“Half truth” temperature trend claim spurs look at science and media

Fox Island in Narragansett Bay near where some of the temperature records are collected. (Credit: Marc Choquette/(CC BY 2.0)

In 2013, a Rhode Island senator cited a study on warming waters in his home state while urging action on climate change on the Senate floor. Later, he was labeled as telling half-truths by a newspaper fact-checker. In a new study, a scientist behind the temperature numbers in question has revisited the data and come back with new insight on the role of scientists in communicating the results of climate change research.

Climate scientists face a big challenge when it comes to translating the results of their complex calculations to the general public, especially when it comes to temperature records.

Analyzing trends in long-term temperature records would appear to be a clear way to document warming, but the seemingly black-and-white results they produce are subject to variability and uncertainty that don’t translate well into media reports. What’s more, the records have become a lightning rod for climate change skeptics who cry scandal after when they interpret standard scientific data manipulations as book-cooking.

In what is likely the most well-known of those incidents, which came to be “Climategate” in the media, hackers released emails from the servers of the Climatic Research Unit at the University of East Anglia. Skeptics claimed the discussions of data manipulations among top climate scientists in those emails were a smoking gun proving climate change as a hoax, but the scientists were later exonerated.

More recently, the announcement built for headline writers that 2014 was the hottest year on record came under scrutiny in a Daily Mail article that highlighted NASA scientists’ 38 percent certainty that last year was in fact warmer than all previously documented years. Though that article did grapple with scientific uncertainty, it also exaggerated it, according to Washington Post science and environment writer Chris Mooney.

The new study, led by assistant professor Robinson Fulweiler of Boston University, addresses a lower profile incident in which Sen. Sheldon Whitehouse, democratic senator from Rhode Island, said in a speech to the Senate that “Narragansett Bay waters are getting warmer – 4 degrees Fahrenheit warmer in the winter since the 1960s.”

That figure came from a 2009 study co-authored by Fulweiler that looked at water temperature data collected from 1960-2006. The PolitiFact feature of the Providence Journal tracked down another dataset from the same Narragansett Bay site that covered years 1960-2010. They performed their own analysis showing water had warmed just 2.4 degrees Fahrenheit, compared to the 4-degree figure from the 2009 study cited by Whitehouse.

“Because the temperature rise is a little more than half of what he said, we rate his statement Half True,” wrote reporter C. Eugene Emery Jr. in the PolitiFact piece.

Though the Providence Journal doesn’t fall into the same camp as climate conspiracy theorists behind Climategate, its use of a different dataset that covered a longer time period led to a “misunderstanding of long-term temperature data that occurred on the national stage,” the authors wrote in the new study. In response, they took another look at the original dataset, and then analyzed the dataset used by the PolitiFact feature and a third dataset from the National Oceanic and Atmospheric Administration. The results were published online in the journal Estuarine, Coastal and Shelf Science.

When the researchers update their original dataset to include cold-winter years between 2006 and 2010, they found that the winter waters of Narragansett Bay had warmed about 3.4 degrees Fahrenheit from 1960 to 2010 — less than the amount reimported in their 2009 study cited by Whitehouse. Their analysis of the two other temperature datasets showed increases of 2.88 and 3.6 degrees Fahrenheit.

Despite the apparent discrepancy in increases produced by each long-term temperature record, the authors write that the results “are not meaningfully different from one another” when accounting for variability in the models used to calculate the increases. Nor are the updated increases meaningfully different than the original value that earned a “Half Truth” rating from PolitiFact.

All of this concern over different results that are essentially saying the same thing — winter water temperatures in Narragansett Bay have warmed over the past five decades — highlights the “common disconnect between information produced by the scientific community and how it is perceived by the public,” the study authors wrote. They say scientists have a responsibility to take the time to communicate with the public and journalists, especially when it comes to variability associated with averages and summaries.

“There is a continued need for open communication between those who do the science and those who have a voice with which to share it,” the authors wrote. “After all, we are all seeking the whole truth.”

Top image: Fox Island in Narragansett Bay near where some of the temperature records are collected. (Credit: Marc Choquette/CC BY 2.0)