A Texas hunting club said Friday it aims to raise up to a million dollars for endangered black rhinoceroses by auctioning off a permit to kill one in Namibia.

"First and foremost, this is about saving the black rhino," said Ben Carter, executive director of the Dallas Safari Club, which is hosting the auction early next year.

A Greenpeace activist Saturday staged a two-hour protest in a tent suspended from the second floor of the Eiffel Tower against Russia's detention of 30 members of the environmental lobby group.

The activist also unveiled a banner with the slogans "Free the Arctic 30" and "Militants in prison, climate in danger", forcing authorities to close the French monument to tourists in the morning.

Former U.S. vice president Al Gore on Thursday urged President Barack Obama to block the Keystone XL oil pipeline from Canada, likening the carbon-intense project to drug addiction.

Gore, who has championed action against climate change since his razor-thin loss for the White House in 2000, praised Obama's general views on climate change but said his fellow Democrat faced a key test on the proposed project.

Scientists in China said Thursday they had designed a "smart" window that can both save and generate energy, and may ultimately reduce heating and cooling costs for buildings.

While allowing us to feel close to the outside world, windows cause heat to escape from buildings in winter and let the Sun's unwanted rays enter in summer.

Thanks to evolution, hungry desert-dwelling wild mice can shrug off the pain of scorpions' stings in order to gobble them up for a meal, scientists said Thursday.

This rare survival tactic has helped grasshopper mice use the venom of the Arizona bark scorpion, found in the southwestern United States and Mexico, to numb its excruciating sting.

Scientists in China said Thursday they had designed a "smart" window that can both save and generate energy, and may ultimately reduce heating and cooling costs for buildings.

While allowing us to feel close to the outside world, windows cause heat to escape from buildings in winter and let the Sun's unwanted rays enter in summer.

The amount of harmful greenhouse gas pollution spewed into the atmosphere by large U.S. power plants has declined 10 percent since 2010, the U.S. government said Wednesday.

The results came from the third year of carbon pollution emissions data that the Environmental Protection Agency collects from nearly 8,000 facilities including power plants, oil refineries and steel mills.

Japanese scientists readying to blast a crater in an asteroid to find out what it is made of said Wednesday they have successfully tested their new space cannon.

The Japan Aerospace Exploration Agency (JAXA) said the huge weapon would fire a metal bullet at the surface of asteroid 1999JU3 some time in 2018.

British engineers said Wednesday they had taken inspiration from dolphins for a new type of radar device that could easily track miners trapped underground or skiers buried in an avalanche.

The device, like dolphins, sends out two pulses in quick succession to allow for a targeted search for semiconductor devices, cancelling any background "noise", the team wrote in the journal Proceedings of the Royal Society A: Mathematical and Physical Sciences.

A bout of choking smog that brought life to a standstill in a far northeast Chinese city for three days has dissipated, with flights resuming and students returning to school Wednesday.

The heavy pollution, which drew national and international headlines, was largely due to coal-fired heating and the burning of large amounts of straw as winter approaches, local environmental officials in the city of Harbin have said.