A simple rule can accurately predict when Earth’s climate warms out of an ice age, according to new research led by UCL.
In a new study published in Nature, researchers from UCL, University of Cambridge and University of Louvain have combined existing ideas to solve the problem of which solar energy peaks in the last 2.6 million years led to the melting of the ice sheets and the start of a warm period. (more…)
AUSTIN, Texas — Thwaites Glacier, the large, rapidly changing outlet of the West Antarctic Ice Sheet, is not only being eroded by the ocean, it’s being melted from below by geothermal heat, researchers at the Institute for Geophysics at The University of Texas at Austin (UTIG) report in the current edition of the Proceedings of the National Academy of Sciences.
The findings significantly change the understanding of conditions beneath the West Antarctic Ice Sheet where accurate information has previously been unobtainable. (more…)
Pine Island Glacier is one of the biggest routes for ice to flow from Antarctica into the sea. The floating ice shelf at the glacier’s tip has been melting and thinning for the past four decades, causing the glacier to speed up and discharge more ice.
Understanding this ice shelf is a key for predicting sea-level rise in a warming world. A paper published Jan. 2 in the advance online version of the journal Science shows that the ice shelf melting depends on the local wind direction, which is tied to tropical changes associated with El Niño. (more…)
AUSTIN, Texas — In a development that will help predict potential sea level rise from the Antarctic ice sheet, scientists from The University of Texas at Austin’s Institute for Geophysics have used an innovation in radar analysis to accurately image the vast subglacial water system under West Antarctica’s Thwaites Glacier. They have detected a swamp-like canal system beneath the ice that is several times as large as Florida’s Everglades.
The findings, as described last week in the Proceedings of the National Academy of Sciences, use new observational techniques to address long-standing questions about subglacial water under Thwaites, a Florida-sized outlet glacier in the Amundsen Sea Embayment considered a key factor in projections of global sea level rise. On its own, Thwaites contains enough fresh water to raise oceans by about a meter, and it is a critical gateway to the majority of West Antarctica’s potential sea level contribution of about 5 meters. (more…)
PASADENA, Calif. — Ocean waters melting the undersides of Antarctic ice shelves are responsible for most of the continent’s ice shelf mass loss, a new study by NASA and university researchers has found.
Scientists have studied the rates of basal melt, or the melting of the ice shelves from underneath, of individual ice shelves, the floating extensions of glaciers that empty into the sea. But this is the first comprehensive survey of all Antarctic ice shelves. The study found basal melt accounted for 55 percent of all Antarctic ice shelf mass loss from 2003 to 2008, an amount much higher than previously thought. (more…)
Antarctica’s topography began changing from flat to fjord-filled starting about 34 million years ago, according to a new report from a University of Arizona-led team of geoscientists.
Knowing when Antarctica’s topography started shifting from a flat landscape to one with glaciers, fjords and mountains is important for modeling how the Antarctic ice sheet affects global climate and sea-level rise. (more…)
Dissolution or creation of huge gypsum deposits changed sulfate content of the oceans
Scientists have discovered a potential cause of Earth’s “icehouse climate” cooling trend of the past 45 million years. It has everything to do with the chemistry of the world’s oceans.
“Seawater chemistry is characterized by long phases of stability, which are interrupted by short intervals of rapid change,” says geoscientist Ulrich Wortmann of the University of Toronto, lead author of a paper reporting the results and published this week in the journal Science.
“We’ve established a new framework that helps us better interpret evolutionary trends and climate change over long periods of time. The study focuses on the past 130 million years, but similar interactions have likely occurred through the past 500 million years.” (more…)
PASADENA, Calif. — A new university-led study with NASA participation finds ancient Antarctica was much warmer and wetter than previously suspected. The climate was suitable to support substantial vegetation — including stunted trees — along the edges of the frozen continent.
The team of scientists involved in the study, published online June 17 in Nature Geoscience, was led by Sarah J. Feakins of the University of Southern California in Los Angeles, and included researchers from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and Louisiana State University in Baton Rouge.
By examining plant leaf wax remnants in sediment core samples taken from beneath the Ross Ice Shelf, the research team found summer temperatures along the Antarctic coast 15 to 20 million years ago were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today, with temperatures reaching as high as 45 degrees Fahrenheit (7 degrees Celsius). Precipitation levels also were found to be several times higher than today. (more…)
