On a bright and unseasonably warm March day, Auden Schendler, Aspen Skiing Company’s vice president of sustainability, and I trudge up the boot path to Highland Peak. Once we reach the 12,392-foot summit, we click into our bindings and ski down Highland Bowl, a 40-plus-degree pitch that drops 2,500 feet to the valley floor.

Schendler, who has skied the bowl more than 100 times during his 17-year career at the resort, drops in first. I give chase, bouncing turns through knee-deep snow. We traverse right toward a tree-lined chute to avoid an avalanche zone that has ripped out half of the bowl; warm temperatures, fog, and drizzle the day before caused water to percolate through the snowpack and undermine the integrity of the snow.

March is historically one of the best skiing months in the Rockies, but that wasn’t the case last season. I arrived in Aspen as a steady rain fell. Many resorts in Washington State had already closed for the season. In California, Lake Tahoe endured its fourth straight lousy winter. Aspen, Breckenridge, and other resorts in Colorado fared better because of their higher elevations, but even in the Rockies the snow was slushy by spring.

This is our new reality: On average, ski seasons are shorter and storms more difficult to predict. Fourteen of the warmest years on record have come in the past 15 years. And 2015 is on pace to be hotter still. Colorado has warmed by two degrees Fahrenheit over the past 30 years, and according to a 2014 report by the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences, climate models show temperatures could increase another two to six degrees by 2050. Artificial snowmaking has helped the ski industry—and also provided a false promise, because snowmaking only works when it’s cold.

Schendler and I stop at the bottom of the bowl after the long descent. Elated, we pause to observe the debris field left by the recent avalanche. House-size chunks of snow and ice are scattered across the landscape. Nobody died in the slide, but that hardly makes it less ominous. This avalanche, Schendler explains, is a signal of a sport in decline. “Climate scientists say we are going to see more events like this,” he says. “Warmer springs that drop rain instead of snow and make it hard to run our business.” »

Aspen Skiing Company has been one of the ski industry’s leaders on climate action since 1997, and Schendler is the resort’s outspoken climate czar. Nobody in the business has done more to sound the alarm and cajole resorts to confront climate change. He chairs Protect Our Winters, a global nonprofit devoted to climate activism, and he authored the book Getting Green Done, which is about the struggles of greening a big company. Schendler has testified before Congress, lectured at the Harvard Business School, and delivered countless climate talks. He has met with governors, senators, and congressmen and advised White House staff and the director of the Environmental Protection Agency about engaging skiers in the climate fight. Time magazine called him a “climate crusader” in 2006. “If anyone in America is standing up for winter,” says author and activist Bill McKibben, co-founder of the climate group 350.org, “it is Auden.”

Tall, muscular, and self-effacing, Schendler developed his environmental ethos as a child. He felt uneasy growing up in Weehawken, New Jersey, just across the Hudson River from Manhattan, and escaped to the countryside whenever he could, including annual trips to North Dakota and Montana to visit relatives. At 14, he joined an uncle on a 12-mile hike into the Montana wilderness; the trip provided his first glimpse of the grandiose beauty of the West. That same uncle, an old-school conservationist who worked for environmental foundations, inspired Schendler to pursue a similar career path.

After graduating from Bowdoin College in 1992 with a degree in biology and environmental studies, Schendler moved to Aspen. He worked for Outward Bound; with the government making homes more energy efficient; as a high school teacher; and as a ski instructor. Schendler joined Aspen Skiing Company in 1999 after a stint as a sustainability consultant at the Rocky Mountain Institute (RMI). RMI founder Amory Lovins was an early guru of operational greening—the idea that sustainability can equal profitability and that businesses will act out of rational self-interest to cut their energy use. Schendler put this philosophy to work at Aspen.

In 1999, Aspen was the first resort to inventory its carbon emissions and set reduction targets. The company then began investing in ground-source heating and cooling, replaced inefficient boilers with state-of-the-art heating and cooling systems, and installed high-performance windows and LED lights—simple but expensive projects that were years from becoming more common in the skiing industry and elsewhere. “We would do a project and then ask: Given what we know about climate, is this enough?” Schendler says. “Ski resorts use a ton of power. If you’re a resort trying to operate sustainably, you’ve got to address power.”

In 2008, the company spent $1.1 million to erect the ski industry’s largest solar array, built five high-efficiency LEED-certified buildings on the mountain, and constructed a hydroelectric plant that collects energy from spring snowmelt. At the same time, Aspen filed an amicus brief with the Supreme Court in support of the EPA’s right to regulate carbon emissions as a pollutant, the only ski resort to do so. By the end of the decade, Schendler had even proposed building a wind farm atop the Snowmass ski area, though the project never materialized because of the logistical challenges of erecting massive turbines in a sensitive alpine environment.

Early on, Schendler developed a reputation for being brutally honest when speaking about what many in the ski industry considered an uncomfortable topic. In 2007, a BusinessWeek story titled “Little Green Lies” quoted Schendler bemoaning “foot-dragging” colleagues who were making it difficult to green the resort. That same year he publicly criticized renewable energy credits—so-called carbon offsets—as useless in the fight to cut greenhouse gasses. At the time, Aspen was the ski industry’s largest buyer of these credits and was touting the offsets in its award-winning “Save Snow” advertising campaign. Schendler thinks he almost lost his job.

