Trump envoy warns China's power move at sea is threat 'we cannot afford to ignore'

China is using control over global seas as a tool of "political coercion," the U.S. ambassador to the United Kingdom warned, as President Donald Trump is restating his interest in Greenland for that very same reason. China is seeking to turn ports, ships and supply chains into instruments of geopolitical leverage, U.S. Ambassador to the U.K. Warren Stephens warned in a statement to the International Maritime Organization Council (IMO). "I spoke about a challenge that we cannot afford to ignore: