200 Reindeer Starved to Death. Experts Call It a Sign of Climate Change.

Across Arctic regions in Russia, northern Scandinavia and Greenland, wildfires are common in the summer. But this year, the number and intensity of the fires made for an unusual sight, burning huge sections of the Arctic and unleashing plumes of smoke visible from space. Mild spells have been a rare phenomenon in Svalbard, but they have increased in frequency in recent years, Ms. Pedersen said.

The effects of climate change are beginning to show, scientists say, with Ms. Pedersen and others warning of the effects on reindeer and other species in Svalbard as far back as 2013.

“Icing is predicted to become more frequent in the circumpolar Arctic and may, therefore, strongly affect terrestrial ecosystem characteristics,” they wrote in an article in Science.

More recently, in April, a study published in the Ecological Society of America’s Ecosphere journal found that the animals were increasingly isolated by the lack of sea ice on the one hand and the presence of ice-covered pastures, a result of rain during extreme warm spells, on the other.

Dozens, even hundreds, of the animals have been wiped out by various calamities over the years. In 2017, more than 100 reindeer were killed in a four-day period by freight trains rolling through Norway, prompting an outcry for the national railway to do more to protect the animals.

In 2016, more than 300 reindeer, huddled together in a storm, were killed by lightning on the Norwegian mainland, their carcasses left sprawled across a hillside on the Hardangervidda Mountain plateau. But that episode ended on a hopeful note.

The bodies of the animals became a laboratory, attracting scavengers from around the region that left in their feces an unusual concentration of plant seeds from the area, potentially spawning new plant diversity, Norwegian scientists said.