A soft-spoken scientist from Denison, Iowa, stood before a U.S. Senate committee on June 23, 1988, and said, “The greenhouse effect has been detected and is changing our climate now.”

As Saturday’s 30th anniversary of that landmark testimony arrives, media outlets including the New Yorker, the Associated Press and the Yale Climate Connection are documenting scientists’ widely held view that James Hansen’s observations and predictions have proved remarkably accurate. 

“Three decades later, most climate scientists interviewed rave about the accuracy of Hansen’s predictions given the technology of the time,” AP reported. 

He wasn’t the first to make such a statement, but his remarks hit the front page of the New York Times under the headline “Global warming has begun” and drew wide coverage. 

Hansen “got it right,” scientist Stefan Rahmstorf of the Potsdam Institute in Germany told Yale Climate Connections. 

“Amazing … remarkably prescient when it comes to the predictions he made decades ago and how it’s played out,” said Penn State University’s Michael Mann. 

Hansen, who now is retired from NASA, accurately predicted both the magnitude of the warming so far, and the increase in severe weather, scientists said. 

When I was reporting for the Des Moines Register, I visited Hansen in the building that included both his NASA office and the generic-looking diner that served as the facade for a main gathering place for the central characters in the “Seinfeld” series. Hansen told me about growing up in a house of less than 500 square feet with a huge family in Denison, where he would do the neighbor kids’ math homework so they could play football sooner.

Denison is known more for being the hometown of actress Donna Reed, and Hansen’s own brother told me in 2006 that if you polled 100 people in Denison, 95 wouldn’t know about the world-class scientist who grew up in their western Iowa town. 

The beginning of the profile read: “It’s really not an exaggeration. The fate of the Earth as we know it could be shaped dramatically by the world’s response to the scientific studies of a lanky man from Denison, Ia., a shy soul whose warnings about global warming have thrust him onto magazine covers and national television shows and put him squarely in the middle of a scorching controversy.”

Much as Rachel Carson did when she wrote about the dangers of pesticides in “Silent Spring,” Hansen drew all kinds of attacks from various interests, many of them tied to fossil fuel companies with a vested interest in coal and gasoline. He told me he much preferred to be alone in his lab, but as the climate change evidence mounted, he because much more active — some would say activist — in warning that the atmosphere was nearing the point of no return if carbon emissions weren’t sharply reduced. 

That debate remains today.

See a video about Hansen’s predictions.