For William Gray, a lean, six-foot-five emeritus professor at Colorado State University and one of the world's leading experts on tropical storms, the bugaboo on the horizon is another tall, charismatic fellow named Albert Arnold Gore Jr. You can call him Al.
Sitting in his office on the northwest edge of Fort Collins, Gray thumbs through Gore's An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It, the coffee-table companion book to the documentary of the same name. Gore has been making the rounds of talk shows and bookseller conventions promoting both efforts. Turn on cable news and there he is, reciting the we're-in-deep-shit message he's been delivering by slide show for years, now bolstered by a website (www.climatecrisis.net) and startling computer graphics that depict the earth being ravaged by a gauntlet of man-made catastrophes over the next few decades.
Gray doesn't believe in the planetary emergency. Never has. Still, he picks his words carefully. A few weeks ago, a Washington Post article quoted him comparing Gore's convictions about global warming to Hitler's beliefs about the Jews, a burst of rhetorical overkill he says he sincerely regrets. So he's going to try to sound a diplomatic note here, even though the book, which some colleagues have asked him to review, strikes him as a piece of outright hysteria.
"I admire Al Gore," he says. "There's no doubt, with over six billion people, we have a lot of environmental problems in this world. He's pointing them out. That's fine. But that doesn't mean it's all due to global warming, or that you're going to solve these problems by cutting back on fossil fuels."
The tone seems conciliatory enough. But soon Gray is out of his seat, pointing out features on a map of the world pinned to the wall, reading passages from Gore's book aloud, scribbling lines of convection on a yellow legal pad. "This is a slick propaganda book," he declares. "The pictures are very good. But there are factual errors."
He's off and running. The people who are spreading the global-warming alarm, including the scientists, just don't understand the way the atmosphere works, he says. The ones who see a link between increasing ocean temperatures and more intense hurricanes in recent decades don't understand the ocean or hurricanes. The global computer models projecting that heat-trapping greenhouse gases will warm the earth between three and seven degrees Fahrenheit in the next hundred years -- melting polar ice, flooding shorelines and disrupting weather patterns everywhere -- are fatally flawed.
Now 76 years old, Gray is an old-school meterologist who prefers observational data to computer modeling. "I could assemble fifty of my colleagues who are very skeptical about global warming," he says. "The IPCC [Intergovernmental Panel on Climate Change] never talks to us, but I have a bit of an obligation, at my age -- I was trained to tell the truth. There's a lot of hogwash in this. If I don't speak up, I'm not doing my job."
Colorado's Front Range is a hotbed of research on climate change, from CSU's Department of Atmospheric Science to the strong presence in Boulder of the National Center for Atmospheric Research (NCAR) and the National Oceanic and Atmospheric Administration (NOAA), which operates several labs as well as joint research projects with the University of Colorado and CSU. Gray has been a prominent figure on the scene -- and an increasingly vocal skeptic of global warming claims for the past decade or so ("Global Warning," October 9, 1997). But his role in the debate has exploded in recent months, as intense hurricane activity has triggered a spate of theories and scientific papers linking the extreme weather to rising global temperatures.
Gray has been tracking hurricanes for half a century. "All these guys are very talented," he says of the scientists who are looking at hurricanes as indicators of the damage that increased greenhouse gases are inflicting on the planet. "Good talkers. But that doesn't mean they know how the atmosphere ticks. They haven't been down in the trenches. They can't hold their own with me."
Determined to set the record straight, Gray has lashed out at his colleagues over and over again in op-ed pieces, interviews and Senate testimony. He's taken the fight from the trenches of Discover to the front page of the Wall Street Journal. The argument has become heated and, at times, bruisingly personal -- so much so that several leading climate researchers will no longer appear on a panel with him or debate him at conferences. "Bill and I used to have, as the British say, 'jolly arguments,'" sighs Peter Webster, a professor at Georgia Institute of Technology who once co-authored a paper with Gray but has since become one of his targets. "But they've ceased to be fun."
