Sentences with phrase «of ice sheets during»

Last Glacial Maximum (LGM)- The Last Glacial Maximum refers to the time of maximum extent of the ice sheets during the last glaciation, approximately 21 ka.

New research shows that small fluctuations in the sizes of ice sheets during the last ice age were enough to trigger abrupt climate change.

Not exact matches

Scientists may also become able to distinguish between different scenarios sooner by studying the physics of local ice - sheet changes and refining reconstructions of changes during warm periods in geological history.

The only current ice sheets are Antarctic and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice sheets are Antarctic and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Amesheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Ameriice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South Amesheet covered northern Europe and the Patagonian Ice Sheet covered southern South AmeriIce Sheet covered southern South AmeSheet covered southern South America.

Today's red deer, which recolonized Europe after the ice sheet melted about 12,000 years ago, fall into three or four distinct lineages that likely correspond to separate southern regions to which the deer had retreated during the height of the ice age, Stanton says.

Many of the glaciers that jut out into the ocean are thinning, but whether the ice sheet itself has remained stable and intact, even during warm interglacial periods, is a matter of considerable debate.

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.

By contrast, during the last ice age, hundreds of comparatively smaller icebergs broke free of the Antarctic Ice Sheet and drifted into Pine Island Bice age, hundreds of comparatively smaller icebergs broke free of the Antarctic Ice Sheet and drifted into Pine Island BIce Sheet and drifted into Pine Island Bay.

We do estimate that an area of hydrocarbon reserves twice the size of Russia was directly influenced by ice sheets during past glaciation.

That's because Schaefer and colleagues» data comes from a single point in the middle of Greenland, pointing to a range of possible scenarios of what happened in the past, including several that challenge the image of Greenland being continuously covered by an extensive ice sheet during the Pleistocene.

Research published in the July 2 issue of Nature reveals one reason our planet didn't succumb to an enveloping ice sheet during glacial ages.

The other study in Nature — led by Joerg Schaefer of Lamont - Doherty Earth Observatory and Columbia University, and colleagues — looked at a small sample of bedrock from one location beneath the middle of the existing ice sheet and came to what appears to be a different conclusion: Greenland was nearly ice - free for at least 280,000 years during the middle Pleistocene — about 1.1 million years ago.

Nevertheless, some scientists claim that ratios of oxygen isotopes in marine fossils from the east coast of the US indicate that the Antarctic ice sheet melted at least partially during the Pliocene.

Some of the variation the researchers found likely dates back to isolation of different Hermit Thrushes populations by ice sheets during the Pleistocene era, while differences between the two western groups may relate to body size, with larger birds producing lower - frequency songs.

So parts of these ice sheets, but not all, must have melted during the long - ago warm period.

To get these findings, a NASA - funded team led by Laurence Smith, chair of the geography department at UCLA, spent six days on the ice during July 2012 — directly after a record - setting ice sheet melt.

Camp Century, a United States military base built within the Greenland ice sheet in 1959, doubled as a top - secret site for testing the feasibility of deploying nuclear missiles from the Arctic during the Cold War.

For example, it says a sudden methane release from the ocean, or a slowdown of the Gulf Stream, are «very unlikely» and that a collapse of the West Antarctic or Greenland ice sheets during this century is «exceptionally unlikely.»

«What we found was that during most of the deglaciation, the surface mass balance of the Laurentide Ice Sheet was generally positive,» Ullman said.

A new study has found that the massive Laurentide ice sheet that covered Canada during the last ice age initially began shrinking through calving of icebergs, and then abruptly shifted into a new regime where melting on the continent took precedence, ultimately leading to the sheet's demise.

Better estimates of Pliocene sea levels will help geologists know how much of the ice sheets melted during that balmy era, Dowsett says, which may give us a glimpse of our own climate future.

They were blocked during the LGM due to the coalescence of ice sheets from the northern Rockies (the Cordilleran Ice Sheet) and north - central Canada (the Laurentide Ice Sheet), which cut off access to both the coast and interior of northwest North America, Hoffecker saice sheets from the northern Rockies (the Cordilleran Ice Sheet) and north - central Canada (the Laurentide Ice Sheet), which cut off access to both the coast and interior of northwest North America, Hoffecker saIce Sheet) and north - central Canada (the Laurentide Ice Sheet), which cut off access to both the coast and interior of northwest North America, Hoffecker saIce Sheet), which cut off access to both the coast and interior of northwest North America, Hoffecker said.

During a record melting jag this past summer, the Greenland ice sheet lost 552 billion tons (19 billion tons lower than the previous low), and the volume of sea ice fell to half the volume it had four years ago.

According to the team's data, ice advanced from the Aurora Basin and retreated back again at least 11 times during the first 20 million years of the ice sheet's history.

One major influence is the slow rebound of crust that was weighed down by massive ice sheets during the last ice age that have since melted away.

The data they collected during low - altitude flights sketched a picture of the ice sheet's internal structure and the Gamburtsev Mountains below.

During the last ice age, much of North America was covered by a giant ice sheet that many scientists believe underwent several catastrophic collapses, causing huge icebergs to enter the North Atlantic — phenomena known as Heinrich events.

