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Ancient barley took high road to China

Science Daily - Tue, 11/21/2017 - 08:52
First domesticated 10,000 years ago in the Fertile Crescent of the Middle East, wheat and barley took vastly different routes to China, with barley switching from a winter to both a winter and summer crop during a thousand-year detour along the southern Tibetan Plateau, suggests new research.

Climate changes triggered immigration to America in the 19th century, study finds

Science Daily - Tue, 11/21/2017 - 08:52
From Trump to Heinz, some of America's most famous family names and brands trace their origins back to Germans who emigrated to the country in the 19th century. Researchers have now found that climate was a major factor in driving migration from Southwest Germany to North America during the 19th century.

Antarctic landscape insights keep ice loss forecasts on the radar

Science Daily - Mon, 11/20/2017 - 11:09
New maps of a mountainous landscape under a key glacier in West Antarctica will be a valuable aid in forecasting sea level changes.

Hydrological implications of rapid global warming

Science Daily - Mon, 11/20/2017 - 10:13
Researchers studying a rapid global warming event, around 56 million years ago, have shown evidence of major changes in the intensity of rainfall and flood events. The findings indicate some of the likely implications should current trends of rising carbon dioxide and global warming continue.

A popular tool to trace Earth's oxygen history can give false positives

Science Daily - Fri, 11/17/2017 - 07:52
If someone cries 'Eureka!' because it looks like oxygen appeared in Earth's ancient atmosphere long before the body of evidence indicated, be careful. If it was a chromium isotope system reading that caused the enthusiasm, it might need to be curbed.

Structure and origins of glacial polish on Yosemite's rocks

Science Daily - Wed, 11/15/2017 - 12:38
The glaciers that carved Yosemite Valley left highly polished surfaces on many of the region's rock formations. These smooth, shiny surfaces, known as glacial polish, are common in the Sierra Nevada and other glaciated landscapes. Geologists have now taken a close look at the structure and chemistry of glacial polish and found that it consists of a thin coating smeared onto the rock as the glacier moved over it.

Geologists uncover Antarctica’s fossil forests

Science Daily - Mon, 11/13/2017 - 15:28
Prehistoric polar forests were built for survival, but were not hardy enough to live in ultra-high concentrations of atmospheric carbon dioxide. A geologist is studying the tree fossil record in Antarctica from a mass extinction 250 million years ago, looking for clues to how greenhouse gases affected plants -- then and now.

When continents break it gets warm on Earth

Science Daily - Mon, 11/13/2017 - 11:37
The concentration of carbon dioxide (CO2) in the atmosphere determines whether the Earth is in greenhouse or ice age state. Before humans began to have an impact on the amount of CO2 in the air, it depended solely on the interplay of geological and biological processes, the global carbon cycle. This study shows that the break-up of continents - also known as rifting -- contributed significantly to higher CO2 concentrations in the atmosphere.

How a 'shadow zone' traps the world's oldest ocean water

Science Daily - Fri, 11/10/2017 - 10:39
New research has revealed why the oldest water in the ocean in the North Pacific has remained trapped in a shadow zone around 2km below the sea surface for over 1000 years.

Ice sheets as large as Greenland's melted fast in a warming climate

Science Daily - Thu, 11/09/2017 - 21:40
New research shows that climate warming reduced the mass of the Cordilleran Ice Sheet by half in as little as 500 years, indicating the Greenland Ice Sheet could have a similar fate.

How ice in clouds is born: More disordered

Science Daily - Wed, 11/08/2017 - 12:18
When water droplets freeze in clouds, the structure of the ice crystal isn't necessarily the classic hexagonal snowflake structure. Rather, a more disordered ice structure forms more easily than hexagonal ice under certain cloud conditions, allowing the water droplets in clouds to turn to ice more rapidly than previously predicted. The work reconciles theoretical models of clouds with observations of freezing rates.

Cooling in high and mid-latitudes led to aridification in Northern Africa

Science Daily - Wed, 11/08/2017 - 08:24
Analyses of ancient plant leaf wax found in the sediments of the Gulf of Guinea told the researchers about rainfall in Cameroon and the central Sahel-Sahara over the past several millennia and showed a rapid aridification around 5500 years before now.

Hot news from the Antarctic underground

Science Daily - Tue, 11/07/2017 - 12:17
A new NASA study adds evidence that a geothermal heat source called a mantle plume lies deep below Antarctica's Marie Byrd Land, explaining some of the melting that creates lakes and rivers under the ice sheet. Although the heat source isn't a new or increasing threat to the West Antarctic ice sheet, it may help explain why the ice sheet collapsed rapidly in an earlier era of rapid climate change, and why it is so unstable today.

Federal climate science report for U.S. released

Science Daily - Mon, 11/06/2017 - 13:37
The newly released Climate Science Special Report describes current trends in the climate globally and for the U.S., and projects trends in temperature, precipitation, sea-level rise and Arctic sea ice for the remainder of this century.

Foraminifer shells much more susceptible to ocean acidification than previously thought

Science Daily - Thu, 11/02/2017 - 10:00
The carbonate shells of tiny marine plankton, foraminifers, are important archives of geochemical records of past climates. Now researchers have discovered that, contrary to long-standing textbook knowledge, these shells do not form as calcite, but instead, are originally formed as the metastable carbonate vaterite and only later transform into calcite. The presence of vaterite instead of calcite in these abundant organisms also means that foraminifer shells are much more susceptible to ocean acidification than has been previously thought.

New Greenland maps show more glaciers at risk

Science Daily - Wed, 11/01/2017 - 14:12
New maps of Greenland's coastal seafloor and bedrock beneath its massive ice sheet show that two to four times as many coastal glaciers are at risk of accelerated melting as had previously been thought.

Intensifying winds could increase east Antarctica's contribution to sea level rise

Science Daily - Wed, 11/01/2017 - 13:16
Totten Glacier, the largest glacier in East Antarctica, is being melted from below by warm water that reaches the ice when winds over the ocean are strong, according to research. The new findings are a cause for concern because the glacier holds more than 11 feet of sea level rise and acts as a plug that helps lock in the ice of the East Antarctic Ice Sheet.

Future volcanic eruptions could cause more climate disruption

Science Daily - Tue, 10/31/2017 - 07:48
Major volcanic eruptions in the future have the potential to affect global temperatures and precipitation more dramatically than in the past because of climate change, according to a new study.

Greenhouse gas concentrations surge to new record

Science Daily - Mon, 10/30/2017 - 13:19
Concentrations of carbon dioxide in the atmosphere surged at a record-breaking speed in 2016 to the highest level in 800,000 years, according to a new report. The abrupt changes in the atmosphere witnessed in the past 70 years are without precedent.

Bat feces: A reliable source of climate change

Science Daily - Thu, 10/26/2017 - 12:53
Isotopes found in bat guano over the last 1,200 years provide scientists with information on how the climate was and is changing.


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