Gray's contrarian position is an uncomfortable subject in the climate community. Most global-warming skeptics are routinely discounted as crackpots or shills for the fossil-fuel industry. But Gray says he's received no money from energy companies, beyond reimbursing his expenses for traveling to a conference or two; in fact, he claims that funding for his own research has suffered as a result of his views. And his credentials are formidable. He's a towering figure in hurricane circles and has supervised graduate work by dozens of well-known storm researchers, including top staffers at NCAR and the National Hurricane Center.
"In tropical cyclones, he's got the best legacy of anyone," says Greg Holland, a senior scientist at NCAR who did his doctoral work under Gray -- and now finds himself at odds with his former mentor's theories. "He's got former students running major organizations around the world."
Their criticism of Gray has nothing to do with his age or his politics, and a lot to do with his science and his personal conduct, his opponents say. Gray's view that the earth's bump in temperature over the past few decades -- nineteen of the twenty hottest years on record have occurred in the last quarter-century -- is primarily a result of natural processes, not industry-generated greenhouse gases, has yet to cohere into peer-reviewed research. But he continues to hammer away at other scientists, ridiculing their computer models and talking about "agenda-driven science" and a global-warming "hoax" perpetrated in order to obtain funding for more research.
"They say I insult them," he says, chuckling, "because I bring up this one verboten thing, the motivation for their research."
But weeding out agendas in climate research is no easy task these days. "Climate change is shot through with politics," notes Roger Pielke Jr., a CU professor of environmental studies who specializes in science policy issues. "There's no such thing as a pure science of climate change anymore, because it's such a political issue."
The popular notion of the global-warming debate is "a cartoonish image of alarmists on one side and skeptics on the other," Pielke says, but the underlying situation is more complicated. He considers himself a "non-skeptic heretic" in the fray, someone who accepts that global warming is occurring but questions the knee-jerk policy responses -- for example, the simplistic notion that cutting carbon-dioxide emissions will prevent future mega-storms like Katrina.
"One of the frustrations is that this has become a proxy war for something else," he says. "It's devolved into a battle to make everyone think the same as a prerequisite to taking action. That's not how politics works."
"It's become like debating abortion," says Phil Klotzbach, a doctoral candidate at CSU who's taken the lead in the annual hurricane-forecasting program that Gray, his advisor, launched 22 years ago. "People need to look at the data and see what the data shows rather than having blinders on."
Klotzbach has tried to steer clear of the larger global-warming furor, preferring to focus on hurricanes in his work. But he sees value in Gray's self-appointed role as a skeptic. "He's one of the few dissenting voices, and it's important to have another perspective," he says.
There are people who embrace Gray as a plain-speaking tribal elder, a kind of braking mechanism on a movement they think is speeding toward too-hasty conclusions, fueled by an alarmist popular media that loves doomsday stories and is eager to put to rest any uncertainties about our peril. ("In the past five years or so, the serious debate has quietly ended," Time declared in a recent overheated cover story.) There are others who regard him as needlessly stirring controversy with inflammatory statements, playing into the hands of global-warming naysayers at a time when calm analysis and serious action is required. And there are some, longtime admirers he's alienated or dismayed, who fear that the scientific reputation Gray's insulting the most is his own.
But Gray plans to keep to his stormy path. His wife passed away a few years ago, his kids are grown, and his days are no longer filled with classes and faculty meetings. "I'm going to give the rest of my life to working on this stuff," he says. "I'm going to keep going until they put me in a box. I like what Dylan Thomas said about going kicking and screaming into the dark night."
The first hurricane Bill Gray got to know intimately was Helene, the wildest gal of the entire 1958 season. He flew into her arms in a B-50 Superfortress, a bomber converted to reconnaissance work, as she skirted the coast of the Carolinas. His mentor, Herbert Riehl, talked the pilot into staying around 1,500 feet, so that he and Gray could observe from the canopy the workings of the storm below. As washboard turbulence buffeted the plane and the wind screamed at 150 miles per hour, Gray had a good look at the kind of raw fury that sea and air could conspire to summon.
"It was exciting," he recalls. "I think we took Dramamine."
