sediment core – Shamskm: A site to exchange knowledge and solutions

Study Finds Ancient Warming Greened Antarctica

By Guest PostJune 20, 2012Environment, Sciencealgae, ancient warming, andrill campaign, antarctic coast, antarctic ice sheet, atmospheric water vapor, aura spacecraft, carbon dioxide, climate system, fossil, frozen continent, greened antarctica, hydrogen isotope ratio, ian raine, jung eun lee, louisiana state university, margins of antarctica, marine organisms, microscopic pores, middle miocene epoch, miocene epoch, model, modern humans, NASA, past climate, plant leaf, plant life, pollen, precipitation, ross ice shelf, sarah j feakins, sediment core, sophie warny, southern mcmurdo sound, vegetation, vegetation on antarctica, wax remnants

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…)

Study Links Past Changes in Monsoon to Major Shifts in Indian Civilizations

By Guest PostMarch 15, 2012Environmentasia, band of heavy rain, bay of bengal, camilo ponton, civilizations, climate change, cmz, core monsoon zone, dorian fuller, drilling vessel, drought, equator, eth, global warming, godavari river, harappan civilization, humid monsoon, India, indian monsoon, indian peninsula, insolation, inter tropical convergence zone, itcz, joides resolution, liviu giosan, modern agriculture, monsoon, northern hemisphere, ocean, paleo climatic information, plankton fossil, sahara desert, sediment core, solar radiation, tim eglinton, tropical forest, vegetation, whoi, zurich

A fundamental shift in the Indian monsoon has occurred over the last few millennia, from a steady humid monsoon that favored lush vegetation to extended periods of drought, reports a new study led by researchers at the Woods Hole Oceanographic Institution (WHOI). The study has implications for our understanding of the monsoon’s response to climate change.

The Indian peninsula sustains over a billion people, yet it lies at the same latitude as the Sahara Desert. Without a monsoon, most of India would be dry and uninhabitable. The ability to predict the timing and amount of the next year’s monsoon is vital, yet even our knowledge of the monsoon’s past variability remains incomplete. (more…)

New CU-led Study May Answer Long-Standing Questions About Enigmatic Little Ice Age

By Guest PostJanuary 30, 2012Environmentalps, Arctic sea ice, baffin island, bette otto bliesner, canadian arctic, China, climate feedback system, climate model, cooling effect, darren larsen, dead plant material, european glacier, feedback, gifford miller, greenland, ice, ice cap, kurt refsnider, langjökull ice cap, little ice age, london, melting icecaps, middle age, Netherlands, north atlantic ocean, norway, ocean, sea, sediment core, simulation, solar radiation, south america, thames river, tropical volcanic eruptions, volcanic aerosols, waterways, yafang zhong

A new University of Colorado Boulder-led study appears to answer contentious questions about the onset and cause of Earth’s Little Ice Age, a period of cooling temperatures that began after the Middle Ages and lasted into the late 19th century.

According to the new study, the Little Ice Age began abruptly between A.D. 1275 and 1300, triggered by repeated, explosive volcanism and sustained by a self- perpetuating sea ice-ocean feedback system in the North Atlantic Ocean, according to CU-Boulder Professor Gifford Miller, who led the study. The primary evidence comes from radiocarbon dates from dead vegetation emerging from rapidly melting icecaps on Baffin Island in the Canadian Arctic, combined with ice and sediment core data from the poles and Iceland and from sea ice climate model simulations, said Miller. (more…)

Rising Carbon Dioxide Levels at End of Last Ice Age Not Tied to Pacific Ocean, As Had Been Suspected

By Guest PostOctober 9, 2011Environmentalan mix, carbon dioxide, co2 levels, coast of southwestern oregon, continental ice sheets, david lund, deep ocean, glacial times, heat trapping greenhouse gas, irvine, john southon, last ice age, levels of atmospheric carbon dioxide, microscopic shells, oregon state university, paleoclimatologist, plankton, radiocarbon dating, reservoir of carbon during glacial times, sediment core, university of california, university of michigan, ventilation rate

ANN ARBOR, Mich.— After the last ice age peaked about 18,000 years ago, levels of atmospheric carbon dioxide rose about 30 percent. Scientists believe that the additional carbon dioxide—a heat-trapping greenhouse gas—played a key role in warming the planet and melting the continental ice sheets. They have long hypothesized that the source of the gas was the deep ocean.

But a new study by a University of Michigan paleoclimatologist and two colleagues suggests that the deep ocean was not an important source of carbon during glacial times. The finding will force researchers to reassess their ideas about the fundamental mechanisms that regulate atmospheric carbon dioxide over long time scales. (more…)

Tag Archives: sediment core

Study Finds Ancient Warming Greened Antarctica

Study Links Past Changes in Monsoon to Major Shifts in Indian Civilizations

New CU-led Study May Answer Long-Standing Questions About Enigmatic Little Ice Age

Rising Carbon Dioxide Levels at End of Last Ice Age Not Tied to Pacific Ocean, As Had Been Suspected