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Natural gas in some drinking water due to leaky gas wells, not fracking

A shale gas well being drilled in Louisiana.

The primary public concern surrounding fracking—the fracturing of shale rock layers with hydraulic pressure to release the natural gas and oil they contain—has been the perceived risk to drinking water. After all, the water used to fracture the rock is laced with chemicals that enhance the process, and some of them are hazardous. While those chemicals haven’t really shown up in water wells, natural gas has. If natural gas isn’t identified and vented, it could collect in buildings and pose an explosion hazard—videos of garden hoses turned into flame-throwers have made the rounds.

But tying that natural gas to fracking projects isn’t as straight-forward as many assume since there are natural sources of methane as well. One group of researchers has been studying this question for several years, focusing on Pennsylvania, where the Marcellus Shale has been targeted by the natural gas industry. A controversial analysis the group performed concluded that natural gas in well water was more common near active natural gas production wells, indicating that much of the contamination was related to recent human activities rather than natural conditions.

The researchers also looked for hints of natural migration of fluids from the Marcellus Shale, which is deep underground, to the well water, which is taking from sources closer to the surface. By analyzing elements like chlorine and strontium, they identified the fingerprint of briney Marcellus fluid in some of the water wells, which pull from an aquifer where concentrations of those elements are much lower. They concluded that some of those fluids were present, casting doubt on the idea that the Marcellus Shale was too tight a seal to allow fluid to escape upward into drinking water. That work also indicated that some of the methane-contaminated wells seemed to be impacted by naturally occurring methane, but typically the ones close to natural gas production wells weren't.

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2002 Larsen B ice shelf collapse likely due to rising temps

Satellite view of the remains of the Larsen B ice shelf on March 7, 2002.

A number of noteworthy studies have recently highlighted the importance of what's going on at the bottom of glaciers that flow into the ocean. The topography beneath the glacier—as well as the “grounding line” beyond which a glacier becomes thin enough to float in the water rather than rest on the seafloor—have a lot to do with its stability.

In 2002, the Larsen B ice shelf on the Antarctic Peninsula abruptly collapsed, scattering 3,200 square kilometers (yes, approximately one standard Rhode Island unit of area) of 200 meter thick ice into the waves. But why? Did warming water beneath the ice shelf loosen it from the grounding line and destabilize the ice shelf in front? Or can we pin the blame on the warming temperatures of the region?

With the ice shelf gone, researchers looking for answers have been able to look at the seafloor that once sat beneath it. In 2006, a research vessel spent some time at the site of the collapse, looking for clues. The findings of that team, led by the Italian National Institute of Oceanography and Experimental Geophysics’ Michele Rebesco and the University of South Florida’s Eugene Domack, have now been published in the journal Science.

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A big chunk of the Sierra Nevada caught fracturing on video

If you like geology, you’re used to relying on an active imagination. Most geologic processes occur too slowly to see them play out for yourself. Many of the exceptions are dangerous enough that you might not want a front row seat or rare enough that the odds of being there to witness it are disheartening. Sometimes, though, the Earth throws us a bone—or in this case, a gigantic slab of granite.

One interesting way that rocks weather and crumble apart is called “exfoliation.” Like the skin-scrubbing technique, this involves the outermost layers of exposed igneous or metamorphic bedrock sloughing off in a sheet. Over time, this tends to smooth and round the outcrop—Yosemite’s Half Dome providing a spectacular example.

We’re not entirely sure just what drives the peeling of an outcrop’s skin like this, but the classic explanation is that it’s the result of bringing rocks that formed at great pressure up to the surface. Once there, the outer layers can expand slightly, creating a physical mismatch with the layers below them.

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New ice core records show Greenland in sync with the rest of the globe

Researchers working at the site of a recent ice core (designated NEEM) in northern Greenland.

Any interesting field of science (read: all of them) has its little mysteries—things that don’t quite make sense. They're the currency of a research scientist, since they provide interesting questions. One of these little stumpers is found in Greenland ice cores.

Ice cores, with their annual layering, have provided a revolutionary window into Earth’s climate history. By analyzing two isotopes of oxygen in the water molecules, researchers found a record of changing climate. In warmer times, the heavier 18O atoms become a little more common. In colder times, they are less so. This revealed all kinds of information about the last few glacial cycles, which are controlled by subtle changes in Earth’s orbit and amplified by positive feedbacks like CO2.

There are, however, complications. The oxygen isotope ratio can also shift for reasons other than temperature, like changing snowfall patterns. The complications gave researchers reason to be skeptical of a strange detail at the end of the last ice age.

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Ocean acidification XPRIZE competition begins

An earlier version of Team Durafet's sensor.

A year ago, we reported on the launch of a new XPRIZE competition—not to launch a rocket, but to build a better device to measure ocean pH. The aim was to produce something that could be added to automated platforms like ARGO floats to greatly expand pH data collection, which presently has to rely mostly on expensive research vessel cruises.

Teams are competing for a pair of $1 million prizes put up by Wendy Schmidt—who, together with her husband Eric Schmidt, just donated $500,000 to help keep the famous atmospheric CO2 monitoring program at the Scripps Institution of Oceanography running.

