Tuesday, August 24, 2010

Geoengineering won't curb sea-level rise

Unless they involve extreme measures, geoengineering approaches to offset the effects of human-driven climate changes won't do much to combat rising sea levels, an international team of scientists reports in the Proceedings of the National Academy of Sciences1.

That is because sea levels respond slowly to changes in Earth's temperature, says John Moore, a palaeoclimatologist at Beijing Normal University and lead author of the study.

"We've got this 150-year legacy of fossil-fuel [burning], land-use changes, et cetera," he says. "You can't just slam on the brakes instantaneously."

Moore and his team examined two proposed geoengineering schemes: mirrors orbiting in space to reduce incoming sunlight, and sulphates being shot into the upper atmosphere to create a bright, sunlight-reflecting haze — similar to the one produced naturally by the 1991 eruption of Mount Pinatubo in the Philippines. Either scheme could reduce incoming solar energy by about 1–4 watts per square metre, enough to offset the atmospheric warming caused by carbon dioxide build-up until at least 2070.

more from Nature

Sunday, August 08, 2010

Green living: Off the grid families pioneer sustainable energy lifestyles

Living "off the grid" can conjure fantasies of Swiss Family Robinson-style ingenuity in paradise. Or, for those with less love of roughing it, it can simply remind them of the hardscrabble self-reliance throughout much of the developing world, where millions cook over fires, bathe in streams, and consider the glow of a bare light bulb a luxury.

In the United States, off-the-grid living – without relying on government entities or utility companies to provide electricity, heat, gas, and water – often is associated with gritting it out on the survivalist fringe.

But an increasing range of Americans are leading a snug, even smug, lifestyle totally or mostly unhitched from public utilities. Using nature – the sun, wind, water, and the earth itself – they cheaply warm and cool their homes and power everything from a blender to a giant flat-screen TV to a raging hot tub. And with the constant concern about global warming and messy dependence on fossil fuels, it's natural that growing numbers of Americans – "the foot soldiers" of energy independence, as one expert calls them – would begin taking steps to untether themselves from the grid.

For Wayah Hall, going off the grid in a cabin 26 miles from downtown Asheville, N.C., was a way to live in harmony with nature and avoid reliance on electricity that comes from the region's coal-burning power plant that pumps smog into the famous Blue Ridge Mountains haze.

Mr. Hall, an outdoor-skills instructor, and his wife, Alicia Bliss Hall, a natural healer, live in a kind of off-the-grid neighborhood with another young couple: Jason Brake, a professional muralist, and his wife, Diana Styffeler, a mountain bike excursion leader. Their two cabins, nestled in temperate rain forest, are powered with electricity that comes exclusively from solar panels mounted on a wagon that they wheel around the property to catch the best rays. Their water comes from a swiftly flowing stream; wood-burning stoves heat the cabins and even an outdoor hot tub; and indoor, waterless composting toilets built decoratively out of tree stumps mean they don't need a sewer system. They're installing a hydropower system in the stream that will add to the solar power.

more from the CS Monitor

Saturday, August 07, 2010

Coverage Turns, Cautiously, to Spill Impact

And on the 106th day — after all the top kills and top hats and junk shots — the runaway oil well in the Gulf of Mexico finally seemed close to being tamed. Or was it?

News organizations are grappling with the same questions that the rest of the country is, after spending months watching oil gush into the water: Is the spill really over? And how damaging will it ultimately be to the gulf’s environment and economy?

It could be “the beginning of the end,” Katie Couric told viewers Tuesday on the “CBS Evening News.” The same phrase, with an extra “perhaps” attached to it, was used over on “NBC Nightly News.” But Diane Sawyer did away with the caveats on ABC.

“Final fix,” she declared Tuesday on “World News Tonight.” “Tonight the permanent seal of the oil spill is under way.”

Newsrooms are grappling with the same questions that the rest of the country is, after spending months watching oil gush into the water: Is the oil spill really over? And how damaging will it ultimately be to the gulf’s environment and economy?

The conundrum for television, print and online journalists alike has been that no one wanted to declare “Mission Accomplished” on the gushing oil portion of the calamity prematurely. But no one wanted to be the last to report that the leak had been plugged.