Growing up in Washington, D.C., Gray had been obsessed with baseball. He was a right-handed pitcher of some promise, but a bum knee kept him out of the majors. The possibility of getting drafted during the Korean War prompted him to enlist in the Air Force. He'd majored in geography as an undergraduate, and his grades were good enough to get him into a weather-forecasting program. The Air Force sent him to the University of Chicago to study meteorology for a year; after his service was up, he returned to Chicago to do graduate work with Riehl, a pioneer in the study of tropical storms. Riehl soon moved to CSU to launch its atmospheric-science department. Gray followed, joining the faculty in 1961.
From the outset, Gray's research revolved around the formation, intensity, structure and motion of tropical storms. Like Riehl, he believed passionately in getting down in the trenches, even if it meant getting up in the air. Every year he went to Florida to fly into storms and collect data. Coastal officials, insurance companies and others were keenly interested in developing a reliable method for forecasting the hurricane season, but the Atlantic storms showed tremendous variability from year to year, and nothing Gray was finding out seemed to indicate how active the season might be.
By looking further afield, though, he began to detect patterns. The answers weren't in Florida. Some of them were on the other side of the world. Teaching tropical meteorology had made Gray familiar with the years that the Pacific warming events known as El Niño were at their strongest; in those years, the Atlantic turned out to be less active. Then he began to notice a relationship between hurricanes in the Atlantic and strange winds in the tropics stratosphere known as QBIOs, short for quasi-biannual oscillation: The winds blow from a westerly direction for twelve to fourteen months, then reverse their course for another twelve to fourteen months. As weather balloons improved in the 1960s and researchers began to get better data on the winds, Gray was able to see that the westerly QBIOs were linked to major Atlantic storms. Other factors -- the amount of rain in West Africa, the sea-level pressure in the Caribbean -- also seemed to provide good indicators of the Atlantic storm season months in advance.
"The problem was that we'd been looking locally," Gray recalls. "You had to look globally."
Gray released his first public forecast for the upcoming hurricane season in 1984. He predicted seven actual hurricanes (five developed) and ten named storms (twelve became significant enough to be named). Over the years, the CSU team has fine-tuned its methods and now claims 95 percent accuracy in determining whether a given season is going to be above or below average; the annual prediction is eagerly anticipated and reported on in hurricane-prone states. (Gray and Klotzbach expect this year to be only somewhat less horrendous than 2005: nine hurricanes, including five monsters, and seventeen named storms).
Yet for all his renown as a forecaster, Gray is wary of any methodology that claims to accurately track weather more than a few days ahead. His own predictions rely a great deal on "hindcasting," looking at key conditions several months before the hurricane season begins and matching them up with similar conditions as documented in the historical data of previous years. He's convinced that the climate is far too complicated for even the most powerful computers to forecast accurately years in advance -- which is one of his quarrels with the global-warming crowd.
Gray accepts that the earth has gotten warmer over the past century, particularly in the past three decades. He doesn't deny that heat-trapping gases generated by human activity, particularly carbon dioxide, have increased significantly, too. But it's the connections that researchers have drawn between these developments, and the way they've transformed the data into computer-generated scenarios of decades-spanning disaster that has him gnashing his teeth.
Although many factors contribute to climate change, the most sinister component, in many scientists' view, is carbon dioxide. Thanks largely to the burning of fossil fuels, the atmospheric level of CO2 has shot up to 381 parts per million, 37 percent higher than pre-industrial levels, and the pace is accelerating. Yet by itself, CO2 is hardly a pervasive threat; even doubling its concentration in experiments doesn't seem to trap a great deal more heat. The interaction of CO2 and water vapor, a much more common greenhouse gas, is another matter. One of the primary tenets of global warming is that carbon dioxide acts as a water-vapor "trigger" high in the atmosphere, trapping enough heat to moisten the air. As the air retains moisture, it warms further, creating a positive-feedback loop that drives the temperature higher and higher and keeps more heat from escaping in the form of radiation into space.