The team in today's study were able to determine that the ice sheet had partially melted during this «stable» period by analysing the chemical content of mud in sediments.

«During the last ice age around 20,000 years ago, large parts of Canada were covered by an ice sheet.

Some scientists have argued that Earth's crust in northern portions of North America is still slowly springing upward in response to the melting of the ice sheet that smothered the region during the last ice age.

«By processing the historical archive acquired by the Danish during the last century, they were able to provide an estimation of the ice sheet contribution to sea - level rise since 1900, which was critically missing in the last IPCC report,» noted Jeremie Mouginot, a climate scientist at the University of California, Irvine.

A team from Rutgers University and the University of Georgia, led by Asa Rennermalm of Rutgers, measures meltwater runoff from the ice sheet margin in Greenland during summer 2013.

Professor Richard Pancost from the University of Bristol Cabot Institute, added: «When we account for the influence of the ice sheets, we confirm that the Earth's climate changed with a similar sensitivity to overall forcing during both warmer and colder climates.»

Some scientists believe the ice sheet experienced significant melting during the relatively warmer conditions of the Pliocene, while others think it has remained almost entirely frozen for the last 14 million years.

But the large volumes of data on Arctic sea and land ice that IceBridge has collected during its nine years of operations there have also enabled scientific discoveries ranging from the first map showing what parts of the bottom of the massive Greenland Ice Sheet are thawed to improvements in snowfall accumulation models for all of Greenlaice that IceBridge has collected during its nine years of operations there have also enabled scientific discoveries ranging from the first map showing what parts of the bottom of the massive Greenland Ice Sheet are thawed to improvements in snowfall accumulation models for all of GreenlaIce Sheet are thawed to improvements in snowfall accumulation models for all of Greenland.

By offering support for the idea that the EAIS has been largely stable during the last 14 million years, the research offers some hope that a massive collapse of the ice sheet, and associated sea level rise of tens of meters, may not be imminent.

The study's authors found that in the last 30 years of the study, the ice sheet gained nearly 5 meters (16 feet) more water than it did during the first 30 years of the studied time period.

«Based on the likely location of ice deposits during this period of Mars» history, and the amount of meltwater that could have been produced by Lyot ejecta landing on an ice sheet, we think this is the most plausible scenario for the formation of these valleys» said David Weiss, a recent Ph.D. graduate from Brown and the study's lead author.

The Cordilleran Ice Sheet covered large parts of North America during the Pleistocene - or last ice age - and was similar in mass to the Greenland Ice SheIce Sheet covered large parts of North America during the Pleistocene - or last ice age - and was similar in mass to the Greenland Ice Sheice age - and was similar in mass to the Greenland Ice SheIce Sheet.

In a study out of the University of Arizona, researchers found that melting ice sheets had a greater impact on sea level rise than the thermal expansion of the oceans during the previous interglacial period 125,000 years ago.

They calculated that the ice sheet contributed at least an inch of sea level rise during the 20th century, or somewhere between 10 and 17 percent of the total.

Launched in January 2013, Planet Four is a Zooniverse citizen science project enlisting members of the general public to help study dark blotches and fans that appear on top of the Martian South Pole's thawing carbon dioxide ice sheet during the Southern Spring and Summer.

During the last deglaciation, and likely also the three previous ones, the onset of warming at both high southern and northern latitudes preceded by several thousand years the first signals of significant sea level increase resulting from the melting of the northern ice sheets linked with the rapid warming at high northern latitudes (Petit et al., 1999; Shackleton, 2000; Pépin et al., 2001).

However, it does say that if the collapse is underway, the contribution of ice sheets would not «exceed several tenths of a metre during the 21st century».

During periods of West Antarctic Ice Sheet absence, the Antarctic Peninsula Ice Sheet remained as a series of island ice caps, and was also a refuge for plants and animals [2, 18, 1Ice Sheet absence, the Antarctic Peninsula Ice Sheet remained as a series of island ice caps, and was also a refuge for plants and animals [2, 18, 1Ice Sheet remained as a series of island ice caps, and was also a refuge for plants and animals [2, 18, 1ice caps, and was also a refuge for plants and animals [2, 18, 19].

are now thought of as inaccurate because the lower layers of the ice sheet have become buckled and jumbled up However, at least one major cold and dry event during the Eemian seems to be corroborated by the terrestrial pollen record from Europe and China (Zhisheng & Porter 1997).

During my last two months at Headquarters, management became concerned with the coming demise of the laser altimeter measurements of the ice sheets begun in 2003 by the ICESat satellite, which ceased operation on October 11 of this year.

During that time, which can last hundreds to thousands of years, glaciers and ice sheets expand in size and depth.

Matthias Kuhle's geological theory of Ice Age development was suggested by the possible existence of an ice sheet covering the Tibetan plateau during the Ice AgIce Age development was suggested by the possible existence of an ice sheet covering the Tibetan plateau during the Ice Agice sheet covering the Tibetan plateau during the Ice AgIce Ages.

Ice sheets that form during glaciations cause erosion of the land beneath them.