While climate change is posing a global threat by melting polar ice, it is creating an ice crisis of a different kind in Japan.

At risk is the tradition of making ice under natural conditions. As weather patterns have changed in ice-making regions, it has become difficult to ensure the sensitive conditions necessary for producing the crystal-clear ice favored by aficionados of Japan’s favorite summertime delicacy — kakigori, shaved ice with flavored syrup.

Although this crisis may not be an existential problem for mankind, it is nonetheless a chilling reminder of the looming shadow of climate change. Global warming, the most prominent marker of climate change, is causing ice caps in the Arctic and Antarctic to melt, a phenomenon that, if unchecked, will raise sea levels and flood coastal areas.

“It was rainy throughout December,” Yuichiro Yamamoto said with a sigh of frustration in early February. “I wonder how many times our ice was ruined.”

Yamamoto, 64, runs a natural ice factory in Nikko, Tochigi Prefecture.

Of course, any ice, be it from the bosom of Mother Nature or from a refrigerator in the kitchen, may be shaved and slathered with syrup. But pristine natural ice carefully nurtured by artisans like Yamamoto is presumably de rigueur, particularly for a clientele in posh places like Ginza in Tokyo and Gion in Kyoto, the main destinations of ice from Yamamoto’s factory.

Yamamoto makes ice in a pond similar in size to a typical school pool. Machine cutters are used to divide the naturally formed ice into convenient-sized blocks, around 60 cm long, 45 cm wide and 15 cm thick. The ice blocks are kept in a wooden storage shed until shipment.

The tradition of making natural ice has a long history in Nikko, located deep in a mountainous area in the north of the Kanto region, where winter cold is severe but there is little snowfall.

Snow and rain are a curse for ice factories. For the pond water to be transformed into high-quality natural ice, it is essential that it freeze tight in a slow process that requires a temperature range of minus 5-8 Celsius. Rainfall and snowfall wreck this process by raising the temperature of the ice surface, causing cracks and reducing transparency.

“This year, we managed to secure a sufficient amount (of ice) again, but the quality of some ice was only 70 percent good,” Yamamoto said.

Ryoji Asami, who manages an ice factory in Nagatoro, Saitama Prefecture, is also feeling the heat of climate change. “We have to deal with nature. We are lucky to have been able to continue running our factory until now,” Asami said.

Asami, 35, has been keeping the records of the state of his factory’s ice pond as well as temperature and other weather conditions every morning in winter, December to March, as his father did before him. That the weather pattern is not what it used to be is clear from the four decades of records accumulated by Asami and his father.

“The climate around here has completely changed,” Asami said.