Sentences with phrase «ice sheet changed at»

The project used satellite and aerial data from NASA to reconstruct how the height of the Greenland Ice Sheet changed at nearly 100,000 locations from 1993 to 2012.

In December 2014, for example, she and colleagues published a study that used NASA satellite and aerial data to reconstruct how the height of the Greenland Ice Sheet changed at nearly 100,000 locations from 1993 to 2012.

Not exact matches

Understanding sea level change in relation to the mass balance of Greenland's and Antarctica's ice sheets is at the heart of the CReSIS mission.

Mote was one of 12 lead authors on a chapter of the fifth Intergovernmental Panel on Climate Change report looking at the cryosphere, which is comprised of snow, river and lake ice, sea ice, glaciers, ice sheets and frozen ground.

Estimated changes in the mass of Greenland's ice sheet suggest it is melting at a rate of about 239 cubic kilometres (57.3 cubic miles) per year.

«Time and again, the models are conservative, and they're underestimating the magnitude of change,» says Robert DeConto, an ice sheet modeler at the University of Massachusetts Amherst.

Using NASA and European Space Agency satellites, the 2015 study had measured the changing height of the ice sheet and determined that East Antarctica was ballooning upward by roughly 1.59 centimeters a year (at least from 1992 to 2001 and from 2003 to 2008).

The digitized data extend the record of changes at the bottom of the ice sheet, such as the formation of channels as Antarctica's ice flows, by more than two decades.

Today, as warming waters caused by climate change flow underneath the floating ice shelves in Pine Island Bay, the Antarctic Ice Sheet is once again at risk of losing mass from rapidly retreating glacieice shelves in Pine Island Bay, the Antarctic Ice Sheet is once again at risk of losing mass from rapidly retreating glacieIce Sheet is once again at risk of losing mass from rapidly retreating glaciers.

«It is a very good paper which provides valuable new insights about the physical processes controlling the change in reflectivity of the Greenland ice sheet and specifically its darkening over time,» said Eric Rignot, a senior research scientist at NASA's Jet Propulsion Laboratory who studies ice sheets but was not involved with the new study.

Co-author Professor Jonathan Bamber, based at the University of Bristol, and President of the European Geoscience Union (EGU), added: «We are seeing changes in the large - scale circulation patterns, which leads to more frequent sunshine and higher amounts of solar energy reaching the surface of the ice sheet.

New research indicates that climate change has triggered an unstoppable decay of the West Antarctic Ice Sheet, eventually leading to at least three meters of global sea level rise

A report in the last issue of Nature finds that between April 2002 and April 2006, the rate at which southern Greenland's ice liquefied jumped by 250 percent — supporting the idea that the Greenland ice sheet responds quickly to slight changes in climate.

While some may see evidence of rapid glacier thinning in the past and again today as evidence that the West Antarctic Ice Sheet is nearing a collapse driven by human - caused climate change, Steig said at this point, scientists just don't know whether that is the case.

Although CryoSat - 2 is designed to measure changes in the ice sheet elevation, these can be translated into horizontal motion at the grounding line using knowledge of the glacier and sea floor geometry and the Archimedes principle of buoyancy — which relates the thickness of floating ice to the height of its surface.

The widespread melting across the Greenland ice sheet was one of the most dramatic changes, said Jason Box of the Byrd Polar Research Center at Ohio State University in Columbus.

At the end of an ice age continental ice sheets, oceans and atmosphere change rapidly.

«This is probably the best method to look at mass changes of ice sheets if you want to get a number that you can trust,» Rignot says.

That blind spot comes at a time when ice sheets in West Antarctica and Greenland are changing more quickly than anyone expected.

At the heart of man - made climate change, Greenland's ice sheet is both stunning and fragile when seen from the air.

What's left to figure out is whether this is happening with other subglacial lakes around the Greenland ice sheet, as well as whether and how to incorporate the findings into models that are aimed at gauging how much Greenland might change with the warming climate and how much water it could add to the rising seas.

«The effort to use the old photographs to learn how the margins of the ice sheet have changed is wonderful,» said Richard Alley, a glaciologist at Pennsylvania State University.

Carys Cook, co-author and research postgraduate from the Grantham Institute for Climate Change at Imperial, adds: «Scientists previously considered the East Antarctic ice sheet to be more stable than the much smaller ice sheets in West Antarctica and Greenland, even though very few studies of East Antarctic ice sheet have been carried out.

A new study by scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, and the University of California, Irvine, shows that while ice sheets and glaciers continue to melt, changes in weather and climate over the past decade have caused Earth's continents to soak up and store an extra 3.2 trillion tons of water in soils, lakes and underground aquifers, temporarily slowing the rate of sea level rise by about 20 percent.

BANGLADESH is one of the countries at most risk from climate change, as it is low - lying and could be swamped by rising seas — particularly if they rise by several metres (see «Ice sheets on course for collapse «-RRB-.

But that could soon change, Rignot said, because the rate at which ice sheets are losing mass is increasing three times faster than the rate of ice loss from mountain glaciers and ice caps.