Gray disputes this. He's convinced that the calculations of the warming proponents fail to take into account the effect of increased global rainfall (as a result of surface warming and evaporation) on upper-atmosphere water-vapor levels. He's argued that "rainfall efficiency" will increase, and so will heat loss to space -- compensating, for the most part, for the rising levels of CO2. The computer models have exaggerated the feedback loop, he insists, and don't realistically simulate complex oceanic and atmospheric processes. "That's a big flaw in the models," he says, "and it's going to do them in."
In his war on the feedback loop, Gray has an ally of sorts in Richard Lindzen, an MIT professor and ardent critic of "climate alarmism," who's theorized that the behavior of upper-level cirrus clouds could counteract the warming effects of CO2. Clouds are a tricky issue in climate projections, since they can reflect light energy as well as trap heat. But Lindzen's and Gray's arguments have been widely challenged -- including by each other. Gray has referred to Lindzen's theory as a red herring, while Lindzen has termed Gray's grasp of the theoretical as "frustratingly poor."
"One of his students said that Lindzen is only half as smart as he thinks he is, but that still makes him twice as smart as anybody else," Gray says. "I respect him tremendously for the stand he's taken, but we can't work together as scientists."
Gray contends that the computer models haven't received the scrutiny they deserve and seem to be designed to concur with each other rather than real meteorological processes. But scientists who run the models say that argument was more valid a decade ago, when the technology was much less sophisticated and the processes being studied less understood than they are today. The latest generation of supercomputers have greatly improved spatial resolution, allowing for more detailed studies of regional climate. They're also better able to re-create actual climate changes over the past century, allowing for greater analysis of global trends and more intricate scenarios of future developments.
"We now routinely try to simulate twentieth-century climate," says Jerry Meehl, an NCAR senior scientist involved in computer-modeling projects that often draw on networks of computers around the globe. "To do that, we usually start the model sometime in the late 1800s and put in factors that we know affected the climate -- greenhouse gases, ozone, sulfate aerosols, solar variability, volcanic eruptions and so on. The results help us understand what we observed the climate doing, and that gives us some confidence that we can trust what they have to say about the future."
Meehl says the models have helped explain one of the great climate mysteries of the twentieth century. The earth warmed significantly in the first five decades of the century, then cooled until the mid-1970s. The industrialized world was pumping out increasing levels of greenhouse gases during the latter period, so why wasn't the temperature increasing? The answer, researchers concluded, was that increased industrial pollution after World War II blocked solar radiation, lowering temperatures and prompting some short-lived speculation about a coming "ice age."
"In the 1970s, North American and Western European countries started cleaning up their emissions," Meehl explains. "That reduced the load of the aerosols while the greenhouse gases were relentlessly increasing, and it's been warming ever since."
Meehl acknowledges that there are still multiple sources of uncertainty in any climate projections: "Nobody knows what's going to happen in the next hundred years in terms of population growth, energy usage or economic development in various countries. You get a range of possible future climates based on whatever assumptions you make. But we're in a fortunate position of having a lot of models to look at."
Clouds are still a tough problem, but the data is getting better, thanks to improved satellite coverage. And despite some variations in results, several major modeling projects indicate a positive feedback loop involving water vapor. Even if all greenhouse-gas emissions were magically stabilized at year 2000 levels, NCAR's models show another half-degree Centigrade of global warming over the next century, simply because of the processes already at work. "We're already committed to a certain amount of climate change based on what we've already done," Meehl says.
But Gray rejects the models, and believes he's paid a price for knocking the computer crowd. In recent years, he's struggled to keep his forecasting program going. Although the National Science Foundation still kicks in some funds, he figures he's put in $100,000 of his own money over the years, including a $45,000 stopgap payment a couple of years ago. And he's been turned down repeatedly in his quest for research monies from other sources.
"I have had problems keeping my shop going, particularly since the Clinton administration came in," he says. "I never got a NOAA grant after that. I must have been turned down thirteen times. These guys were getting money to run these big models, and they were bending their objectivity to get the money. You've got to go along with the crowd."
Gray says he isn't talking about his friends at NCAR in particular. ("I like Jerry Meehl," he adds. "I just don't believe him.") But his resentment over the funding issue is palpable. Lindzen made a strikingly similar argument in a recent Wall Street Journal column: "Scientists who dissent from the alarmism have seen their grant funds disappear, their work derided, and themselves libeled as industry stooges, scientific hacks or worse."
