• LLNL scientist Benjamin Santer and his climbing group ascend Mt. St. Helens via the "Dogshead Route" in April 1980, about a month before its major eruption. The group was the last to reach the summit of Mt. St. Helens before its major eruption that May. New research by Santer and his colleagues shows that volcanic eruptions contribute to a recent warming "hiatus."

    The past two years have been marked by extreme weather in the Northern Hemisphere. It’s been either too warm and too cold. “Snowmaggedon” in the Northeast turned into this summer’s record-breaking sweat fest. The two extremes don’t cancel each other out, however. On the whole, the warm weather has beaten out the cold in frequency and magnitude, say Scripps Institute of Oceanography scientists. Moreover, they say that the cold weather can be explained by a natural climate cycle having to do with changes in atmospheric pressure at sea level, called the North Atlantic Oscillation. The heat waves could only be explained by a trend towards warmer and warmer weather that is believed to be climate change. “Over the last couple of years, natural variability seemed to produce the cold extremes, while the warm extremes kept trending just as one would

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  • A massive crack runs about 29 kilometers (18 miles) across the Pine Island Glacier's floating tongue, marking the moment of creation for a new iceberg that will span about 880 square kilometers (340 square miles) once it breaks loose from the glacier. Lawrence Livermore research shows that the glacier's recent melt may go on for decades or centuries.

    The IPCC assumes sea levels have barely changed over the past two millennia, setting today’s rate of 2 to 3 millimeters per year in stark contrast. But some scientists are questioning that simplification. Ocean levels, it seems, have never been stagnant. Glaciers and ice sheets have come and gone. Land masses have moved course. The Earth’s crust has rebounded following glacial melt from the last Ice Age, and that’s changed the volume of water in the oceans too. Understanding the variability is key to predicting future sea level rise, write W. Roland Gehrels from the University of Plymouth, UK and colleagues in a paper published in the most recent issue of Eos, a publication of the American Geophysical Union. They say that falling sea levels have been the overall natural trend over the last 1,000 years, according to proxy data, making today’s

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  • EarlyClimate

    Climate change destabilizes natural ecosystems, but does it also instigate war? A new study in the journal Nature sheds light on the hotly contested debate about whether climate variability plays a role in the onset of violence, especially in poor countries. The researchers led by Solomon Hsiang from Columbia University’s School of International and Public Affairs focused on natural global climate cycles. They found that the arrival of El Niño, which raises temperatures and cuts rainfall in tropical countries, is associated with a doubling of the risk of civil war in 90 tropical countries. As such, El Niño may help account for about one-fifth of worldwide conflicts during the past 50 years. Historians and climatologists have long associated heat and droughts with the shaking and falling of past civilizations. Just think of Jared Diamond‘s bestseller: Collapse: How Societies Choose to

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  • Saturn jet stream

    It’s not every day that you discover a new ocean current – especially one in the Arctic that could be impacted by climate change. But scientists at the University of Bergen in Norway, in concert with the Woods Hole Oceanographic Institute, have done just that. Deep below the ocean surface off Iceland, Kjetil VÃ¥ge and colleagues came across what they’ve named the North Icelandic Jet, a key contributor to the Atlantic Ocean conveyor belt. This overturning of warm water from the tropics with dense, cool water from Arctic helps regulate climate along the Atlantic seaboard. It’s why Europe isn’t freezing cold, despite being at such high latitudes. In a paper published online this week in the journal Nature Geoscience, the authors state that this newly discovered jet stream is accountable for about half the total overflow transport to the Arctic’s

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  • IceBite Lake Joyce Antarctica

    Scientists trying to map the melting of ice in Antarctica have come up with a discovery. Much of the ice flowing into the ocean is not the result of “deformation” of glaciers. Rather, the ice is sliding along bedrock. “That’s critical knowledge for predicting future sea level rise,” said Thomas Wagner, a NASA cryospheric program scientist in a press release. “It means that if we lose ice at the coasts from the warming ocean, we open the tap to massive amounts of ice in the interior.” The study, published last week in the online journal Science, involved the first complete map of Antarctic ice sheet flow. Although parts of Antarctica have been well document aerially, the vast extent of East Antarctica, which comprises more than three-quarters of the continent, has been devoid of quality data. Using 900 satellite tracks and

