Sentences with phrase «marine ice sheets»

The experiment would be the first fully coupled global simulation to include dynamic ice shelf — ocean interactions for addressing the potential instability associated with grounding line dynamics in marine ice sheets around Antarctica.

«There's been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is under way,» Ian Joughin, a glaciologist at the University of Washington in Seattle, said in a news release about one of the studies published Monday.

The important role of ice shelves in stabilizing marine ice sheets introduces the potential for large and rapid ice - sheet shrinkage.

For example, chapter ten, «Ice melts, sea level rises,» discusses the disappearance of tropical mountain glaciers, estimates of sea level rise in the present century, estimates of its costs — the EPA estimated in 1991 that a one - meter rise would cost the US alone between $ 270 billion and $ 475 billion — evidence of past oceanic high - water marks and glacial extents, the dynamics of ice sheet disintegration, the thermal expansion of seawater, icequakes and meltponds, ice mass loss and gain in Greenland and Antarctica, the ozone hole, and the existence and significance of «marine ice sheets.»

This is because it is grounded below sea level, and marine ice sheets such as these are susceptible to rapid melting at their base.

Hindmarsh, R.C.A., and A. Jenkins, Centurial - millenial ice - rafted debris pulses from ablating marine ice sheets., Geophysical Research Letters, 28 (12), 2477 - 2480, 2001.

Hindmarsh, R.C.A., and E. Le Meur, Dynamical processes involved in the retreat of marine ice sheets, Journal of Glaciology, in press.

The first of these pathways, marine ice sheet instability, has been studied for decades, but the second, marine ice cliff instability, has only recently been considered as an important contributor to future sea level change.

It is the only marine ice sheet to have survived beyond the last ice age, and just as scientists predicted 30 years ago, the parts of it that are shrinking are those that are raked by sea currents.

It's a positive feedback cycle, a viscious loop that means that future recession of the ice stream is inevitable (see Marine Ice Sheet Instability and previous post).

Anderson, J.B. and Thomas, M.A., 1991, Marine ice sheet decoupling as a mechanism for rapid, episodic sea - level change: the record of such events and their influence on sedimentation: Sedimentary Geology, v. 70, p. 87 - 104.

Grounding line recession here could be irreversible, leading to rapid glacier thinning and recession, and sea level rise — see Marine Ice Sheet Instability.

A numerical model of interactions between a marine ice sheet and the solid earth: Application to a West Antarctic ice stream.

Marine ice sheet instability is a classic example of hysteresis.

Thus two completely independent studies, using completely different methods, both find that the early stages of marine ice sheet instability may be underway in West Antarctica.

Ice shelf collapse and glacier recession here, in front of the large ice streams such as Pine Island Glacier and Thwaites Glacier, would have potential to raise sea levels by tens of centimetres to a metre, through the process of marine ice sheet instability23.

Given that the West Antarctic Ice Sheet has a total sea level equivalent of 3.3 m1, with 1.5 m from Pine Island Glacier alone4, marine ice sheet collapse could be a significant challenge for future generations, with major changes in rates of sea level rise being possible within just the next couple of hundred years.

She has shown, in an ice sheet model with gravitationally self - consistent sea level, there is actually a sea level fall at the grounding line, which acts to stabilize against the marine ice sheet instability.

The authors herald this as the start of marine ice sheet instability.

The ice sheet in this area is grounded up to 2000 m below sea level, making it intrinsically unstable6 and susceptible to rapid melting at its base, and to rapid migration of the grounding line up the ice stream7 (see Marine Ice Sheet Instability).

A collapse of this ice shelf could lead to marine ice sheet instabilty and rapid global sea level rise.

Thus the entire 3 — 4 meters of global sea level contained in that ice sheet may be vulnerable to rapid disintegration, although arguments for stability of even this marine ice sheet have been made [94].

Take the Science paper: «Marine Ice Sheet Collapse Potentially Under Way for the Thwaites Glacier Basin, West Antarctica.»

