Torrential rains in South Africa's Kruger National Park have forced the emergency rescue of dozens of tourists and staff from the wildlife reserve, officials said Monday.

At least 15 tourists were airlifted to safety while several camps, roads and entrance gates to the giant park were closed.

Claims that global warming can be braked by dissolving huge quantities of rock in the sea to absorb carbon emissions are laden with flaws, a study published on Tuesday says.

The analysis is the latest scientific appraisal into geo-engineering, or techniques that are being promoted as quick fixes to the climate crisis.

U.S. President Barack Obama vowed to make climate change a priority as he was sworn in Monday to a second term, using some of his most forceful language yet despite uncertain political prospects.

In an inaugural address that kept largely to lofty but general prose, Obama zeroed in on the battle against climate change as a specific goal for his presidency's next four years after setbacks in his first mandate.

A U.S. spacecraft orbiting Mars has provided evidence of an ancient crater lake fed by groundwater, adding further support to theories that the Red Planet may once have hosted life, NASA said Sunday.

Spectrometer data from NASA's Mars Reconnaissance Orbiter (MRO) shows traces of carbonate and clay minerals usually formed in the presence of water at the bottom of the 1.4-mile (2.2-kilometer) deep McLaughlin Crater.

Opportunity, NASA's other Mars rover, has tooled around the red planet for so long it's easy to forget it's still alive.

Some 5,000 miles (8,000 kilometers) away from the limelight surrounding Curiosity's every move, Opportunity this week quietly embarks on its tenth year of exploration — a sweet milestone since it was only tasked to work for three months.

A mystery wave of cosmic radiation that smashed into Earth in the eighth century may have come from two black holes that collided, a study published on Monday says.

Clues for the strange event were unearthed last year by Japanese astrophysicist Fusa Miyake, who discovered a surge in carbon-14 -- an isotope that derives from high-energy radiation -- in the rings of ancient cedar trees.

Nepalese hunters have shot dead a leopard suspected of killing more than a dozen people in the past year in the country's remote western region, a police officer said on Friday.

A local police officer said a villager had locked the animal in his cowshed in the middle of the night and informed local hunters, who made a hole in the wall of the shed and shot the animal.

Delegations from some 140 countries have agreed to adopt a ground-breaking treaty limiting the use of health-hazardous mercury, the Swiss foreign ministry said Saturday.

The world's first legally binding treaty on mercury, reached after a week of thorny talks, will aim to reduce global emission levels of the toxic heavy metal also known as quicksilver, which poses risks to human health and the environment.

On the Internet, nobody knows you're a dog -- but it is getting increasingly easy for someone to figure it out.

As more and more of our personal data -- and those of the people we know and are related to -- gets posted online, the anonymity promised by the remove of a computer screen gets more and more elusive, according to a new study out Thursday in the U.S. journal "Science."

A weird marine creature that lived 500 million years ago at a time of explosive growth in Earth's biodiversity could be a forerunner of worms and molluscs, a study published on Thursday said.

Palaeontologists in China and Europe have taken a second look at fossils of a species called Cotyledion tylodes -- a small animal that, when it was identified in 1999, was at first thought to be a cnidarian, or part of a group of jellyfish-like species.