“Auden was ahead of everyone else in the ski industry by a decade, and he has the bumps and bruises to show for it,” says Squaw Valley Ski Holdings CEO Andy Wirth. Ski Magazine editor Greg Ditrinco says, “Auden’s strength has always been to be a bomb thrower and not to accept compromise.” A year after popularizing carbon offsets, Aspen pulled the plug on the energy credits. Schendler, who had initially encouraged Aspen to buy offsets, now calls them a cheap and easy way to greenwash your corporate image without doing the hard work of actually reducing energy consumption.

Aspen’s latest ambitious climate project launched in 2013. The company invested $5.5 million to collect rogue methane emissions from the Elk Creek coal mine in Somerset and burn that methane to make electricity. Coal mines are a major emitter of methane, a dangerous greenhouse gas. The project—one of the first and the largest of its kind in the United States—generates three megawatts of electricity annually, more than the amount used by Aspen’s four resorts over the course of each year.

Critics say it’s hypocritical for Aspen, a vacation town and home to millionaires, billionaires, and celebrities with multiple properties and private jets, to urge others to reduce their carbon emissions. Schendler acknowledges the irony but dismisses it as irrelevant finger-pointing. Aspen’s wealth and knowledge, he says, are precisely why the resort should lead. (Schendler says he has spent tens of thousands of dollars to turn his own 1950s house into an energy-efficient home.) “We have 1.4 million people who visit every year,” he says. “We are teaching them to get active on climate.”

Once resistant to Schendler’s message, others in the ski industry have started to catch up. Whistler Blackcomb in British Columbia recently built a large hydroelectric plant, and the tiny Berkshire East ski resort in Massachusetts constructed a wind turbine and solar farm that generates 100 percent of its energy. The National Ski Areas Association, the major industry trade group, now actively encourages ski areas to join its Climate Challenge program. “[Auden] was heralded as a lunatic by some of the old guard,” says Wirth, who is now implementing many of Schendler’s sustainability recommendations at his California resort. “But he had studied the science and done the research, and those views that were considered outrageous are now widely accepted.”

After 20 years on the front lines of corporate sustainability, Schendler has become frustrated with the slow pace of change. Though he’s accomplished many things at Aspen, these days he often wonders what he has actually achieved. The ski industry has made positive steps toward lowering its emissions, but resorts are far from eliminating their carbon footprints. And even if the entire ski industry did go carbon-neutral, it would do virtually nothing to slow climate change.

History has shown that big environmental improvements come after government acts: the Clean Air Act, the Clean Water Act, the Safe Drinking Water Act. In 2010, Congress killed the Waxman-Markey bill, known as the American Clean Energy and Security Act, which would have created a carbon-trading market and set national reduction targets. “There was a lot of soul-searching in the environmental community after the failure of Waxman-Markey,” Schendler says. One of the lessons, he says, was that the bill had no loud public support—there was no citizen action pushing Congress. “We need to create a social movement if we want to force big change,” Schendler says. “The only hope for the climate is an engaged citizenry.”

Schendler believes skiers must be part of jump-starting that movement. Snow-based recreation contributes $67 billion annually to the nation’s economy; 20 million Americans ski; and the industry can have political influence. “We as citizens did it with labor rights, civil rights, women’s rights, marriage equality. Those are all social movements where people changed the direction of our country by speaking up and acting up,” Schendler says. “That’s what we need on climate.”

On my last day in Aspen this past spring, I met with Schendler to ski Highland Bowl once more. It was a sunny Saturday, and he brought his 11-year-old daughter and eight-year-old son. As a father, Schendler, 45, worries about whether there will be any snow here in 2050, when his daughter is 46. Nobody can say for sure. By 2100, scientists say sagebrush could be growing atop Highland Peak in the winter and Aspen could be six degrees Fahrenheit warmer—which would make it similar to the current average annual temperature in Los Alamos, New Mexico.

Despite this grim prognosis, climate models show that Aspen and other mountains in Colorado could be among the last of the great American ski resorts to prosper. As operations in lower-elevation mountains on the East and West coasts struggle, the high peaks of Colorado and the Rocky Mountains likely will be among the snowiest mountains in the Lower 48. However, Schendler says, “if we see four degrees Celsius warming (7.2 degrees Fahrenheit) by 2100 as many scientists predict, or, God forbid, seven to 10 degrees as some climate models predict, there are going to be so many huge societal, economic, and humanitarian crises that worrying about skiing will be silly.”

We reach the summit of Highland Peak and pause to take in the views of snow-covered mountains. It is an inspirational setting, and Schendler remains optimistic even as he discusses the difficult future facing the ski industry. Renewable energy production is ramping up and coal power is dying in the United States. The pope is a climate hawk. President Barack Obama’s administration took bold action in August by releasing its Clean Power Plan—the single largest U.S. government initiative to date in the effort to reduce carbon emissions. International climate talks resume in Paris this month, with hope for a binding international treaty. Schendler has no plans to attend (why burn a lot of carbon to fly there when you can get more done at home, he says). Instead, he has worked to drive ski industry support for the Clean Power Plan and collect signatures for a petition urging the Obama administration to push for strong action in Paris.

The social movement also may be growing. An estimated 400,000 people showed up for the People’s Climate March in New York City in 2014. Schendler was among the skiers there that day. “Skiers have to fight,” he says. “We have to be part of the solution.” But for the moment, Highland Bowl awaits. We click in and drop in. Again, we traverse right to safely avoid the recent avalanche zone. On the far side of the slide, amid a patch of tree-lined chutes, the snow is soft and plentiful.