On 30th Anniversary of Famous Climate Testimony, James Hansen Called 'The Paul Revere We Desperately Needed'

Saturday marks the 30th anniversary of James Hansen's prophetic climate warning to Congress.

Commenting on the then-NASA scientist's testimony, climate activist and author Bill McKibben said Hansen took "climate change out of the labs and into public," and called him "the Paul Revere we desperately needed."

"I would like to draw three main conclusions," he told (pdf) a Senate Committee on June 23, 1988. "Number one, the Earth is warmer in 1988 than at any time in the history of instrumental measurements. Number two, the global warming is now large enough that we can ascribe with a high degree of confidence a cause and effect relationship to the greenhouse effect. And number three, our computer climate simulations indicate that the greenhouse effect is already large enough to begin to effect the probability of extreme events such as summer heat waves."

That testimony, meteorologist Bob Henson noted this week, became front page news, and in so doing "the concept of global warming quickly entered public consciousness."

"Over the past 30 years," Henson wrote, "global temperature rise has been close to the middle of three projections offered by Hansen at the time."

Indeed, that projection proved to be "an eerie match to the warming we've seen," said Michael Mann, a climate scientist and director of Penn State's Earth System Science Center at Penn State. In a video published this week by Yale Climate Connections, Mann said, "Hansen has been remarkably prescient when it comes to the predictions he made decades ago and what actually played out. He predicted essentially the warming we've seen three decades ahead of schedule."

In a brief article at The New Yorker marking the "lugubrious milestone" of Hansen's testimony, Elizabeth Kolbert, author of the Pulitzer Prize-winning book The Sixth Extinction, noted that in the decades since then, "nearly half of the Arctic ice cap has melted away, the oceans have acidified, much of the American West has burned, lower Manhattan, South Florida, Houston, and New Orleans have flooded, and average temperatures have continued to climb." Despite such markers, "Washington continues to ignore the problem, or, worse still, to actively impede efforts to address it."

Hansen, for his part, told the Associated Press in a recent interview that he felt no joy in being right, but said he wished "that the warning be heeded and actions be taken."