Defense Secretary Chuck Hagel said Friday that climate change is creating both new opportunities and challenges in the Arctic as warmer temperatures and melting ice transform the region.

Arctic ice is melting at an unprecedented rate, opening new sea lanes for commerce, exposing more areas for oil and gas drilling, and putting coastal communities at risk as oceans rise, Hagel said at the Halifax International Security Forum.

"Climate change, while not new to history, is new to the modern world," Hagel said. "It can significantly add to the global challenges of instability," such as poverty and hunger.

Hagel said the Obama administration would double down on efforts to maintain the Arctic region, which includes strengthening ties with Canada, Russia and other Arctic nations through international agreements.

The speech comes after the White House released a strategy for energy development in the Arctic this summer, which called for enhancing infrastructure for energy development.

The administration embarked on its plan following mishaps on Alaska's coast last year by Royal Dutch Shell. The oil giant was supposed to begin drilling in the Beaufort and Chukchi seas, but a series of technical delays forced it to pause the efforts. The company has recently said it hopes to resume drilling in the summer.

But policymakers around the world must be mindful of the impact burning fossil fuels will have on climate change and the Arctic, Hagel said.

The Pentagon has been looking at the nexus of energy and climate change for some time, Hagel noted. The federal government's biggest energy user, the Defense Department, is also its biggest consumer of renewable energy and plans to get 25 percent of its power from renewable sources by 2025.

In a sense, the Arctic's recent changes feed into each other — burning more fossil fuels as world energy demand rises releases more greenhouse gases, which warms the planet, which melts ice, which makes it possible for drillers to access hydrocarbons that were previously unavailable.

Nations must proceed with caution on that front, Hagel said, pointing to the destructive Typhoon Haiyan in the Philippines as an example of the intense and destructive storms scientists say could become more frequent with a warming planet.

Such disasters would put a strain on the Pentagon's resources in terms of providing humanitarian aid. And other potential effects of climate change — such as drought — could lead to desperately impoverished populations that become prime recruiting targets for extremist groups, the Defense Department has warned.

"The effects of climate change and new energy resources are far-reaching and unpredictable," Hagel said.