The US coastguard’s heavy-duty icebreaker Polar Sea is the only one remaining in the fleet. Photograph: Rob Rothway/US Coast Guard/Reuters

United States president Barack Obama yesterday proposed a faster timetable for buying a new heavy icebreaker for the US Arctic, where quickly melting (...)

President Barack Obama will officially restore Denali as the name of North America’s tallest mountain, ending a 40-year battle over what to call the peak that has been known as Mount McKinley. Photograph: National Park Service/Tim Rains/Reuters

President Barack Obama on Monday will officially restore Denali as the name of North America’s tallest mountain, siding with the state of Alaska in en(...)

Ashley Madison founder Noel Biderman. Photograph: Bobby Yip/Reuters

Emails sent by the founder of infidelity website AshleyMadison.com appear to have been exposed in a second, larger release of data stolen from its (...)

US  presidential candidate Donald Trump at Manhattan Supreme Court in New York on Monday, where he appeared for jurty duty. Trump’s  hard line on immigration has driven rivals to match his biting anti-immigrant language. Photograph: Lucas Jackson/Reuters

Republicans thought they had learned a lesson after 2012: Turning off Latino voters ensures defeat in the general election. But as the disruptive US p(...)

Demonstrators hold signs during a protest in Sao Paulo, Brazil, during a protest in Sao Paulo, Brazil, on Sunday. Nationwide street protests against Brazilian president Dilma Rousseff are keeping pressure on the government. Photograph: Patricia Monteiro/Bloomberg 1:27

Hundreds of thousands of demonstrators returned to the streets in dozens of Brazilian cities on Sunday to call for the impeachment of president Dilma(...)

 A dinghy overcrowded with Syrian migrants approaches a beach on the Greek island of Kos this week after crossing a part of the Aegean sea from Turkey to Greece. Photograph: Milos Bicanski/Getty Images

The appalling realities of mass migration from Syria’s civil war have been highlighted in images from Kos, where thousands of refugees are now arrivin(...)

Democratic Senator Chuck Schumer, who has said he will oppose the nuclear deal between Iran and world powers. Photograph: Andrew Harrer/Bloomberg

US president Barack Obama’s hopes of preserving the nuclear deal between Iran and world powers have been dealt a setback with the announcement by C(...)

Barack Obama: said the deal with Iran was the “strongest non-proliferation agreement ever signed”. Photograph: Jonathan Ernst/Reuters

Barack Obama criticised opponents of the nuclear agreement with Iran yesterday, accusing them of using many of the same arguments that had been made t(...)

US President Barack Obama delivers remarks on a nuclear deal with Iran at American University in Washington August 5, 2015. “I know it’s easy to play on people’s fears, to magnify threats... but none of these arguments hold up,” he said. Photograph: Reuters

US president Barack Obama warned on Wednesday that a block of the Iran nuclear deal by US politicians would accelerate Iran’s path to a nuclear weapon(...)

US president Barack Obama on Monday unveiled the final version of his Clean Power Plan, a set of Environmental Protection Agency regulations that, if implemented, would represent the strongest action ever taken by the United States to combat climate change. Photograph: Zach Gibson/The New York Times.

US president Barack Obama on Monday unveiled the final version of his Clean Power Plan, a set of Environmental Protection Agency regulations that, if (...)