John Mercer, in 1968 and 1970, called attention to the fact that the West Antarctic Ice Sheet (WAIS) was grounded mostly below sea level, calling it a «marine ice sheet» that was therefore inherently unstable, and proposed that the higher sea level resulted from its LIM collapse 125,000 years ago.

Marine ice sheet instability occurs when sub-shelf melt rate is large enough to force the ice sheet grounding line to retreat into an area where the ice is grounded below sea level on an inward - sloping bedrock, then it can become unstable.

Marine Ice Sheet Collapse Potentially Underway for the Thwaites Glacier Basin, West Antarctica

A study using Earth Remote Sensing satellite radar interferometry (EERS - 1 and -2) observations from 1992 through 2011 finds «a continuous and rapid retreat of the grounding lines of Pine Island, Thwaites, Haynes, Smith, and Kohler» Glaciers, and the authors conclude that «this sector of West Antarctica is undergoing a marine ice sheet instability that will significantly contribute to sea level rise in decades to centuries to come» (Rignot et al. 2014).

Joughin, I., B. E. Smith, and B. Medley (2014), Marine ice sheet collapse potentially under way for the Thwaites Glacier Basin, West Antarctica, Science, 344 (6185), 735 — 738.

A marine ice sheet is grounded on bedrock, below the surface of the sea.

Although West Antarctica's fate is sealed, we may still be able to prevent the collapse of East Antarctica's marine ice sheet.

... Most projections for the Antarctic Ice Sheet since IPCC AR5 limit the sea - level contribution as a result of dynamic discharge and the potential onset of the marine ice sheet instability to 0.3 m by the end of this century.

The decline of sea levels close to the grounding line of receding marine ice sheet has major effects on the ice sheets.

Joughin, I., Smith, B. E. & Medley, B. Marine ice sheet collapse potentially under way for the Thwaites Glacier basin, West Antarctica.

Joughin, I., B. Smith, B. Medley, Marine Ice Sheet Collapse Potentially Under Way for the Thwaites Glacier Basin, West Antarctica, Science 16 May 2014: Vol.

Not exact matches

Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet and will be updating Scientific American readers regularly.

The glacier appears to be collapsing due to marine ice - sheet instability.

Editor's note: Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet.

Editor's Note: Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet.

«We argue that it was the establishment of the modern deep ocean circulation — the ocean conveyor — about 2.7 million years ago, and not a major change in carbon dioxide concentration in the atmosphere that triggered an expansion of the ice sheets in the northern hemisphere,» says Stella Woodard, lead author and a post-doctoral researcher in the Department of Marine and Coastal Sciences.

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.

Using sediment gathered from the ocean floor in different areas of the world, the researchers were able to confirm that as the ice sheets started melting and the climate warmed up at the end of the last ice age, 18,000 years ago, the marine nitrogen cycle started to accelerate.

We did not find isotopic evidence that a global ice sheet impacted overall marine productivity.

We would think that if an ice sheet covered the oceans it would have had an impact on marine production or photosynthesis and we find no carbon isotopic evidence for this.

The West Antarctic ice sheet is a marine - based ice sheet that is mostly grounded below sea level, which makes it much more susceptible to changes in sea level and variations in ocean temperature.

The destabilization of this marine - based sector will increase sea - level rise from the Greenland Ice Sheet for decades to come.

Image of Greenland ice sheet / Hannes Grobe, Alfred Wegener Institute for Polar and Marine Research via Wikimedia Commons

Marine geologist Karin Andreassen at CAGE, the study's lead author, says the data could hold lessons for retreating ice sheets in West Antarctica and Greenland, although her team could not determine how much methane actually escaped into the atmosphere from blowouts in the distant past.

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Retreat of Pine Island Glacier controlled by marine ice - sheet instability.

A recent high - profile article stirred debate about the threat of a process known as marine ice - sheet instability in the Antarctic.