France, July 2 -- When NATO leaders met last week, they repeated familiar warnings about Russia, China and Iran. But one threat did not make the main agenda - climate change. A new study shows rising temperatures could quietly change how submarines are hunted under the sea.

The summit followed a familiar script. Between calls for bigger defence budgets pushed by US President Donald Trump and talks on threats from Russia and Iran, climate change did not make the priority list.

But military and civilian researchers working with NATO say warming seas could deeply change underwater warfare.

In 1989, The Hunt for Red October hit cinemas. Based on Tom Clancy's novel, the film told the story of a nearly invisible Soviet nuclear submarine trac...