It was seen as one of the most distressing effects of climate change ever recorded: polar bears dying of exhaustion after being stranded between melting patches of Arctic sea ice.

But now the government scientist who first warned of the threat to polar bears in a warming Arctic has been suspended and his work put under official investigation for possible scientific misconduct.

Charles Monnett, a wildlife biologist, oversaw much of the scientific work for the government agency that has been examining drilling in the Arctic. He managed about $50m (£30.5m) in research projects.

Some question why Monnett, employed by the US Bureau of Ocean Energy Management, Regulation and Enforcement, has been suspended at this moment. The Obama administration has been accused of hounding the scientist so it can open up the fragile region to drilling by Shell and other big oil companies.

"You have to wonder: this is the guy in charge of all the science in the Arctic and he is being suspended just now as an arm of the interior department is getting ready to make its decision on offshore drilling in the Arctic seas," said Jeff Ruch, president of the group Public Employees for Environmental Responsibility. "This is a cautionary tale with a deeply chilling message for any federal scientist who dares to publish groundbreaking research on conditions in the Arctic."