The study, co-authored by Dr Thomas Stevens, from the Department of Geography at Royal Holloway, University of London, found a previously unknown mechanism by which the joining of North and South America changed the salinity of the Pacific Ocean and caused major ice sheet growth across the Northern Hemisphere.

«With something like the Antarctic ice sheet, some of these processes take centuries, and the amount of time we've been able to observe changes is at the maximum 20 years,» Bingham said.

«Certainly that is the one that is setting off all the alarms if you look at recent changes in ice sheets.

Using 50 million laser readings from a NASA satellite, scientists for the first time calculated changes in the height of the vulnerable but massive ice sheets and found them especially worse at their edges.

Ash was part of Expedition 374, which spent 46 days at sea this year to study the evolution of the Ross Sea ice sheet off West Antarctica and the relationship between climatic and oceanic change through the Neogene and Quaternary periods, from 23 million years ago to the present day.

«The big question is whether the ice sheet will react to these changing ocean conditions as rapidly as it did 14,000 years ago,» said lead author Dr Nick Golledge, a senior research fellow at Victoria's Antarctic Research Centre.

It's the fast - moving ice that determines how the ice sheet responds to climate change on a short timescale,» said Robert Bindschadler, a NASA scientist at the Goddard Space Flight Centre in Maryland, one of the study's co-authors.

The space agency is launching these missions at a time when decades of observations from the ground, air, and space have revealed signs of change in Earth's ice sheets, sea ice, glaciers, snow cover and permafrost.

He told the Climate News Network: «While the sparse existing observations do not indicate warmer water inflow towards the Wilkes ice sheet margin at present, there is no reason why changes similar to those in West Antarctica could not also occur here.»

Huybrechts, P., 2002: Sea - level changes at the LGM from ice - dynamics reconstructions of the Greenland and Antarctic ice sheets during the glacial cycles.

Our new study, published today in the journal Earth's Future, finds that — at least from measurements of global sea level and continental - scale Antarctic ice - sheet changes — scientists won't be able to tell which road the planet is on until the 2060s.

That estimate was based in part on the fact that sea level is now rising 3.2 mm / yr (3.2 m / millennium)[57], an order of magnitude faster than the rate during the prior several thousand years, with rapid change of ice sheet mass balance over the past few decades [23] and Greenland and Antarctica now losing mass at accelerating rates [23]--[24].

So does mass change at the Earth's surface, which can come from shifts in ice sheets, or even possibly in major atmospheric wind currents.

The typical estimate of the sea - level change is five metres, a value arrived at by taking the total volume of the West Antarctic Ice Sheet, converting it to water and spreading it evenly across the oceans.

... Polar amplification explains in part why Greenland Ice Sheet and the West Antarctic Ice Sheet appear to be highly sensitive to relatively small increases in CO2 concentration and global mean temperature... Polar amplification occurs if the magnitude of zonally averaged surface temperature change at high latitudes exceeds the globally averaged temperature change, in response to climate forcings and on time scales greater than the annual cycle.

Among the ice sheet dynamics to fret about I see this change in the temperature of the ice from say -30 C to ice - at - 0C and the subsequent uptake of the heat to go from ice - at - 0C to water - at - 0C as the «dark matter» of the cryosphere.

Robert Bindschadler of NASA and Tad Pfeffer at the University of Colorado, both glacier specialists, told me that they saw scant evidence that a yards - per - century rise in seas could be produced from the ice sheets that currently cloak Greenland and West Antarctica, which are very different than what existed in past periods of fast sea - level changes.

What is still contentious is what the result implies for the YD climate change and the megafaunal extinctions, incorporating the ideas of both the broad large scale cometary debris impact scenario at low grazing angles, and the direct asteroidal impact into water and ice covered surfaces, and all that implies with the ice sheet disruptions, megatsunamis and the ozone layer and atmospheric effects and disruption that are possible in these events.

Also: researchers see new changes at the poles — from slippery ice sheets to mysterious gasses.

In probing the fast - changing ice sheets of Antarctica and Greenland, Gordon Hamilton of the University of Maine exemplified the qualities in the rare breed of scientists, engineers and field staff willing to go to extremes — literally — to help clarify the pace at which seas will rise as warming glacial ice melts.

In LGM simulations land albedo changes are prescribed (at least in regards to ice sheets and altered topography due to sea level; there are feedback land albedo changes) so are a forcing, whereas sea ice is determined interactively by the model climate, so is a feedback in this framework.

Other forcings, including the growth and decay of massive Northern Hemisphere continental ice sheets, changes in atmospheric dust, and changes in the ocean circulation, are not likely to have the same kind of effect in a future warming scenario as they did at glacial times.

We have fairly high confidence that we observe the history of Heinrich events (huge discharges of ice - rafted debris from the Laurentide ice sheet through Hudson Bay that are roughly coincident with large southern warming, southward shift of the intertropical convergence zone, extensive sea ice in the north Atlantic, reduced monsoonal rainfall in at least some parts of Asia, and other changes), and also cold phases of the Dansgaard / Oeschger oscillations that lack Heinrich layers and are characterized by muted versions of the other climate anomalies I just mentioned.

The biggest change is that ice sheet dynamics look more uncertain now than at the time of the TAR, which is why this uncertainty is not included any more in the cited range but discussed separately in the text.