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  • Cloud plumes from cracks of open water in the Arctic sea ice cover. Image credit: University of Hamburg, Germany

    Arctic sea ice is melting at a fast and steady rate. Or is it?  Scientists at the National Center for Atmospheric Research (NCAR) have discovered that the polar ice might temporarily expand for as a long as a decade before succumbing to longer term melting trends. In a study published this week in the journal Geophysical Research Letters, the scientists explain this surprising conclusion. Using computer simulations, they found that the amount of sea ice loss over the 20th century could not be attributed to climate change alone. About half of it was the result of natural forces acting on the climate. The findings demonstrate that climate change offers an only partial picture to the iciness of Arctic seas. Wind patterns, for example, could have a cooling affect. And sometimes these natural forces outstrip the warming effects of climate change

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  • Carbon cenospheres are tiny, carbon-rich particles that form when coal and heavy fuel are heated intensely. Scientists have now learned that cenospheres can form in the wake of asteroid impacts, too.
Credit: Mark Harvey / Indiana University

    Hydroelectricity is often posed as a carbon-free energy source. But get this. Some hydroelectric dams Рparticularly in the tropics Рare even worse than fossil fuel power plants. A study published in the Journal of Geophysical Research examined greenhouse gas emissions coming from a large hydroelectic plant in Brazil: the Balbina Dam along the Uatuṃ River in the central Amazon basin. This dam flooded out more than 900 square miles of lush, tropical rainforest when it was built in 1987 Рthe first knock to its green credentials. On the whole, dams throughout the world contribute about 4 percent of anthropogenic sources of CO2. But according to the study, led by the National Institute of Amazonian Research in Brazil, very few tropical reservoirs were included in that assessment, making dams a potentially worse source of power than has been

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  • Near spacecraft, white crater on asteroid Eros. The lighter material is either fresh or from some unknown weathering process.

    Experts in the field of “climate communications” (yes, there is one), say this summer’s record-breaking temperatures across the country will have little long term impact once snowy weather sinks in this winter. Yes, people are that ADD when it comes to having a weather memory. Part of the confusion is that as weather changes, all the vagaries can chart people off course and keep them from seeing the bigger picture of climate. Now, if sweltering summers become the norm, or the expectation, it’s possible that people will begin to face how the climate is dramatically changing. And that’s just the kind of perspective that’s most accurate when it comes to understanding climate change. Climatologist Heidi Cullen has written a new book – The Weather of the Future: Heat Waves, Extreme Storms, and other Scenes from a Climate Changed Planet. In

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  • Cloud plumes from cracks of open water in the Arctic sea ice cover. Image credit: University of Hamburg, Germany

    In the late summer of 2007, lightening struck a remote corner of the Arctic on Alaska’s North Slope and burned for three months. The tundra soil there was dry because the permafrost, which normally encapsulates the carbon-rich soil in an icy sealant, had melted. The fire burned until October snowfalls put it out, but left a char the size of Cape Cod – some 400 square miles- and large enough to see from space. Michelle Mack, a biologist from the University of Florida, and Syndonia Bret-Harte, of the University of Alaska-Fairbanks, wondered how much carbon had been released during that long, hot burn. In a paper published this week in the journal Nature, they concluded that the carbon loss from this one fire was “unprecedented.” The amount of carbon that had been released into the atmosphere was the equivalent of

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  • Warming Arctic unleashing toxic chemicals

    A decade after nations banded together to ban some of the most persistent toxic chemicals, they are now leaching back out into the environment as the planet warms. In a study published in the July 24 online edition of the journal Nature Climate Change, researchers led by the Air Quality Research Division of Environment Canada examined concentrations of so-called “persistent organic pollutants” (POPs) at two Arctic monitoring stations in Svalbard, Norway and Canada. These long-lasting pollutants, known as the”dirty dozen,” include DDT, which was used for decades for pest control in farming and for public health, and PCBs, used in coolants and as plasticizers in paints and cements. Both were banned in the 2001 international Stockholm Convention because of adverse health and environmental impacts. Since the early 1990s levels of POPs have been decreasing as nations phased out their uses.

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