• Influence of Earth's tilt on climate studied

    LSU paleoclimatologist Kristine DeLong contributed to an international research breakthrough that sheds new light on how the tilt of the Earth affects the world's heaviest rainbelt. DeLong analyzed data from the past 282,000 years that shows, for the first time, a connection between the Earth's tilt called obliquity that shifts every 41,000 years, and the movement of a low pressure band of clouds that is the Earth's largest source of heat and moisture -- the Intertropical Convergence Zone, or ITCZ.

    "I took the data and put it through a mathematical prism so I could look at the patterns and that's where we see the obliquity cycle, that 41,000-year cycle. From that, we can go in and look at how it compares to other records," said DeLong, who is an associate professor in the LSU Department Geography & Anthropology.

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  • Bird habitat changing quickly as climate change proceeds

    The climatic conditions needed by 285 species of land birds in the United States have moved rapidly between 1950 and 2011 as a result of climate change, according to a recent paper published in Global Change Biology.

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  • Study looks into past climate in Oregon's Coast Range

    Lush greenery rich in Douglas fir and hemlock trees covers the Triangle Lake valley of the Oregon Coast Range. Today, however, geologists across the country are more focused on sediment samples dating back 50,000 years that were dug up by University of Oregon scientists.

    The sediment indicates that the mountainous region, which was not covered in glaciers during the last ice age, was a frost-covered grassy landscape that endured erosion rates at least 2.5 higher than today's, an eight-member team reports in a paper in the journal Science Advances.

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  • How sea spray affects clouds

    All over the planet, every day, oceans send plumes of sea spray into the atmosphere. Beyond the poetry of crashing ocean waves, this salt- and carbon-rich spray also has a dramatic effect on cloud formation and duration.

    In a new paper published this week in the journal Proceedings of the National Academy of Sciences, Colorado State University atmospheric scientist Paul DeMott finds that sea spray is a unique, underappreciated source of what are called ice nucleating particles. These microscopic bits make their way into clouds and initiate the formation of ice, affecting the clouds' composition.

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  • NASA finds much higher methane emissions in Arctic winters

    The amount of methane gas escaping from the ground during the long cold period in the Arctic each year and entering Earth's atmosphere is likely much higher than estimated by current carbon cycle models, concludes a major new study led by San Diego State University and including scientists from NASA's Jet Propulsion Laboratory, Pasadena, California.

    The study included a team comprising ecologists Walter Oechel (SDSU and Open University, Milton Keynes, United Kingdom) and Donatella Zona (SDSU and the University of Sheffield, United Kingdom) and scientists from JPL; Harvard University, Cambridge, Massachusetts; the National Oceanic and Atmospheric Administration, Boulder, Colorado; and the University of Montana, Missoula. The team found that far more methane is escaping from Arctic tundra during the cold months when the soil surface is frozen (generally from September through May), and from upland tundra, than prevailing assumptions and carbon cycle models previously assumed. In fact, they found that at least half of the annual methane emissions occur in the cold months, and that drier, upland tundra can be a larger emitter of methane than wet tundra. The findings challenge critical assumptions in current global climate models. The results are published this week in the Proceedings of the National Academy of Sciences.

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  • Coastal Marshes More Resilient to Sea-Level Rise Than Previously Believed

    Accelerating rates of sea-level rise linked to climate change pose a major threat to coastal marshes and the vital carbon capturing they perform. But a new Duke University study finds marshes may be more resilient than previously believed. 

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  • The impact of Climate change on phytoplankton

    As nations across the globe negotiate how to reduce their contributions to climate change, researchers at Penn are investigating just how the coming changes will impact the planet. What's clear is that the effect extends beyond simple warming. Indeed, the very physics and chemistry of the oceans are also shifting, and are forecast to change even more in the coming decades.

    These changes have implications for, among other things, the single-celled organisms that comprise the base of the ocean's food web and are responsible for half of the world's photosynthetic activity: phytoplankton. Not only are phytoplankton sensitive to changes in climate, they also contribute to those changes, as they can remove carbon from the atmosphere and store it deep in the ocean when they die.

    A micrograph of phytoplankton. Like plants on land, phytoplankton growth is controlled by environmental factors such as light, nutrients, and temperature.

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  • Climate change is impacting lakes faster than oceans

    Climate change is rapidly warming lakes around the world, threatening freshwater supplies and ecosystems, according to a new NASA and National Science Foundation-funded study of more than half of the world's freshwater supply.

    Using more than 25 years of satellite temperature data and ground measurements of 235 lakes on six continents, this study -- the largest of its kind -- found lakes are warming an average of 0.61 degrees Fahrenheit (0.34 degrees Celsius) each decade. The scientists say this is greater than the warming rate of either the ocean or the atmosphere, and it can have profound effects.

    The research, published in Geophysical Research Letters, was announced Wednesday at the American Geophysical Union meeting in San Francisco.

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  • Greenhouse gas emissions from freshwater higher than thought

    Do not underestimate the babbling brook. When it comes to greenhouse gases, these bucolic water bodies have the potential to create a lot of hot air. According to a new analysis in the journal Ecological Monographs, by researchers at the University of Wisconsin–Madison and colleagues, the world’s rivers and streams pump about 10 times more methane into our atmosphere than scientists estimated in previous studies.

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  • A million years ago, Greenland was ice free

    As the Arctic warms, Greenland’s fringe of glaciers is thinning and melting—but the future of the Greenland ice sheet remains a giant question mark. Until recently, that was also true of the ice sheet’s past: Scientists have long debated whether it might have shrunk away to nothing during Earth’s warmest periods. Now, a new study suggests that Greenland was entirely ice free at some point in the last 1.25 million years.

    “We should be worried about the Greenland Ice Sheet,” says Joerg Schaefer, a geochemist from Columbia University’s Lamont-Doherty Earth Observatory in Palisades, New York, and lead author of the findings, presented yesterday at the American Geophysical Union’s annual meeting here.

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