Climate change and the danger of nuclear war pose an ever-growing threat to civilization and are bringing the world closer to doomsday, a group of prominent scientists and Nobel laureates said Thursday.

"It is now three minutes to midnight," said Kennette Benedict, executive director of the Bulletin of the Atomic Scientists, as the group moved its symbolic "Doomsday Clock" two minutes forward.

The hand structure of early human ancestors who lived 3.2 million years ago suggests they had the ability to grasp and use tools, even if they hadn't invented them yet, anthropologists said Thursday.

Until now, Australopithecus africanus, which lived two to three million years ago in what is now South Africa, were not believed to have made tools -- the first evidence of which dates back to 2.6 million years ago -- but their hands suggest otherwise, according to a study in the journal Science.

San Francisco Bay Area officials have begun laboratory tests and necropsies on dead seabirds found coated with a mysterious substance that looks and feels like dirty rubber cement.

About 200 dead birds have been found along the bay's shorelines, said Andrew Hughan, spokesman for the California Department of Fish and Wildlife.

An asteroid up to 1,800 feet across is headed Earth's way. But don't worry: It will miss us by 745,000 miles, about three times the distance between Earth and the moon.

Still, that's close for such a large rock.

The skies of China's notoriously smog-filled cities saw a marginal amelioration last year, according to figures released by Greenpeace Thursday, but pollution remained far above national and international standards.

China's cities are often hit by heavy pollution, blamed on coal-burning by power stations and industry, as well as vehicle use, and it has become a major source of discontent with the ruling Communist Party.

More than 100 artists on seven continents will take part in a "Live Earth" global concert on June 18 to demand action on climate change, former U.S. vice president Al Gore said Wednesday.

"We are going to have one event all over the world on all seven continents," he announced at the World Economic Forum in Davos.

A volcanic eruption in Tonga has created a new island — although scientists say it could soon disappear.

The volcano has been erupting for a month in the ocean about 65 kilometers (40 miles) northwest of the capital, Nuku'alofa. Last week it disrupted international air travel to the Pacific archipelago for several days.

The private space exploration firm SpaceX said Tuesday it had secured a $1 billion investment that could help founder Elon Musk's plan to build a satellite Internet network.

The latest round of funding comes from Google and the financial firm Fidelity, which will own some 10 percent of the company.

Precious scrolls blackened by the eruption of the Vesuvius volcano in AD 79 may become readable again, thanks to 21st century technology, scientists said on Tuesday.

Hundreds of papyrus scrolls believed to have been authored by Greek philosophers were found in the Roman town of Herculaneum, which was hit in the same eruption that destroyed the town of Pompeii.

The Solar System has at least two more planets waiting to be discovered beyond the orbit of Pluto, Spanish and British astronomers say.

The official list of planets in our star system runs to eight, with gas giant Neptune the outermost.