But other scientists familiar with the grant process scoff at such charges. Some accuse the Bush administration of trying to downplay global warming, a charge echoed in Gore's movie.
Georgia Tech's Webster says he's been part of the anonymous peer review on several of Gray's NSF proposals. Each time, he says, he recommended funding for Gray's hurricane research but turned down the global-warming research component because he believed it wasn't up to standards. "I have helped Bill get funding over the years," he says. "This year, I was asked to review his proposal, and I had to recuse myself because of the ad hominem attacks he's been making."
NCAR's Holland points out that his own research isn't dependent on academic grants at all. "I would be getting exactly the same funding if I was saying nothing about tropical cyclones and climate change," he says. "Getting support for research goes through a well-established peer review. Bill's not losing out to the American modeling people; there's still plenty of funding for good observational work. The lack of funding for Bill's research is related to the quality of his research."
A key scene in the film An Inconvenient Truth is the moment Al Gore reveals that we are literally reaping the whirlwind. He stands on a stage, palms up in silent supplication, while images of a flooded New Orleans play on a big screen behind him. Pump enough crap in the air, the ocean warms up, and boom! -- Katrina trashes the Gulf Coast.
Such oversimplified notions of cause and effect exasperate Bill Gray. The scientists who've tackled the global-warming/ hurricane connection -- currently one of the hottest questions in science -- have stopped far short of blaming any one storm or season on CO2 emissions. But some have concluded that rising temperatures over the past three decades have produced more intense storms, and that a growing number of monster hurricanes should be expected in an increasingly warmer world. Such statements are greeted in Gray's office like a shot across the bow. The global-warming crowd has taken the battle to his turf.
The first major salvo was fired two years ago by Kevin Trenberth, head of climate analysis at NCAR, who suggested that warmer oceans were producing stronger hurricanes. That was followed by a paper last summer from Kerry Emanuel, a well-respected hurricane expert at MIT, who re-examined historical data and found the intensity of storms in the Atlantic had basically doubled in thirty years, a phenomenon he attributed to rising water temperatures linked to global warming. Then came a study by NCAR's Holland, Webster and two other Georgia Tech researchers, Judith Curry and H.R. Chang, who'd set out to challenge Trenberth's work but concluded that the number of intense tropical storms had doubled around the world since 1970.
Gray took them all on. There are too many factors besides sea-surface temperature that influence hurricane intensity, he insisted. The data his colleagues were using was suspect, he told reporters, because of erratic weather information-gathering methods in certain parts of the world in the 1970s. They were playing with numbers and ignoring the cyclical nature of hurricane seasons. You want to talk busy hurricane seasons? How about 1933? From 1933 until 1965, the Florida peninsula was hit by major storms eleven times. From 1966 until 2003, it was hit only once. Up until the last two seasons, in fact, there'd been a great downturn in major storms making landfall, despite increased activity in the Atlantic.
"Had the last two years not had such bad hurricane damage, we wouldn't be talking about it now," he says.
Gray was hardly alone in his dissent. NOAA officials denied that global warming had anything to do with current hurricane patterns, which were "due to natural fluctuations and cycles." Chris Landsea, a former Gray student who now works as science operations officer at NOAA's National Hurricane Center in Miami, re-crunched the numbers and found no increase in the number or intensity of Category 4 and 5 hurricanes globally over the past fifteen years; by his calculations, even a four-degree increase in ocean temperature by the end of this century would have only a small effect on hurricane intensity. CSU's Klotzbach zeroed in on the past twenty years of storm data, considered more reliable than that of previous years, and found a large increase in major North Atlantic storms and a large decrease in Northeast Pacific ones, but no global trend that would support the notion that global warming is whipping up stronger hurricanes.
The rebuttals have prompted a flurry of additional papers and responses; Georgia Tech's Curry, for example, has suggested that Klotzbach is "cherry-picking" his data. But the most biting exchanges have involved Gray's critiques and the counter-volleys. Gray has "brain fossilization," Curry told a Wall Street Journal reporter a few weeks ago, and "nobody except a few groupies wants to hear what he has to say."
