ScienceDaily (Mar. 5, 2010) -- Geologists have found evidence that sea ice extended to the equator 716.5 million years ago, bringing new precision to a "snowball Earth" event long suspected to have taken place around that time.

Led by scientists at Harvard University, the team reports on its work in the journal Science. The new findings -- based on an analysis of ancient tropical rocks that are now found in remote northwestern Canada -- bolster the theory that our planet has, at times in the past, been ice-covered at all latitudes.

"This is the first time that the Sturtian glaciation has been shown to have occurred at tropical latitudes, providing direct evidence that this particular glaciation was a 'snowball Earth' event," says lead author Francis A. Macdonald, an assistant professor in the Department of Earth and Planetary Sciences at Harvard. "Our data also suggests that the Sturtian glaciation lasted a minimum of 5 million years."

The survival of eukaryotic life throughout this period indicates sunlight and surface water remained available somewhere on the surface of Earth. The earliest animals arose at roughly the same time, following a major proliferation of eukaryotes.

Even in a snowball Earth, Macdonald says, there would be temperature gradients on Earth and it is likely that ice would be dynamic: flowing, thinning, and forming local patches of open water, providing refuge for life.

ScienceDaily (Mar. 5, 2010) -- A section of the Arctic Ocean seafloor that holds vast stores of frozen methane is showing signs of instability and widespread venting of the powerful greenhouse gas, according to the findings of an international research team led by University of Alaska Fairbanks scientists Natalia Shakhova and Igor Semiletov.

The research results, published in the March 5 edition of the journal Science, show that the permafrost under the East Siberian Arctic Shelf, long thought to be an impermeable barrier sealing in methane, is perforated and is leaking large amounts of methane into the atmosphere. Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.

"The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world's oceans," said Shakhova, a researcher at UAF's International Arctic Research Center. "Subsea permafrost is losing its ability to be an impermeable cap."

CHATTANOOGA, Tenn. (AP) -- More than a year after a Tennessee coal ash spill created one of the worst environmental disasters of its kind in United States history, the problem is seeping into several other states.

It began on Dec. 22, 2008, when a retaining pond burst at a coal-burning Tennessee Valley Authority power plant, spilling 5.4 million cubic yards of coal ash across 300 acres into the Emory River and an affluent shoreline community near Knoxville. It was enough ash to cover a square mile five feet deep.

While the T.V.A.'s cleanup has removed much of the ash from the river, the arsenic- and mercury-laced muck or its watery discharge has been moving by rail and truck through three states to at least six sites. Some of it may end up as far away as Louisiana.

At stops along the route, new environmental concerns are popping up. The muck is laden with heavy metals linked to cancer, and the federal Environmental Protection Agency is considering declaring coal ash hazardous.

"I'm really concerned about my health," said James Gibbs, 53, a retiree who lives near a west-central Alabama landfill that is taking the ash. "I want to plant a garden. I'm concerned about it getting in the soil."

WASHINGTON -- Lower levels of oxygen in the Earth's oceans, particularly off the United States' Pacific Northwest coast, could be another sign of fundamental changes linked to global climate change, scientists say.

They warn that the oceans' complex undersea ecosystems and fragile food chains could be disrupted.

In some spots off Washington state and Oregon, the almost complete absence of oxygen has left piles of Dungeness crab carcasses littering the ocean floor, killed off 25-year-old sea stars, crippled colonies of sea anemones and produced mats of potentially noxious bacteria that thrive in such conditions.

Areas of hypoxia, or low oxygen, have long existed in the deep ocean. These areas -- in the Pacific, Atlantic and Indian oceans -- appear to be spreading, however, covering more square miles, creeping toward the surface and in some places, such as the Pacific Northwest, encroaching on the continental shelf within sight of the coastline.

"The depletion of oxygen levels in all three oceans is striking," said Gregory Johnson, an oceanographer with the National Oceanic and Atmospheric Administration in Seattle.

In some spots, such as off the Southern California coast, oxygen levels have dropped roughly 20 percent over the past 25 years. Elsewhere, scientists say, oxygen levels might have declined by one-third over 50 years.

BG Says U.K. Forecast for Natural-Gas Demand Too Low

March 3 (Bloomberg) -- BG Group Plc said U.K. natural-gas demand will be 30 percent higher than government forecasts by 2020 as wind-energy projects are delayed and aging electricity plants close, requiring more gas-fired power generation.

"The projections from the U.K. government are based on an optimistic potential of renewables to deliver by 2020 and the installation of thousands of offshore wind turbines in particular," Roger Tucker, BG's senior vice president for Europe, said today at the Flame conference in Amsterdam.

Britain will consume 95 billion cubic meters of gas a year by 2020, about a third more than the government's forecast, he said.

The U.K. Department of Energy and Climate Change has said annual demand will be "managed down" to 73 billion cubic meters in 10 years time as offshore wind farms are built.

Britain, facing dwindling North Sea gas output and aging nuclear resources, has begun a $120 billion offshore wind program to help avert an energy shortfall and meet emission targets. RWE AG, Statoil ASA and Centrica Plc were among winners of wind-farm permits in the country's January licensing round, which is designed to add 32,200 megawatts of capacity.

"This is an engineering challenge equivalent to building eight channel tunnels in 10 years," Tucker said, referring to the 30-mile rail tunnel underneath the English Channel and citing Carbon Trust data.