Assuming the current cement plug holds, any number of dates could qualify as the end of the spill. No significant oil has leaked since the well was tightly capped in mid-July, officials said — an event “NBC Nightly News” also said “could be the beginning of the end.”

This week’s “static kill,” an effort to plug the well with mud and then cement, seems to have worked. But the final stake through the heart — the relief well being drilled to make sure the well is dead — is not expected until later this month.

Then there is the once-bitten, twice-shy phenomenon, some news executives said, citing all the false starts and overly optimistic predictions of the past three months — the initial claim that there did not appear to be a significant oil leak, the vastly underestimated early guesses of how much oil was pouring into the gulf, the overly rosy assessments of past efforts to stanch the flow.

more from the NY Times

Thursday, August 05, 2010

A Looming Oxygen Crisis and Its Impact on World’s Oceans

The Deepwater Horizon oil spill is overshadowing another catastrophe that’s also unfolding in the Gulf of Mexico this summer: The oxygen dissolved in the Gulf waters is disappearing. In some places, the oxygen is getting so scarce that fish and other animals cannot survive. They can either leave the oxygen-free waters or die. The Louisiana Universities Marine Consortium reported this week that this year’s so-called “dead zone” covers 7,722 square miles.

Unlike the Deepwater Horizon disaster, this summer’s dead zone is not a new phenomenon in the Gulf. It first appeared in the 1970s, and each summer it has returned, growing bigger as the years have passed. Its expansion reflects the rising level of fertilizers that farmers in the U.S. Midwest have spread across their fields. Rain carries much of that fertilizer into the Mississippi River, which then delivers it to the sea. Once the fertilizer reaches the Gulf, it spurs algae to grow, providing a feast for bacteria, which grow so fast they use up all the oxygen in their neighborhood. The same phenomenon is repeating itself along many coastlines around the world. This summer, a 377,000-square-kilometer (145,000-square-mile) dead zone appeared in the Baltic Sea. In 2008, scientists reported that new dead zones have been popping up at an alarming rate for the past 50 years. There are now more than 400 coastal dead zones around the world.

As serious as these dead zones are, however, they may be just a foreshadowing of a much more severe crisis to come. Agricultural runoff can only strip oxygen from the ocean around the mouths of fertilizer-rich rivers. But global warming has the potential to reduce the ocean’s oxygen content across the entire planet. Combined with acidification — another global impact of our carbon emissions — the loss of oxygen could have a major impact on marine life.

more from Yale 360

Sunday, August 01, 2010

Oil Spill Dispersants Shifting Ecosystem Impacts in Gulf, Scientists Warn

A seemingly feel-good story showed up this week on the nation's front pages and newscasts: The oil that befouled the Gulf of Mexico for 86 days is vanishing from the surface, leaving workers with little to clean.

But scientists warn the oil's ecological impacts are shifting, not ebbing, thanks to massive volumes of dispersants that have kept the crude beneath the waves.

"This is a management decision, to use dispersants," College of William and Mary marine science professor Robert Diaz said yesterday. "It doesn't make the oil go away, it just puts it from one part of the ecosystem to another."

That dispersed oil now hovers, diluted in the water column, posing a challenge for scientists to track and measure the subsea plumes. Mapping the long-term effects of the nearly 2 million gallons of dispersant used by BP PLC may well be equally difficult, given the array of unanswered questions that surround the products' rapid breakdown of oil droplets and their chronic toxicity.

In other words, while dispersants may have helped spare the Gulf's birds, the chemicals are likely shifting dangers to other species lower in the food chain. The National Research Council described dispersant use in 2005 as "a conscious decision" to direct hydrocarbons to one part of the marine ecosystem, "decreasing the risk to water surface and shoreline habitats while increasing the potential risk to organisms in the water column and on the seafloor."

Diaz spoke at a Capitol Hill briefing aimed at guiding future research into dispersants, which remain a politically volatile topic even as their use in the Gulf tapers off thanks to the capped Macondo wellhead. A May meeting at the University of New Hampshire's Coastal Response Research Center, planned by government scientists and oil industry representatives, yielded a consensus judgment that dispersant use "has generally been less environmentally harmful than allowing the oil to migrate on the surface into the sensitive wetlands."

Another group of scientists, however, issued a public plea (pdf) last week that decried dispersants and warned that, mixed with oil, the products "pose grave health risks to marine life and human health."

more from the NY Times