Researchers claim the moose population is threatened by higher temperatures in the spring and early summer that can upset their food supplies.
"We're not in any doubt," Bernt Erik Sæther of the Norwegian University of Science and Technology (NTNU) in Trondheim told newspaper Aftenposten. "The moose is extremely vulnerable to climate changes. An especially warm spring and early summer can have immediate consequences on the mooses' reproductive abilities."
That's because warmer temperatures will lead to earlier sprouting of the greenery on which moose calves feed. If it sprouts early, it may be too dry and fibrous by June, when the calves are born and start to feed.
That in turn will cause problems for the calves' digestive systems and leave them too thin to survive their first winter. "They body weight is like a barometer for climate change," Sæther said.
Researchers had thought Norwegian animals would generally be well-equipped to handle a warmer climate, and even benefit from less snow and ice. Instead, the opposite is true.
"We were very surprised by the findings, and that a warmer climate prompts large swings in the moose population," Sæther said. "But all our analyses point in the same direction."
The research on the moose population, which in general has increased in recent years, is part of the Norwegian Research Council's NORKLIMA program.
