A crop-searing drought grips the Midwest and Southeast. In the Rocky Mountains, extraordinary "superfires" rip through thousands of acres of high-elevation pine. The Mississippi River runs so low that barge traffic must be slowed, at times suspended. Across the country, roads buckle under the heat.

The year is 1988, and for the first time, a majority of Americans are waking up to a disconcerting phenomenon known as the greenhouse effect.

Coming on the heels of decades of research, the 1988 North American drought bridged the gap between scientific and popular understanding, pulling climate change down out of the atmosphere and planting it firmly in the minds of the U.S. public. From that union came the U.N.-sponsored Intergovernmental Panel on Climate Change, the modern climate movement and its counterpart, the climate skeptic movement.

Jim Hansen

More than two decades later, the drought of 2012 has reignited national interest in global warming. National news coverage is up, and a recent poll found that recognition of climate change rose 5 percent on the back of the July heat wave.

Yet the debate today is framed within fundamentally different parameters, polarized by party lines and upstaged at every turn by the woes of a flagging global economy. For a significant portion of Americans, belief in climate change seems inextricably linked to the weather, rising with the temperature only to fade again as the seasons turn.

"It's a two-edge sword you're grasping when you talk about hot weather [as an indicator of] climate," said Kenneth Green, a resident scholar and energy expert at the American Enterprise Institute. "When it's hot, the public's views go towards climate change. When it's cold, they swing the other way."

He added, "Weather is not climate. It's disingenuous to link the two."

The surge of public interest accompanying the drought of 1988 receded almost as quickly as it advanced. Today, as the nation enters high summer in what could shape up to be its hottest year on record, belief in climate change is again on the rise. But for how long, neither climate scientists nor sociologists can say.


'It is already happening'

On a stifling day in June 1988, climatologist Syukuro Manabe stood by a whirring projector, shuffling through transparencies, as a room of sweating Congress members shifted uncomfortably in their seats. Close by, James Hansen of NASA was waxing to the apex of his testimony.

"Global warming has reached a level such that we can ascribe with a high degree of confidence a cause-and-effect relationship between the greenhouse effect and observed warming," Hansen told the assembled representatives. "It is already happening now."

At the invitation of then-Sen. Timothy Wirth (D-Colo.), the two scientists had come before a congressional committee to testify on a phenomenon that, until that day, would barely have registered in the minds of more than half of Americans: man-made global warming, or the process of trapping heat in the atmosphere through the release of greenhouse gases.

"I think that room full of congressmen, they were very much afraid that [the summer of 1988] might now be every summer," Manabe, now a professor at Princeton University, recalled recently. "It wasn't just the heat -- it was the dryness. There was worry in that room that the U.S. might turn into a desert."

The timing of the testimony was no accident. Wirth had been arguing for action on global warming for several years. Hansen had already testified before congressional committees in 1986 and 1987, drawing little public attention, and with the summer drought, he and the scientists recognized their opportunity to reach the public.

As an aide for Wirth would later tell Grist Magazine, "We did agree that we should figure out when it'd be really hot in Washington. People might be thinking of things like, what's the climate like?"

The gamble paid off, and newspapers leapt on the story. Following Hansen's testimony and in the ensuing months, knowledge of climate change rose to 68 percent among Americans, a significant increase from 38 percent less than a decade before. Coverage of the issue in U.S. newspapers rose tenfold in the latter half of 1988, according to a survey conducted by climate historian Spencer Weart.

"There's no question about it," Weart said. "The drought events of '88 catalyzed a huge spike in public perception."

Climate or weather? And does it matter?

In the coverage that followed, climate scientists were suddenly thrust into the limelight. For the first time, the public was avidly attentive to what they had to say. After decades of accumulating research, many were equally ready to speak.

The same June that Hansen and Manabe delivered their testimonies, a panel of pre-eminent climate scientists in Toronto issued a sharp warning, stating, "Humanity is conducting an unintended, uncontrolled, globally pervasive experiment whose ultimate consequences could be second only to a global nuclear war."

