The National Center for Atmospheric Research (NCAR), one of the top climate laboratories in the world, is headquartered in Boulder, Colorado.Its spectacular Mesa Lab, modeled in part after Stonehenge by the architect I.M. Pei, looms in the foothills of the Rockies, the blocky, sand-colored towers looking like three-dimensional puzzle pieces cryptically arranged by ancient alien visitors. Just past a deer-crossing sign on the road leading to the Mesa Lab, an obviously newer sign reads danger: HIGH FIRE RISK.
"In the U.S., the last 12 months have been, by far, the warmest on record," Kevin Trenberth, the head of NCAR's Climate Analysis Section, tells me over lunch. "All of the Dust Bowl-era records from the 1930s have finally been vanquished." The last one to go was the July record: July of 1936 had been the country's warmest until 2012.
Trenberth is a trim New Zealander in his sixties. He's been living in the Boulder area for 28 years and very much looks the part, sporting cargo shorts and hiking sneakers as office attire. Trenberth spends his days synthesizing reams of climate data, and he says the evidence is stark. Earlier in the summer, he told the 'PBS NewsHour,' "You look out the window and you see climate change in action." He wasn't referring to individual weather events or naturally varying meteorological patterns, but rather to the sheer scale of the extremes. Offering a personal anecdote, Trenberth notes that a week or so before my visit, he'd been hiking around the Maroon Bells, a pair of peaks near Aspen, and, disturbingly, found no snow at all. "The heat from the sun was just coming down and heating the ground," he says. "Normally it would be, first, partly reflected by the snow, and second, all of the water – the melt from the snow – would be keeping things wet, and the heat from the sun would go into evaporating moisture. So there was nowhere for the heat to go other than to raise temperatures. These conditions set the stage throughout the Southwest for heat waves to develop, and the consequences have been wildfires."
Back in his cluttered office, Trenberth takes a seat in front of a wall of bookshelves groaning with scholarly journals. "I'm quite alarmed," Trenberth says, "mainly because when it comes to reducing emissions – to cutting down on the fundamental cause of the problem – there's been no progress since 2009." He connects this lack of progress to the massive pushback and disinformation campaign that followed Al Gore's 2006 film 'An Inconvenient Truth' and the Intergovernmental Panel on Climate Change's 2007 report, the largest and most detailed climate study ever undertaken, which called global warming "unequivocal." Trenberth was one of the lead authors of the IPCC report, and he and the IPCC shared a Nobel Peace Prize that year with Gore.
In the past, despite an overwhelming consensus on the reality of climate change, scientists were reluctant to forensically link any single short-term climactic variation – a particular heat wave or series of hurricanes – directly to warming trends. Weather patterns, after all, vary naturally, which is why things like the Dust Bowl could happen in Al Gore's father's time, long before greenhouse gases had become a threat. But the accrual of harrowing data has begun to eat away the science community's circumspection. This summer, a paper in the 'Bulletin of the American Meteorological Society' co-authored by climate scientists from the U.S. and the U.K. stated that "scientific thinking on this issue has moved on, and now it is widely accepted that attribution statements about individual weather or climate events are possible." In other words, the fact that all of the crazy weather you've been noticing the past few years happens to have been predicted by every credible climate-change model is not just a wild coincidence. The authors use a baseball analogy: If a player begins taking steroids and suddenly his number of home runs skyrockets by an average of 20 percent each season, it might remain impossible to say that any one particular home run was the sole result of the doping – other factors, such as the player's skill, the opposing pitcher, or the layout of a particular stadium, would of course come into play. But one could say that, because of the presence of the steroids, that particular hit was 20 percent more likely to occur.
Likewise with climate science. Droughts, heat waves, flooding, and tornadoes will always occur, but their frequency and severity are what makes climate change impossible to ignore. As one example, the authors cite the 2011 Texas drought, the worst single-year drought in the state's recorded history. While it was happening, meteorologists generally pointed to La Niña, a naturally occurring weather phenomenon over the Pacific Ocean that can affect rainfall worldwide. But in 2012, a statistical analysis by the authors of the BAMS report concluded that the Texas drought was 20 times more likely to occur today than during a comparable La Niña year in the 1960s, when greenhouse gases were much lower.
A shy, slightly awkward speaker, Trenberth rarely made eye contact during our nearly two-hour conversation, often staring down past his silver mustache at his folded hands, looking pensive, or as if he might suddenly launch into desperate prayer. He says there's little reason to realistically believe that the total warming of the globe will remain below 2 degrees Celsius (3.6 degrees F), the target set by the Copenhagen Accord – which has been described as "the bottomest of bottom lines."
"You continue to have some hope," he says. "But in order to address this internationally, the U.S. has to be a leader, and Congress has been absolutely hopeless on this whole issue. The environmental groups have hardly any money in comparison to the deniers." Trenberth's voice takes on a piquant edge for the first time during our conversation. "The vested interests are very clear in this game, and they're spending tens of millions of dollars every year," he concludes. "And most of them are on the denial side."