Hanging off a frozen waterfall might sound like a nightmare to many, but it's the winter weekend activity of choice for Don Serl. The 61-year-old ice climber has been front-pointing his way up ice-encrusted cliffs—establishing numerous routes in the process—for about 35 years.

As the author of West Coast Ice (Elaho Press, 2005), the preeminent guide to ice climbs in southwestern B.C., Serl knows route conditions can vary considerably from year to year. But he said he's been climbing long enough to be certain of two things: that climate change is a reality, and it's having an effect on the ice.

"It was clear more than a decade ago that we've warmed," Serl told the Georgia Straight, seated in the living room of his Vancouver home. "And that has changed the ice and the snow in the winter."

Ice climbing—which involves the use of specialized ice axes, spiked boot add-ons called crampons, and an arsenal of protective gear—isn't exactly a mainstream pursuit. Serl puts the number of people in the Vancouver area who climb at least one frozen waterfall or icy cliff face every year at between 50 and 100.

Serl recalls that when the first edition of West Coast Ice (written with Bruce Kay) was published in 1993, the Whistler-Pemberton and Hope-Yale corridors consistently offered ice suitable for climbing. Today, Shannon Falls, near Squamish, rarely freezes, and ice climbers often follow Highway 99 further inland to the Rambles, southwest of Lillooet, and Marble Canyon, which is between Lillooet and Cache Creek.

"I find it particularly ironic that now to go ice climbing, we have to drive our cars 500 kilometres to get to good ice on the weekends, instead of 150 kilometres or 100 kilometres," he said. "So we're contributing therefore to global warming, if you believe that shtick."

Serl has also noticed he's been making that first drive to Lillooet later than he did in years past. The typical ice-climbing season used to begin in early December, but now he doesn't even think about planning his first trip until New Year's.

According to Dan Moore, a professor of geography and forest resources management at UBC, the Lower Mainland has gotten warmer over the last century, though some decades have actually seen a decrease in the average annual temperature. Climate models anticipate milder winters in the southern Coast Mountains, and there will likely be fewer cold snaps, he said.

"The snow season is going to get shorter," Moore said. "That is, we're going to have rain later into the autumn before we start getting snow, and then the snowmelt is going to start earlier in the spring. That's pretty well accepted for the Pacific Northwest."

It's difficult to say whether the overall impact that climate change is having on ice climbing is positive or negative, said Drew Brayshaw, a Chilliwack resident who's been sticking ice tools into frozen waterfalls for 13 years. That's because, according to the PhD student in forest hydrology at UBC, the net effect of shifts in temperature, precipitation, and water flow is specific to each ice-climbing route. For instance, more ground water might improve a climb formed by water dripping down a cliff face, while a higher rate of stream flow can prevent a large waterfall from freezing.

"With ice climbs, it's a nonlinear effect because you're looking at temperature and water flow, and some climbs being better and some climbs being worse with more water," Brayshaw said from the Abbotsford office of Madrone Environmental Services, where he works as a geoscientist. "So, it's not a direct link."

According to Kate Sinclair, an ice climber and a PhD student in glaciology at the University of Calgary, slightly warmer temperatures lead to ice that's more plastic than brittle, which makes it easier to place ice tools and ice screws. On the other hand, she said, higher temperatures are resulting in greater avalanche risk and less stable waterfalls that are more likely to shear off.

Brayshaw, Moore, and Sinclair said they aren't aware of any scientists who are doing research on the impact of climate change on waterfall ice. Although that's likely because frozen waterfalls don't have substantial water-resource implications, Sinclair argued that the subject is worth investigating.

"Some of those big waterfalls in B.C. and Alberta are pretty iconic," she said from her office on the University of Calgary campus. "If we lose some of those, we're losing a pretty iconic feature of the mountain environment in the Canadian Rockies."

Serl noted that his climbing friends don't talk about climate change much, except to acknowledge that many routes don't form as often as they once did. When asked if he worries that southwestern B.C.'s ice climbs might eventually disappear, he laughed.

"I don't worry about it because I'm 61 years old," Serl said. "It's not going to affect me."