Hockey has glove saves, skate saves and stick saves. The National Hockey League (NHL) is trying to make an even bolder save. The NHL wants to save the planet.This may sound like a joke. What does hockey have to do with taking care of the environment? Well, for one, the game is played on ice. Frozen ponds, where so many of the league’s players learned to skate, are in trouble. In coming decades, the average length of the skating season may shrink by a third in eastern Canada. It may shrink by 20 percent in western Canada.That’s according to information in the NHL’s 2018 report on sustainability. Sustainability means helping to keep the environment healthy. The report was released March 28. It assesses the league’s environmental effect and effort to fight climate change.NHL Takes An Environmental StanceAllen Hershkowitz leads the Board of Sport and Sustainability International. His group brings people in sports together. They fight climate change and dangers to the environment. Hershkowitz credits the NHL for using the term climate change at a time when President Donald Trump and others in government do not seem worried about environmental challenges.Omar Mitchell is an NHL vice president. He said the league works to protect the environment because it "is the right thing to do.”Report: Humans Are Main Cause Of Climate ChangeGovernment reports from 2017 said humans are the main cause of a big change. There has been a rise in the world's temperatures. The rise has led to the warmest period in the history of people. Reports say average temperatures have increased 1.8 degrees Fahrenheit over the past 115 years.That period includes the rise of hockey. The NHL celebrated its 100th anniversary in 2017. It wants to be around for at least 100 more years.A survey about the environment was conducted last year. In it, 59 percent of Americans agreed that protecting the environment is very important. In addition, 56 percent said protecting the environment should be more important than economic growth. In other words, we should protect the environment even if this makes it harder for businesses to make money.Reducing The Sport's Carbon FootprintThe NHL’s report is voluntary. In it, the league takes a hard look at its carbon footprint. A person or group's carbon footprint means the amount of greenhouse gases their activities released. Nearly all scientists agree that greenhouse gases like carbon dioxide (CO2) are causing climate change.Mitchell says most of the NHL's carbon footprint comes from making the ice for the rink. The league is trying to find ways to lower how much power is needed for this.The league calls March its “NHL Green” month. The NHL Greener Rinks Initiative program was launched in 2016. It evaluates the environmental impact of about 4,800 indoor rinks in North America.“If we can influence the 76 million fans who watch our sport, that’s where you’re going to have real change,” says Mitchell.Fans Urged To Think Green, Donate Used EquipmentOne section of the NHL’s report is called “Play It Forward.” It asks fans to use some of the NHL’s environmental practices. The NHL and the Bonneville Environmental Foundation have a program called Gallons for Goals. They donate 1,000 gallons of water to rivers with critically low flow for every goal scored in the season. Meanwhile, the league asks fans to use an online water calculator. This helps fans measure their own water use.Fans donated 4,245 pounds of used equipment during the league’s 100th anniversary year, including helmets, skates and pads. The idea was to recycle the equipment and keep it out of landfills.Watching Effects Of Climate Change On Outdoor Rinks, PondsThe NHL’s sustainability report talks about RinkWatch. The program encourages citizens to check on outdoor rinks and ponds in their neighborhoods in Canada. More than 1,400 rinks and ponds are being tracked. This is helping scientists study the effects of climate change.“A lot of NHL players grew up playing hockey outdoors," says Kim Davis, an NHL leader. She said it's important that future players have frozen ponds where they can learn to skate too.