As predicted, humongous iceberg breaks away from Greenland glacier

A massive iceberg larger than Manhattan has broken away from the floating end of a Greenland glacier this week, an event scientists predicted last autumn.

The giant ice island is 46 square miles (120 square kilometers), and separated from the terminus of the Petermann Glacier, one of Greenland's largest.

The Petermann Glacier last birthed — or "calved" — a massive iceberg two years ago, in August 2010. The iceberg that broke off and floated away was nearly four times the size of Manhattan, and one of the largest ever recorded in Greenland.

Although the new iceberg isn't as colossal as its 2010 predecessor, its birth has moved the front end of the massive glacier farther inland than it has been in 150 years, Andreas Muenchow, an associate professor of physical ocean science and engineering at the University of Delaware, said in a statement.

Jason Box, a scientist with Ohio State University's Byrd Polar Research Center, has also been monitoring the Petermann Glacier, and in September 2011, he told OurAmazingPlanet that a growing crack likely would sever the glacier once warmer weather took hold during the summer months.

"We can see the crack widening in the past year through satellite pictures, so it seems imminent," Box said at the time.

Muenchow said that the newest ice island broke away on Monday morning (July 16).

Although iceberg birth is a natural, cyclical process, when the process speeds up, there are consequences.

The floating ends of glaciers, known as ice shelves, act as doorstops. When these ice shelves suddenly splinter and weaken or even collapse entirely, as has been observed in Antarctica, the glaciers that feed them speed up, dumping more ice into the ocean and raising global sea levels.

"The Greenland ice sheet as a whole is shrinking, melting and reducing in size as the result of globally changing air and ocean temperatures and associated changes in circulation patterns in both the ocean and atmosphere," Muenchow said.

Source: Christian Science Monitor

2010 Could Be Hottest Year Yet

Duh! Thanks for that news flash!

Federal climate scientists say that 2010 is shaping up to be the hottest year yet seen, with average global temperatures for the first six months of the year beating the previous record, set in 1998, by 1.19 degrees Fahrenheit. The National Climatic Data Center's scientists added that this year's warm weather did not appear to be a one-off. "Each of the 10 warmest average global temperatures recorded since 1880 have occurred in the last fifteen years," the center reported. The center also notes that Arctic sea-ice shrank to record lows in June, covering an area almost 11 percent lower than the usual June average, marking the 19th consecutive year of summer ice declines. At the other end of the Earth, Antarctic sea ice was up a little more than 8 percent, in the largest June expansion on record.

Credits: Slate Magazine via MSNBC

Could Cleaner Air Actually Intensify Global Warming?

As much of the world marked Earth Day this past week, the Environmental Protection Agency reported that air pollution has declined dramatically over the last 20 years. It sounds like good news, but science writer Eli Kintisch argues that there's a surprising downside: Cleaner air might actually intensify global warming.

"If we continue to cut back on smoke pouring forth from industrial smokestacks, the increase in global warming could be profound," Kintisch writes in an opinion piece for the Los Angeles Times.

Kintisch isn't talking about greenhouse gases like carbon dioxide; he's talking about another kind of pollutant we put in the sky -- "like aerosols from a spray can," he tells NPR's Guy Raz. "It turns out that those particles have a profound effect on maintaining the planet's temperature."

Greenhouse gases and aerosol pollutants work in opposing ways on the Earth's climate, Kintisch explains. "The greenhouse gases warm the planet when they're emitted, because they absorb heat reflected up from the ground -– the greenhouse effect. These aerosols, though, do the opposite. They block sunlight, they make clouds more reflective -- and by doing that, they actually cool the planet.

"The problem is that we're cutting the cooling pollution as we make our air cleaner," he says.

The Scope Of The Problem: Still A Mystery

Some scientists, he says, are confident that this is connected to global warming, but they don't know how large the effect is. "That's the frightening thing, because if it's a big cooling effect, it means that we've been actually warming the planet more than we know," Kintisch says. "As we take away that unexpectedly helpful cooling mask, we're going to be facing more global warming than we expected.

"If, however, the aerosol cooling is less than we fear, then it won't be such a big deal as we clean our air, though it will still be an effect."

The solution, of course, isn't to stop cutting air pollution. "We have to continue doing that, because these pollutants contribute to asthma, they contribute to respiratory diseases, they cause all sorts of health problems and they make our environment dirty," he says. "But there's a variety of answers that are more sophisticated than simply continuing to pollute."

Gunk To The Rescue

One of those answers is pretty radical: injecting new pollutants into the stratosphere while we continue to clean up our emissions. It's one of the theories of "geoengineering" that Kintisch explores in his new book, Hack the Planet.

It sounds contradictory, but the idea is actually based on a natural polluter -- volcanoes. Kintisch points out that nearly 20 years before the eruption of Eyjafjallajokull in Iceland shut down air traffic across Europe, a much bigger volcano in the Philippines affected the climate over a much broader area.

"In 1991, when Mount Pinatubo erupted, it put tons of sulfur into the stratosphere," he says. "Those sulfur aerosols cooled the planet by as much as a degree Celsius in a decade."

So if we found ourselves in a climate crisis where oceans were rising rapidly and coastal areas were flooding, some scientists think "we could mimic the cooling effect of natural volcanoes and make man-made volcanoes by putting our own gunk, essentially, up in the upper atmosphere," Kintisch says.

"It's unclear whether we would be able to respond and actually stop a disintegrating ice sheet situation," he cautions. "However, some scientists think we're getting near that worse-case scenario right now."

Credits: NPR