Stung, Gray has responded in kind. "I've always liked her, but she doesn't know a damn thing about tropical storms," he says. "They want to put me on the fringe, sure. My brain is fossilized. I'm an old curmudgeon who doesn't change with the times. They use anything they can against you."
Webster says he's tried to keep the debate with Gray on the scientific high ground, without success. "Bill, for some very good reasons, has been the go-to man on hurricanes for the last 35 years," he says. "All of a sudden there are a lot of people saying things Bill doesn't agree with. And they're getting a lot of press -- more press than I like, actually. I like the ivory tower. But he's become more and more radical."
Shortly after his paper was published, Webster recalls, "I had a conversation with Bill in which he said he'd have to 'take me down.' Then I started getting messages from reporters, asking, 'What's this about you taking money? What's this about voodoo science?'"
After Gray questioned Emanuel's motives in a debate at an American Meteorological Society meeting in Florida, other researchers began to avoid public dialogue with him. Holland withdrew from a joint appearance with Gray on an AMS panel in Atlanta last February.
"Bill has always been a natural thinker, the sort of person who asks difficult questions," Holland says. "The unfortunate difference now is the way personalities are being brought into it -- and the denigration of perfectly good scientific techniques."
Gray was dropped from a similar panel with Webster and Emanuel this spring -- because, Webster says, he couldn't get Gray "to promise to be a gentleman" and stick to the science. "I certainly wasn't going to stand in public and let Bill berate me," he notes.
Eight years ago, Holland, Webster and Gray were among an impressive list of co-authors of a scientific paper that suggested global warming could have a modest effect on hurricane intensity. Since that time, they've parted company -- Holland and Webster seeing an ever-more-significant role for warming, Gray denying that it plays much of a role at all.
"I don't think there's much argument now about global warming itself," Webster says. "The records, the models and the theory all point in the same direction. It's a matter of degree."
Gray's scathing criticism of others' research has put more pressure on him to come up with a plausible alternative explanation of the climate's warming signals. This has proved to be a daunting task. Gray thinks the answer lies with the Atlantic Thermohaline Circulation (THC), which he describes as a kind of "hydrologic thermostat" that conveys deep, cold-saline water and warmer, less salty currents around the globe. As the circulation surges or weakens, he contends, the earth goes through periods of cooling and warming.
"Overall, the globe has warmed over the past 120 years," he says. "That's due, in my view, to a multi-century slowing of the thermohaline. We're coming out of a little ice age, and overall, the thermohaline has been slowing. But that doesn't mean it doesn't speed up for thirty or forty years."
Gray claims that the THC is getting stronger, and that within a few years the earth will begin to cool again. Most studies of changes in the ocean climate are mere snapshots, he adds; they don't take a long enough view of the data to detect the THC at work. Yet his own writings on the subject seem more intuitive than empirical. They express a kind of peculiar faith that natural ocean processes are too mighty to be changed by man -- or fixed by him.
Gray's ideas about the THC and its role in global warming have been blasted on RealClimate.org, a lively website run by climate scientists who often duel with the skeptics. "It is all seat-of-the-pants stuff of a sort that was common in the early days of climate studies," the site notes, "but which is difficult to evaluate when viewed as a scientific hypothesis."
Preoccupied with his forecasting, Gray acknowledges that he hasn't devoted the time to researching the THC that it deserves. "I'm not satisfied that I understand the thing," he says.
Now that he's retired, he's yearning to dive into climate data going back to the 1940s that NOAA is in the process of re-analyzing to detect new global patterns. He plans to write a book on tropical storms and some "long articles" on global-warming issues.
"I am inundated with data," he says. "I am studying this in a serious way. I wish I was twenty years younger and had this to look forward to."
CU's Pielke believes the hurricane controversy is too complex to find a speedy resolution. "I think hurricanes will be a focus of debate for years and maybe even decades," he says. "If dealing with climate policy depends on resolving the debate to the satisfaction of all the scientists, then we're in trouble."