The first of three stages in the competition will begin next week. The 18 teams who were selected for the competition will place their devices into carefully controlled tanks of water at the Monterey Bay Aquarium. Over three months, the devices will be judged on the accuracy, precision, and stability of their pH measurements.

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25 year experiment shows ants can break down minerals, sequester CO2

If you want a role model for work ethic in the animal kingdom, you’d do well to pick the ant. Maintaining tunnels, gathering food, and defending the colony are all in a solid day’s work. Now you might be able to cross off another item on the ant to-do list: pulling carbon dioxide out of the atmosphere.

Over geologic timescales, the Earth has a convenient regulator on its thermostat: the weathering of many minerals. During their breakdown, they react with carbon dioxide, which converts them into a clay mineral while also producing carbonate. In a warmer climate, weathering ramps up, removing more CO2 from the atmosphere. This provides a cooling influence. In a cooler climate, weathering slows and CO2 can accumulate in the atmosphere, nudging temperatures upwards.

Some of this is simply the result of physical weathering of exposed rock at the surface, but living organisms contribute as well. Tree roots penetrate cracks and pry rocks apart. Lichens and fungi in soil slowly dissolve rock. Burrowing things move material around.

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Death Valley’s famous moving stones, caught in the act

Mario is just a video game, and rocks don’t have legs. Both of these things are true. Yet, like the Mario ghosts that advance only when your back is turned, there are rocks that we know have been moving—even though no one has ever seen them do it.

The rocks in question occupy a spot called Racetrack Playa in Death Valley. Playas are desert mudflats that sometimes host shallow lakes when enough water is around. Racetrack Playa gets its name from long furrows extending from large rocks sitting on the playa bed—tracks that make it look as if the rocks had been dragged through the mud. The tracks of the various rocks run parallel to each other, sometimes suggesting that the rocks had made sharp turns in unison, like dehydrated synchronize swimmers.

Many potential explanations have been offered up (some going back to the 1940s) for this bizarre situation, as the rocks seem to only move occasionally and had never been caught in the act. One thing everyone could agree on was that it must occur when the playa is wet and the muddy bottom is slick. At first, suggestions revolved around especially strong winds. One geologist went as far as to bring out a propeller airplane to see how much wind it would take.

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American Southwest has 80% chance of decade-long drought this century

Satellite view of Southern California and Nevada as of June.

In a good year, the management of water resources in the American West is contentious. When a drought hits, most everyone feels it, and this year is certainly no exception. The notion of sustainability in water-strapped places isn’t much more complicated than balancing a checking account. And the budget projections aren’t exactly encouraging.

The last thing this situation needs is a decrease on the supply side. Unfortunately, precipitation in the Southwestern US is projected to decline as a result of anthropogenic climate change. Double unfortunately, the last century isn’t even a very good baseline for the region’s climate without climate change. Records from things like tree rings show drier periods in the past. A recent study led by Cornell’s Toby Ault attempts to pull this all together to improve our understanding of future drought risk in the region.

The worst US droughts of the 20th century were the 1930s “Dust Bowl” in the central US and the 1950s in the Southwest. In the past, the Southwest has averaged one or two of these almost-decade-long droughts per century, but there have also been droughts longer than anything in the historical record—droughts lasting several decades.

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Cleaner air helps pay for reducing carbon emissions

It has been a long time since we could reasonably ask whether something should be done about climate change. The much more interesting (and challenging) discussion revolves around the nitty-gritty of how best to do something about the problem. There are many conceivable possibilities, but some will be more expensive, and some will be less effective—there are plenty of variables to consider when plotting the best and wisest path forward.

The most obvious questions to ask about any policy proposal are how much it will cost to implement and how much harm it will help us avoid. But it’s also worthwhile to consider whether the policy might have any positive (or negative) side effects separate from the climate impacts.

We know, for example, that greenhouse gases aren’t the only by-products of burning fossil fuels—there are other types of pollutants as well. Those pollutants have environmental and human health impacts that would be reduced right along with the greenhouse gas emissions if fossil fuel use were to decline.

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Models challenge temperature reconstruction of last 12,000 years

Ilulissat, Greenland in the summer.

Climate records, like tree rings or ice cores, are invaluable archives of past climate, but they each reflect their local conditions. If you really want a global average for some time period, you’re going to have to combine many reliable records from around the world and do your math very carefully.

That’s what a group of researchers aimed to do when (as Ars covered) they used 73 records to calculate a global overview of the last 11,000 years—the warm period after the last ice age that's called the Holocene. The Holocene temperature reconstruction showed a peak about 7,000 years ago, after which the planet slowly cooled off by a little over 0.5 degrees Celsius until that trend abruptly reversed over the last 150 years. That behavior mirrored the change in Northern Hemisphere summer sunlight driven by cycles in Earth’s orbit.

A new study published in the Proceedings of the National Academy of Sciences and led by the University of Wisconsin’s Zhengyu Liu delves into a problem with that pattern—and it’s not what climate models say should have happened.

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