Melting permafrost that has cut short drilling in Alaska is also an obstacle to development in the shallow waters of the Russian Arctic, an audience at the Deep Offshore Technology conference in Stavanger heard on Thursday.

“You could try thermal casing or some other type of technology, but our knowledge of the seabed conditions is poor offshore the Arctic,” said Professor Anatoly Zolotukhin, a Statoil technical director for Russia, answering a question from an FMC Subsea delegate.

Zolotukhin, who teaches Norwegians and Russians the strictures of arctic technological challenges, also warned of other phenomena that climate change would bring about. One obvious effect are “the nice round lakes” that dot the tundra at old wells where cement casing has dropped through the permafrost and into the underlying swamp, a process that could be a factor offshore as well.

Global warming will likely increase the number and size of icebergs roaming arctic waters and able to scour away seabed installations. The professor said icebergs of 200,000 tonnes take several hours to tie-up and tow away and that sometimes the operation fails.

“Bigger bergs are 10-million-tonnes,” the professor said, speaking in perfect English. “Forget about towing that away.”

He suggested the giant Shtokman gas-field development could also face the challenge of an unstable seabed, plus temperatures as low as minus 40 degrees Celsius (not the -73 degrees of deepest Siberia).

“Do we have the right material? The answer is maybe,” he said.

All pipelines, he warned, would have to be “stress-based designs” that withstand shifting ice, permafrost and gouging bergs.