The U.S. defended its track record on fighting climate change on Monday at U.N. talks, saying it's making "enormous" efforts to slow global warming and help the poor nations most affected by it.

Other countries have accused Washington of hampering the climate talks ever since the Bush administration abandoned the Kyoto Protocol, the 1997 treaty limiting emissions of heat-trapping gases by industrialized countries. As negotiators met for a two-week session in oil and gas-rich Qatar, U.S. delegate Jonathan Pershing suggested America deserves more credit.

An army of rice-grain-sized beetles, attracted by warming weather, has moved into Canada's western forests, where its tree massacre is causing the mercury to rise yet further, a study said Sunday.

The voracious horde of mountain pine beetles has invaded about 170,000 square kilometers (65,000 square miles) -- a fifth of the forest area of British Columbia, Canada's western-most province, a research team wrote in the journal Nature Geoscience.

Rising acidity is eating away the shells of tiny snails, known as "sea butterflies", that live in the seas around Antarctica, leaving them vulnerable to predators and disease, scientists said Sunday.

The study presents rare evidence of living creatures suffering the results of ocean acidification caused by rising carbon dioxide levels from fossil fuel burning, the British Antarctic Survey said in a statement.

Norwegian explorer Roald Amundsen's three-mast ship Maud, long abandoned in the Canadian Arctic ice, will be salvaged and repatriated mid-2013, a Norwegian group announced Sunday.

The group, which plans to return the old polarship to Norway to be the centerpiece of a new museum, is this week in Cambridge Bay in Canada's far north filming and photographing the shipwreck trapped in ice.

Nearly 200 nations launched a fresh round of United Nations climate talks in Doha on Monday faced with appeals for urgency in their efforts to reduce Earth-warming greenhouse gas emissions.

The 18th U.N. climate conference comes amid a welter of scientific warnings that extreme weather events like super-storm Sandy will become commonplace if mitigation efforts fail.

During a year with a monster storm and scorching heat waves, Americans have experienced the kind of freakish weather that many scientists say will occur more often on a warming planet.

And as a re-elected president talks about global warming again, climate activists are cautiously optimistic that the U.S. will be more than a disinterested bystander when the U.N. climate talks resume Monday with a two-week conference in Qatar.

Environmentalists and nationalists held opposing rallies over the issue of Japan's dolphin and whale hunts in a rare showdown in central Tokyo on Saturday, leading to angry scenes.

About 50 anti-whaling activists gathered at a park in the Shibuya shopping district with banners bearing slogans such as "Stop the cruel dolphin hunt!" while across the street about 30 nationalists shouted "Get out of Japan!"

Nearly 200 nations gather in Doha from Monday for a new round of climate talks as a rush of reports warn extreme weather events like superstorm Sandy may become commonplace if mitigation efforts fail.

Negotiators will converge in the Qatari capital for two weeks under the U.N. banner to review commitments to cutting climate-altering greenhouse gas emissions.

Estonia's thriving brown bear population has spread nationwide after hunters eased up in their traditional territory, an expert in the Baltic state said Friday.

"Bears have been able to expand their living range from central Estonia through to the western regions on the Baltic Sea, mainly because hunters have been avoiding killing mother bears in central Estonia," Peep Mannil, head of wildlife monitoring at the Estonian Environment Information Center, told the daily newspaper Eesti Paevaleht.

The Delhi government imposed a blanket ban on the use of all plastic bags on Friday in an attempt to tackle the city's mounting rubbish problems, an official said.

Thin plastic bags -- measuring less than 40 microns thick -- were banned in India's capital in 2009, but the new rules will cover all plastic packaging for items such as magazines and greeting cards as well as garbage bags.