With 160 countries having signed on, the Obama administration is making a new push for U.S. Senate approval. Refusal puts the U.S. at risk of getting frozen out of its share of the spoils.Arguing for its ratification at a recent Senate hearing, Clinton said the treaty would offer the U.S. oil and gas rights some 600 miles into the Arctic. She said American companies were "equipped and ready to engage in deep seabed mining," but needed to join the treaty to take exploit oil, gas and mineral reserves. On Saturday, in the eight-nation Arctic Council's home city, she stressed that the international agreement "sets down the rules of the road that protect freedom of navigation and provides maritime security, serving the interest of every nation that relies on sea lanes for commerce and trade." The Arctic's warming is occurring at least twice as fast as anywhere else, threatening to raise sea levels by up to 5 feet this century and possibly causing a 25 percent jump in mercury emissions over the next decade. The changes could threaten polar bears, whales, seals and indigenous communities hunting those animals for food, not to mention islands and low-lying areas much farther away, from Florida to Bangladesh. The changing climate also is changing the realm of what is possible from transportation to tourism, with the summer ice melting away by more than 17,000 square miles each year. During the most temperate days last year, only one-fifth of the Arctic Circle was ice-covered. Little of the ice has been frozen longer than two years, which is harder for icebreakers to cut through. Europeans see new shipping routes to China that, at least in the warmth and sunlight of summer, are 40 percent faster than traveling through the Indian Ocean, the Suez Canal and the Mediterranean Sea. A northwest passage between Greenland and Canada could significantly speed cargo traveling between the Dutch shipping hub of Rotterdam and ports in California.