Washington Capitals star Alex Ovechkin drives a Zamboni on Sept. 9, 2010 in New York as part of a video-game promotion. (Dan Steinberg/The Washington Post)

The commissioner of the National Hockey League has good reason to be concerned about global warming. “Our sport was born on frozen ponds and to this day relies on winter weather,” Gary Bettman said.

Two weeks before one of the most popular games on the league’s schedule, the outdoor Winter Classic, between the Washington Capitals and the Chicago Blackhawks at Nationals Park on New Year’s Day, Bettman announced that the NHL will wipe out its carbon footprint by the end of the season.

The league teamed up with Constellation Energy, Baltimore, which will conduct an energy-efficiency analysis starting in the next few days to determine whether the NHL can improve lighting and refrigerator motors that cool everything from the rinks to the drinks. Bettman said it will start at Verizon Center, where the Capitals play.

Bettman said the NHL is simply “taking an active role to preserve the environment and the roots of our game.” But Allen Hershkowitz, president of the Green Sports Alliance, said the potential impact goes far beyond that.

There’s a broader message when a sport with 30 teams and tens of millions of fans around the world acts as an aggressive environmental steward, Hershkowitz said.

Making sports more green is hardly a new idea — 600 representatives from college and professional teams met last year to discuss it, he said. But no other league has dared to measure its carbon footprint, let alone wipe it out.

Hershkowitz called Bettman’s announcement last week “the most important environmental initiative ever made by a sports league.” But the impact of pro hockey’s new environmental stewardship, like the accuracy of prognostications made about who will win and lose upcoming games, often wrongly, can’t yet be determined.

An evaluation of the league’s carbon footprint measured it at about 550,000 metric tons yearly. Seventy-five percent of it is electricity use, and the rest is generated by water use and the way teams travel.

Like other teams that share arenas, the Capitals are responsible for about a third of Verizon Center’s operations. Their strategy is to offset the carbon pollution the league emits with Renewable Energy Certificates from clean energy sources such as wind turbines and power generated from biomass.

Companies that produce clean energy sell the certificates, known as RECS, to companies that use dirty energy produced from coal to power their operations. Revenue from the purchase allows fledgling ­clean-energy sources to grow and compete with traditional power companies.

Whether this actually works is a matter of fierce debate, but the Environmental Protection Agency recognizes the credits.

Constellation’s chief executive, Joe Nigro, emphasized that the NHL is using credits because it’s “clearly committed to implementing energy-efficiency measures and cutting their carbon footprint.”

Moreover, he said, the league and Constellation are “hoping to encourage the hockey community to recycle” and otherwise conserve to protect the environment. The NHL, Nigro said, is “setting an example for the sports community and fans alike.”

Global reach

Hockey draws more than 8 million fans to its stadiums in the United States and Canada each year, and tens of millions of fans watch the fast-paced game on televisions in Europe, Asia and South America.

Hershkowitz said the league’s effort started six years ago when he was introduced to Bettman by a retired New York Rangers goalie, Michael Thomas Richter. Hershkowitz was on a mission set in motion by actor Robert Redford, a trustee of a conservation group where Hershkowitz worked at the time.

In a meeting at Redford’s home, Hershkowitz asked the actor for some advice. “How do we get our message out?” Redford answered in a sentence: “You have to do it through sports.” Professional sports in the United States and Canada draw about 200 million people to arenas, according to a 2008 report by the International Association of Sports Economists and the North American Association of Sports Economists.

The average ticket-holding hockey fan will see the first promotion of the league’s environmental program at the Winter Classic face-off.

The promotions at NHL stadiums will continue through the year, including the 2015 all-star game and the Stanley Cup Finals that crown the league champion.

NASCAR sets the pace

In championing the environment, though, hockey has a long way to go before it can overtake NASCAR, the National Association for Stock Car Auto Racing. Four years ago, it set out to lower pollution at noisy events where dozens of cars belch smoke and emit carbon by using huge amounts of gasoline.

Today, on its Web site, NASCAR claims to have “the largest recycling and environmental sustainability programs” of any American sports league. It also claims “the world’s largest solar-powered sports facility, a tree-planting program capturing 100 percent of the emissions produced by on-track racing, and the largest recycling program” with several corporate partners, including Coca-Cola and Coors.

Environmental stewardship in the nation’s most popular sport, football, is only beginning to take shape. Last year, Ohio State University ramped up its green initiative to reduce waste at Ohio Stadium in Columbus, where about a million fans visit each season.

The school sought to improve on a program that diverted 98 percent of trash from landfills during a game by extending it to an entire season.

The diversion rate for the 2012 season, 87 percent, was not enough, officials said. Twenty-three tons of trash went to landfills in 2012, compared with nearly 60 tons in 2010, according to a report by the Natural Resources Defense Council.

“We’re doing it to show it can be done,” said Jay Kasey, Ohio State’s senior vice president for administration and planning. “We want to get students and get faculty involved in our most visible activity, seven home football games a year.”

The number of ticket-buying NCAA football fans dwarfs hockey’s — 43 million in 2005, according to the sports economists.

But hockey is showing more heart when it comes to the environment, Hershkowitz said.

“They’re going to audit lighting, motors, heating, ventilation and everything else to see if it’s outdated,” he said. “It’s a complicated undertaking. Baseball doesn’t have this going on, the National Basketball Association doesn’t have this going on, the National Football League doesn’t have this.”