A climate scientist on Wednesday said he was being threatened with the sack for refusing to fly back to Germany from a research trip in Papua New Guinea.
Gianluca Grimalda, a senior researcher at the Kiel Institute for the World Economy (IfW Kiel), has spent six months investigating the social effects of climate change in the Pacific island country.
Grimalda made most of the outward trip to Papua New Guinea by land and sea, taking 35 days to travel around 16,000 kilometres.
He wished to return entirely by cargo ships, ferries, trains and buses, he said in a statement shared by the campaign group Scientist Rebellion.
But the IfW Kiel is allegedly insisting approval for his trip ran out on September 10 and he must return immediately by plane.
"I am now faced with this dilemma: keeping my job while reneging on my principles, or losing my job while holding on to my principles," Grimalda said.
"I won't board that plane... To me, catching a plane while a lower-carbon alternative exists is immoral," he said.
According to Grimalda, his research trip had to be extended by 45 days due to security threats and logistical obstacles.
"There is nothing... that requires my presence in Kiel. I don't teach, I don't have to attend seminars or other meetings," he said.
"There is nothing I must do in Kiel that I can't do on a ship or a train while travelling. They know that I am actually very productive when I travel."
He also said he had offered to take unpaid leave.
A spokesman for the IfW Kiel said the institute would not comment on internal personnel matters.
"The institute supports its employees in travelling in a climate-friendly manner when on business trips," the spokesman said.