SEWARD, Alaska — President Obama on Tuesday proposed speeding the acquisition and building of new Coast Guard icebreakers that can operate year round in the nation’s polar regions, part of an effort to close the gap between the United States and other nations, especially Russia, in a global competition to gain a foothold in the rapidly changing Arctic.

The president’s proposal, on the second day of a three-day trip to Alaska to highlight the consequences of climate change and call for a worldwide effort to address the issue, touches on one of its most profound effects. The retreat of Arctic sea ice has created opportunities for shipping, tourism, mineral exploration and fishing, but the rush of marine traffic that has followed is bringing new difficulties.

“Arctic ecosystems are among the most pristine and understudied in the world, meaning increased commercial activity comes with significant risks to the environment,” the White House said in a statement.

“The growth of human activity in the Arctic region will require highly engaged stewardship to maintain the open seas necessary for global commerce and scientific research, allow for search-and-rescue activities, and provide for regional peace and stability,” the statement said.