAA, and the Hadley Center. They have also been using their tool to examine various issues including station siting, airport vs. non-airport sites, and urban heat island effects.
Using Statistics to Quantify Error Ranges
With both statisticians and scientists as part of their project team, the collaboration is seeking to use the best statistical practices to quantify the error ranges for their results. Finally, they have been working on ways to improve the metadata associated with some of the stations, a frequent weak spot.
While the ultimate results of the BEST project are unlikely to dramatically change current scientific understanding of surface warming, they will provide a more robust series incorporating more data than have prior efforts. Their vastly increased station coverage over the last 50 years can be helpful in better addressing a number of potential issues in the surface temperature record. The BEST team is expected to publish its findings over the next two months or so. Those findings are bound to be closely watched and scrutinized by all “sides” of the surface temperature debate looking for ways to bolster their own perspectives.