A guest post by Todd Myers of the Washington Policy Center.
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.