WATERLOO, Ontario — Jack Williams and his sister, Cara, sat in their kitchen watching their backyard rink melt.
“Dad calls it a big birdbath,’’ said Jack, who is 12.
Their father, Ian, lovingly rebuilds the rink every year. He shovels it clear after each snowfall, and occasionally finishes the 24-foot-by-48-foot surface with hot water. He frets over every leaf that lands on the ice: they warm with the sunlight and create mini-craters.
A rink like the Williamses’ used to offer good skating in this part of Canada from early December into March. But on this late February afternoon, the temperature outside was 55 degrees and rain had fallen steadily all day. The week before, 2 feet of snow — mostly gone now, with leftover mounds seeping foggy wisps into the saturated air — blanketed the ground.
Williams makes a rink every year because he had one across the street when he was a child. Long seasons on the ice helped him get good enough to play college hockey.
“You want your kids to experience a little of the goodness you had when you were growing up,’’ he said. He has seen Jack and Cara’s skills improve, and he enjoys when their friends come over to skate and play hockey or just goof around on the ice.
But Williams is finding it hard to maintain the ice in a warming world. “There’s a huge difference between when I grew up and was skating outside, and the last five years of skating out here,’’ he said. “Will my kids, my grandkids, be able to play in an outdoor rink? Probably not. It might be a dying tradition.’’
That day last month happened to be the warmest Feb. 20 in recorded history for Waterloo. The previous record was set in 2016, noted Robert McLeman, an environmental scientist at Wilfrid Laurier University here. “You’re here on a landmark day,’’ he told me. “And if you come back in a couple of years, you’ll probably have another one.’’
An hour away in Brantford — hometown of Wayne Gretzky, who learned to skate on a backyard rink made by his father — a huge flood forced thousands of residents to evacuate their homes.
Climate change is warming the Northern Hemisphere rapidly, largely because of the greenhouse gases that humans have put into the atmosphere since the beginning of the industrial age.
McLeman, with Colin Robertson, both associate professors of geography at Wilfrid Laurier, created Rink Watch, a citizen science project that has enlisted more than 1,500 backyard rink owners like Williams — about 80 percent of them in Canada — to report skating conditions daily.
Climate change does not mean the immediate end of cold weather, as recent nor’easters have shown, but it is putting a squeeze on outdoor skating, a deep part of this country’s cultural identity. Irregular freezing weather is not enough for a good outdoor rink; consistency is key.
At least five days of hard freezing, 14 degrees Fahrenheit or lower, is essential to start a rink, McLeman said. And 23 degrees or lower is required from then on to maintain a good surface.
The National Hockey League expressed concern about the warming trend as part of its first sustainability report, issued in 2014. The league commissioner, Gary Bettman, wrote that “Our sport can trace its roots to frozen freshwater ponds, to cold climates.’’