Within the U.S. government, about 30 climate bills floated before Congress; in December, the U.N. General Assembly issued Resolution 43/53, calling for the creation of the Intergovernmental Panel on Climate Change.

But there was confusion, too. The public was looking for answers on the cause of the summer's drought -- answers that climatologists, who study global patterns larger than a single weather event, could not provide.

Meteorologists could provide those answers, and they eventually did. The drought was caused by "massive, naturally occurring climatic forces in the tropical Pacific Ocean and had little to do with global warming caused by the greenhouse effect," one January 1989 New York Times banner read.

Many of the newspapers that quoted Hansen misinterpreted his testimony, linking his comments directly to the summer's heat. He had not made that connection. Though clearly exploiting the drought as backdrop, his testimony made no attempt to attribute it solely to global climate trends. Unaware of the newspapers' mistake, however, many scientists rebuked Hansen for overstepping his bounds.

By contrast, Manabe's more tempered comments generated little controversy and, consequently, little attention.

"I was trying to explain the physical mechanisms of midcontinental summer dryness to a room full of overheated senators, with this terrible Japanese accent," he recalled. "I was telling them that they couldn't blame one event on global warming. It's not just hot temperatures, or one dry summer."

He added, "I don't think I helped convince them of much of anything."

When the public loses interest

The wave rose, crested and finally broke. Though drought persisted into the spring of 1989, by the end of that year the momentum had started to roll back.

"I think you saw some backlash against the notion" that a drought year could evidence global warming, said Shelly Ungar, a professor of sociology at the University of Toronto who has studied public opinion on climate change for several decades.

The emerging climate skeptic movement in particular leapt on the perceived confusion, he said, holding it up as evidence that the science behind climate change was flawed, exaggerated and otherwise unreliable.

But the real reason for the lag in interest was much simpler and much more mundane, Ungar said. The public simply moved on.

"Our attention waned," he said. "The news is driven by whatever's timely -- the next crime, the next crisis. But climate has its own built-in cycle. A cold winter comes, and then it goes away. The next winter is better. And so our attention hops from the ozone hole to climate to the next thing."

As the weather returned to normal, agitation over climate change receded, much as fear of nuclear war and communism had gone before it.

"The problem is, climate change doesn't go away," Ungar added.

The gradual march of science

One community hasn't let the climate question go. Among scientists, the swell of 1988 helped cement climate change as a real and pressing issue that spanned disciplines.

"You saw a shift in the locus of power" in the decade after 1988, said Irving Mintzer, a senior policy adviser at the Potomac Energy Fund and a longtime expert on energy technology. "The issue expanded from the realm of physical scientists and climatologists to include biologists, agronomists, health experts, and, increasingly, social scientists, political scientists and even lawyers."

It took decades for scientists to build up the base of evidence that allowed Hansen, in 1988, to testify that the community was "99 percent certain" that global warming was taking place. In the decades that followed, that evidence continued to accumulate, refined and expanded on by advances in technology and the computer models scientists like Manabe had helped to pioneer.

As the Victorian poet Alfred, Lord Tennyson, once wrote, "Science moves, but slowly, slowly, creeping from point to point."

Public perception swelled and receded as the first Rio Earth Summit, the Kyoto Accord and subsequent climate conferences came and went. As time lent the concept familiarity, climate change took on a new dichotomy. Before, its principal division had been between those who had heard of the concept and those who hadn't, but now disagreement over global warming began to fall along political lines.

Belief in climate change among Americans is currently at 70 percent, up from only 58 percent two years ago. Yet a cool winter or two could see that figure slide again, as it did in the early 1990s.

For all their similarities, though, the droughts of 1988 and 2012 are not identical. The planet is now warmer, on average, than it was a quarter-century ago, and if the year continues as projected, it will be North America's hottest on record. Weather oscillates, but in a warming world, the oscillations trend upward.

To make that message stick, the climate movement will need to change its rhetoric, Mintzer said. "We need to get away from this rhetoric about global warming and start talking about global weirding," he said. "Maybe you have a flood in Pakistan one year and a fire in Russia the next, then a drought in the United States followed by record cold in Europe. These are all pieces of the same picture."