Compelling Anecdotes Undermine Science Journalism on Climate Change

Today, Real Clear Science features a long piece I wrote on the interplay between the process of science and the storytelling of journalism. The problem arises when journalists substitute compelling anecdotes for scientific data, conflating the two. A recent story in the Seattle Times about one impact of climate change offers a good case study.

On March 5, the Seattle Times published a story highlighting the impact of climate change on the Costa Rican coffee crop, claiming recent declines are related to unpredictable weather caused by the increase of carbon dioxide in the atmosphere.

The story’s headline captures the tone: “Climate change takes toll on coffee growers, drinkers too”. The impact of climate change on coffee, they argue, has been significant. “Yields in Costa Rica have dropped dramatically in the last decade,” the Times wrote, “with farmers and scientists blaming climate change for a significant portion of the troubles.”

But there are factual problems with the story.

(1) According to NASA, Costa Rican temperatures during 2008-09, the years with the largest drop in production, were only 0.6 degrees warmer than the 20th century baseline. The most significant increase occurred in the fall (September-November, 2008), of just over 1 degree F. This was left out of the story.

(2) Average temperatures in 2008-09 were only 0.1 degrees warmer than 1998-2000, when Costa Rican coffee harvests were 68 percent larger. The largest difference occurred in the fall, a difference of only 0.7 degrees.

(3) Temperatures in 2008-09 are actually 0.1 degrees lower than the average annual temperature during the 1991-93 period, which marked the country’s highest coffee production.

Even the climate scientist chosen by the Seattle Times to participate in an online chat about the story threw cold water on the link between the crop declines and climate change. Dr. Mike Wallace, a climate scientist at the University of Washington told me “the warming of the past 10 years is pretty small, both globally and over Costa Rica. I’m not at all sure that it’s been a factor in the decline of coffee production on this short time scale.”

Science journalism can be especially susceptible to the urge to substitute a simple, compelling story for the complexity of data-based science. Reporting the uncertainties of scientific information may not result in gripping journalism, but it is critical to enabling the public and policymakers to rely on the stories they read about climate change or the other environmental challenges we face.

You can read the entire piece at Real Clear Science. A longer version of the analysis is available at the Washington Policy Center.

Comments (1)

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  1. Tee says:

    Excellent analysis! … I will be reading the shorter piece. Notably, reading media reports of the original article definitely skewed my opinion as to the causation of crop yield reduction, and without this analysis I probably would have left it at that. Seems to suggest some agronomy research is in order to find the true basis for multivariate yield reductions. Thanks!

    – Tee

    Tee is the founder and senior editor of Costa Rica CLOSEUP a Travel Guide to Costa Rica with Events, Articles and Information for everyone traveling, retiring and/or purchasing real estate in Costa Rica. Please visit for more information.

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