Contributing Opinion Writer
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The
night before the day that would make him famous, James E. Hansen
listened to a baseball game on the radio. But his mind kept wandering:
What would he say to Congress the next day to convey that humans were
endangering the planet?
He had long been trying to raise the alarm without success, and so had other scientists.
But then, on June 23, 1988 — 30 years ago Saturday — a Colorado senator
named Tim Wirth convened yet another hearing on the topic. Dr. Hansen
was one of several scientists on the witness list.
Few
people had ever heard of him, nor of the obscure NASA unit that he
headed. He and a small group of colleagues studied the Earth’s climate,
working in a suite of offices above the Manhattan diner that “Seinfeld” would later make famous.
He
had conducted rigorous studies of historical temperatures, concluding
that the planet was warming sharply. He had helped to pioneer computer
modeling of the climate, and the results predicted further warming if
people kept pouring greenhouse gases into the atmosphere.
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June
23 turned out be a blistering day in Washington, and much of the nation
was suffering through a drought and heat wave. Dr. Hansen took his seat
in a Capitol Hill hearing room and laid out the scientific facts as
best he understood them.
He had
thought up a good line the night before, during the Yankees game, but in
the moment he forgot to deliver it. When the hearing ended, though,
reporters surrounded him, and he remembered.
“It is time to stop waffling so much,” he said, “and say that the evidence is pretty strong that the greenhouse effect is here.”
His
near certainty that human emissions were already altering the climate
caught the attention of a sweltering nation, catapulting Dr. Hansen to
overnight fame. That year, 1988, would go on to be the hottest in a
global temperature record stretching back to the 19th century.
With the perspective of three decades, it is fair to ask: How right was his forecast?
The
question defies a simple answer. In 1988, Dr. Hansen had to offer a
prognostication not just about how the Earth would respond to greenhouse
gases, but also about how much of those gases humans would choose to
inject into the air.
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He
did what any cautious forecaster would do: He offered low, medium and
high scenarios. The warming over the past 30 years has indeed fallen
well within his upper and lower bounds.
One
of Dr. Hansen’s scenarios, Scenario B, has turned out to be a
reasonably close match for fossil-fuel emissions as they actually
occurred. Yet we now know Scenario B predicted too much global warming,
by something like 30 percent.
Two
reasons for that stand out. One is that Dr. Hansen had assumed a
continued increase in certain refrigerant gases that warm the climate.
Those gases were ultimately brought under control by a global treaty,
the Montreal Protocol — proof that scientific warnings, if taken seriously, can be acted upon at a worldwide scale.
The
bigger problem was that the computers he was using in the 1980s could
not operate fast enough to give a realistic picture of the upper
atmosphere; as a result, his model was most likely overestimating the
Earth’s sensitivity to emissions. In the years since, computer modeling
of the climate, though hardly perfect, has improved.
So
while his temperature forecast was not flawless, in a larger sense, Dr.
Hansen’s 1988 warning has turned out to be entirely on target. As
emissions have soared, the planet has warmed relentlessly, just as he
said it would; 1988 is not even in the top 20 warmest years now. Every
year of this century has been hotter.
The
ocean is rising, as Dr. Hansen predicted, and the pace seems to be
accelerating. The great ice sheets in Greenland and Antarctica are dumping ever-rising volumes of water into the sea. Coastal flooding is increasing rapidly in the United States. The Arctic Ocean ice cap has shrunk drastically.
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If
his warning in 1988 had been met with a national policy to reduce
emissions, other countries might have followed, and the world would be
in much better shape.
But within a
few years after he raised the alarm, fossil-fuel interests and
libertarian ideologues began financing a campaign of lies about climate
research. The issue bogged down in Congress, and to this day that body
has taken no action remotely commensurate with the threat.
Dr.
Hansen retired from NASA in 2013, but at age 77, he feels his work is
not done. Today, from an office at Columbia University, he spends his
time fighting the government he once served. He is an expert witness for
a lawsuit
that young people have filed in Oregon against the federal government,
contending that its failure to tackle climate change is a threat to
their constitutional rights of life and liberty.
His granddaughter, Sophie Kivlehan, is one of the plaintiffs in the case, which has gotten much farther than many legal experts thought it would. The case may go to trial later this year.
Prophets
of impending calamity are rarely thanked for their efforts, especially
when they turn out to be right. But Dr. Hansen did receive a form of
thanks recently, sharing half a of a $1.3 million prize for his attempts to warn the public about the risks of climate change.
The
congressional failure to respond to his warning might be seen now as a
harbinger of the political crisis that has since engulfed the United
States. How can Congress tackle global warming if it lacks the capacity
to solve far smaller problems?
Lately,
Dr. Hansen has been thinking about the connection between the political
crisis and the climate crisis. He is a strong proponent of a new system
of voting, called ranked choice,
that has been adopted in many other countries and a few parts of the
United States, with the goal of recreating a political center.
“It’s very hard to see us fixing the climate,” Dr. Hansen said, “until we fix our democracy.”
Mr. Gillis is a former New York Times environmental reporter and a contributing opinion writer.
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A version of this article appears in print on , on Page SR11 of the New York edition with the headline: He Was Right About The Climate. Order Reprints | Today’s Paper | Subscribe
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