Two Russian cosmonauts and an American astronaut on Tuesday landed back on Earth in Kazakhstan after a stay of more than half a year aboard the International Space Station.

Russians Oleg Kotov and Sergei Ryazansky and NASA astronaut Mike Hopkins touched down in their Soyuz capsule at 0324 GMT outside Dzhezkazgan in Kazakhstan, mission control said.

Worried scientists said Sunday they had found four new ozone-destroying gases in the atmosphere, most likely put there by humans in the last 50-odd years despite a ban on these dangerous compounds.

It is the first time since the 1990s that new substances damaging to Earth's stratospheric shield have been found, and others may be out there, they said.

Astronaut Koichi Wakata has become the first Japanese commander of the International Space Station, according to the country's space agency.

In a simple ceremony onboard the station, Wakata took over the facility's command from Russian predecessor Oleg Kotov, the Japan Aerospace Exploration Agency said late Sunday.

The European Union is making steady progress towards its 2020 renewable energy target, a key effort in curbing the greenhouse gas emissions blamed for global warming, official data showed Monday.

Renewables -- predominantly wind but including tidal and biomass sources as well -- accounted for 14.1 percent of the EU's energy consumption in 2012, up from 13 percent in 2011, the Eurostat statistics bureau said.

Australia has endured another "angry summer" with more than 150 temperature records smashed, a new report said Monday, with a warning that heatwaves and sweltering conditions will only get worse.

Among the records broken, Perth had its hottest night ever at 29.7 Celsius (85.4 Fahrenheit), Adelaide recorded its warmest February day (44.7 Celsius) while Sydney went through its driest summer in 27 years, the independent Climate Council watchdog said.

U.S. Secretary of State John Kerry has called on American ambassadors around the world to make the fight against climate change a top priority ahead of new U.N. talks next year.

In his first department-wide policy guidance statement since taking office a year ago, he told his 70,000 staff: "The environment has been one of the central causes of my life."

Astronomer Carl Sagan become Mr. Science for a generation after his 1980 series, "Cosmos," took audiences on a groundbreaking TV journey through the universe.

Astrophysicist Neil deGrasse Tyson, host of "Cosmos: A Spacetime Odyssey," the 21st-century edition debuting Sunday, has a head start with a Twitter following of 1.7 million that's just edged by the starry likes of Gwyneth Paltrow and Cee Lo Green.

South Africa's peace icon Desmond Tutu on Friday urged the United States to reject Canada's Keystone XL pipeline, saying the "carbon bomb" would upend the U.S. role fighting climate change.

The Nobel Prize-winning archbishop who fought apartheid led a letter to Secretary of State John Kerry urging him to reject the 1,179-mile (1,897-kilometer) pipeline, which would bring oil from the carbon-intense Alberta tar sands into the United States.

Negotiations over mackerel fishing quotas have fallen apart, Iceland said Thursday, extending a dispute dubbed "the mackerel war" that has been a thorny issue in the country's EU membership bid.

The European Union, Iceland, the Faroe Islands and Norway left a meeting in Edinburgh on Wednesday without reaching an agreement for 2014.

Campaigners warned Thursday of environmental threats from new oil-prospecting projects off Spain's Balearic and Canary Islands, two major tourist destinations.

Campaign group Ecologists in Action said in a report that 10 oil installations were operating off Spanish coasts and new oil-prospecting licences had been granted for the islands that draw millions of tourists every year.