On the wall of Gray's office, there's a photograph of the hurricane-chaser posing with one of his all-time heroes, novelist Michael Crichton, whose potboiling bestseller State of Fear revolves around a radical environmental group's evil conspiracy to exploit fears about global warming. "The work of science has nothing whatever to do with consensus," Crichton has written. "Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you're being had."
The picture was taken last fall, when Gray was in Washington to testify before the U.S. Senate Environment and Public Works Committee. The hearings featured a parade of skeptics invited by the committee's chair, Oklahoma Republican James Inhofe, who's declared that global warming "might be the greatest hoax ever perpetrated on the American people."
Given the company he keeps, it would be easy to lump Gray in with the "so-called skeptics" Al Gore routinely disparages, suggesting that all doubts about global warming can be traced back to the interests of the fossil-fuel giants. But there's nothing feigned about Gray's skepticism, and no apparent political agenda. He says he's been a "flaming liberal" most of his life; he voted twice for Clinton-Gore even as the administration was cutting his funds. And his views on the environment wouldn't sound out of place at a Sierra Club meeting.
"Certainly, burning fossil fuels has led to tremendous problems," he says. "We should be putting money into alternate energy sources and making more efficient use of our fuels. But we should be doing that for its own sake. Don't fly this under a false flag, that we're doing it to stop global warming. If it's a little cooler in fifteen or twenty years, and it becomes evident the warming of the last hundred years is primarily due to ocean circulation changes, then we'll look back on this and say, ŒHow can you trust science?'"
By Gray's estimates -- which discount water-vapor feedback and other amplifying forces at work in most global-warming scenarios -- a doubling of carbon dioxide in the atmosphere will only result in a slight increase in global temperature, along the lines of .15 to .2 degrees Centigrade. That's two-tenths of a degree, not the two-to-five-degree range that the models have been projecting. But what if he's wrong?
"There's nothing we can do about it anyway," he says. "We're not going to stop burning fossil fuels. China and India aren't going to stop. The little amount you might be able to cut out is negligible, and it's going to hurt the middle class."
Gore, of course, contends that it's possible to reduce carbon emissions drastically and create jobs at the same time.
Meanwhile, the evidence of man's impact on the climate continues to mount. Last week, the National Research Council released a report confirming earlier studies that indicate the last quarter-century was the hottest period on Earth in 400 years -- and possibly in the last thousand years.
The June 27 issue of Geophysical Research Letters features a new analysis by NCAR's Trenberth and Dennis Shea of worldwide sea-surface temperatures (SSTs) since the early twentieth century. By separating out natural phenomena from the temperature rise associated with man-made activities, Shea and Trenberth calculate that global warming accounts for roughly half the 1.7-degree Fahrenheit rise in average SSTs in the tropical Atlantic since 1970. In other words, while natural cycles contribute to variation in temperature, man's influence is now seen as a significant force that "increases the risk of future enhancements in hurricane activity," Trenberth says.
The paper will doubtless touch off a wave of critiques and responses, many of them from the record number of researchers who submitted hurricane-related papers to AMS conferences this years. NCAR's Holland says the explosion of interest in tropical storms has been good for the field. "At the scientific level, skepticism is part of the process," he notes. "The process wouldn't work if we didn't have that."
Holland says he's eagerly awaiting Gray's first peer-reviewed contribution to the discussion. Gray says he's working on it. But he'll have to rein in his usual rhetoric; his incendiary style may have as much to do with his pariah status as with his contrarian ideas. Even Klotzbach, who praises his prof's "historical perspective" and vast knowledge, acknowledges that his outspokenness can pose problems.
"I do try to get him to tone it down a bit," he says. "Whenever I go away, I tell the secretary not to let him send anything out until I get back."
But Gray has reasons to be impatient. "I feel the Grim Reaper chasing me," he says. "You have no idea how I've been working on this."
Gray expects the globe to start showing signs of a cooling trend in the next few years, and he hopes to be around to see the results of his forecast. "When I am pushing up daisies, I am very sure that we will find that humans have warmed the globe slightly, but that it's nothing like what they're saying," he predicts. "I just don't want to die and leave all these loose ends."
