Beyond a clear-cut in Quebec's far north -- marked by a sign that reads "the road of destruction ends here" -- aboriginal Canadians are fighting for an ancient forest and their traditional hunting rights.

Canada's boreal forest is the largest intact forest in the world, comprising one-third of the forest circling the North Pole above the 50th parallel.

You can learn a lot from a tooth.

Molars taken from skeletons unearthed by work on a new London railway line are revealing secrets of the medieval Black Death — and of its victims.

Soaring carbon emissions will amplify the risk of conflict, hunger, floods and migration this century, the U.N.'s expert panel said Monday in a landmark report on the impact of climate change.

Left unchecked, greenhouse gas emissions may cost trillions of dollars in damage to property and ecosystems, and in bills for shoring up climate defenses, it said, adding the impact would increase with every additional degree that temperatures rise.

Lights went off in thousands of cities and towns across the world on Saturday for the annual Earth Hour campaign, which is aiming to raise money via the Internet for local environmental projects.

The Singapore-based campaign by conservation group WWF was boosted by Hollywood star power, with "The Amazing Spiderman-2" stars Andrew Garfield, Emma Stone and Jamie Foxx leading ceremonies at the city-state's Marina Bay district.

Astronauts' hearts grow rounder while they are in space, suggesting that spending lots of time in microgravity could lead to heart problems, according to U.S. research on Saturday.

That could mean trouble for people who want to embark on long-term missions to Mars.

Sydney's Opera House and Harbor Bridge plunged into darkness Saturday for the Earth Hour environmental campaign, among the first landmarks around the world to dim their lights for the event.

Lights will go out in some 7,000 cities and towns from New York to New Zealand for Earth Hour which this year aims to raise hundreds of thousands of dollars for green projects.

Scientists have created the first man-made chromosome for a complex-celled organism -- a feat hailed Friday as a big step towards acquiring the controversial ability to redesign plants or animals.

A synthetic chromosome was inserted into a brewer's yeast cell, which functioned as normal -- the key test of success, the international team reported in the journal Science.

The spotting of ocean debris by satellites during the search for the lost Malaysian airliner has drawn attention to those orbiting platforms. A primer on what's in orbit, with help from Nicholas Johnson, who retired Thursday as NASA's chief scientist for orbital debris:

HOW MANY SATELLITES ARE UP THERE?

It looks like a giant sandbox — except the sand has a reddish tint and the "toys" on display are very expensive prototypes designed to withstand the rigors of landing on Mars.

The European Mars rover unveiled Thursday at a "Mars Yard" testing ground in Britain is designed to drill beneath the surface of the Red Planet searching for signs of life. It's been dubbed 'Bryan' by its creators — earlier versions were named Bridget (clad in gold material that makes it look like a garish dune buggy) and Bruno.

A Moscow-backed spacecraft carrying two Russians and a U.S. astronaut on Friday docked successfully at the International Space Station after a technical hitch caused an unprecedented two-day delay.

The Soyuz TMA-12M, carrying Russia's Alexander Skvortsov and Oleg Artemyev and NASA's Steve Swanson, docked at 3:53 am Moscow time (1153 GMT Thursday), Russia's mission control said.