Sentences with phrase «ice sheet model which»

Kuhn, from Germany's Alfred Wegener Institute, added, «This gives confidence in the predictions of the current generation of ice sheet models which are used to forecast future ice loss from Antarctica and resulting sea - level rise.»

Not exact matches

This gives confidence in the predictions of the current generation of ice - sheet models which are used to forecast future ice loss from Antarctica and resulting sea - level rise.»

Surprise find The team's actual mission was to survey ocean currents near the Ross Ice Shelf, a slab of ice extending more than 600 miles (970 kilometers) northward from the grounding zone of the West Antarctic Ice Sheet into the Ross Sea, to model the behavior of a drill string, a length of pipe extending to the seafloor which delivers drilling fluids and retrieves sediment samplIce Shelf, a slab of ice extending more than 600 miles (970 kilometers) northward from the grounding zone of the West Antarctic Ice Sheet into the Ross Sea, to model the behavior of a drill string, a length of pipe extending to the seafloor which delivers drilling fluids and retrieves sediment samplice extending more than 600 miles (970 kilometers) northward from the grounding zone of the West Antarctic Ice Sheet into the Ross Sea, to model the behavior of a drill string, a length of pipe extending to the seafloor which delivers drilling fluids and retrieves sediment samplIce Sheet into the Ross Sea, to model the behavior of a drill string, a length of pipe extending to the seafloor which delivers drilling fluids and retrieves sediment samples.

Dr Ian Joughin at the University of Washington, author of a recent study simulating future Antarctic ice sheet losses added: «This study does a nice job of revealing the strong thinning along the Amundsen Coast, which is consistent with theory and models indicating this region is in the early stages of collapse.»

The consequences of global sea level rise could be even scarier than the worst - case scenarios predicted by the dominant climate models, which don't fully account for the fast breakup of ice sheets and glaciers, NASA scientists said today (Aug. 26) at a press briefing.

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.

Experiments of this type are however challenging as ice sheets evolve over multi-millennial timescales, which is beyond the practical integration limit of most Earth system models.

And it is inspiring to see such progress being made in the detail with which models of ice sheet dynamics and other forms of change can be applied to the moderately far future.

For example, how much confidence can we really have in results from ice sheet models, which very likely miss important mechanisms (e.g., due to limited understanding of ocean - ice shelf interactions, calving physics and influence of small - scale topography)?

And were the models earlier (say 10 years ago) predicting the current speed at which the Greenland ice sheets are melting?

This result would be strongly dependent on the exact dynamic response of the Greenland ice sheet to surface meltwater, which is modeled poorly in todays global models.Yes human influence on the climate is real and we might even now be able to document changes in the behavior of weather phenomena related to disasters (e.g., Emanuel 2005), but we certainly haven't yet seen it in the impact record (i.e., economic losses) of extreme events.

What this model shows is that if orbital variations in insolation impact ice sheets directly in any significant way (which evidence suggests they do Roe (2006)-RRB-, then the regression between CO2 and temperature over the glacial - interglacial cycles (which was used in Snyder (2016)-RRB- is a very biased (over) estimate of ESS.

This result would be strongly dependent on the exact dynamic response of the Greenland ice sheet to surface meltwater, which is modeled poorly in todays global models.

Combined climate / ice sheet model estimates in which the Greenland surface temperature was as high during the Eemian as indicated by the NEEM ice core record suggest that loss of less than about 1 m sea level equivalent is very unlikely (e.g. Robinson et al. (2011).

Well it depends on whether you are talking about Climate Sensitivity (Charney sensitivity... which is modelled) or Earth System Sensitivity (where things like ice sheet extent, vegetation cover etc are regarded as able to respond quickly to warming).

«Beyond 2 degrees you risk potentially catastrophic impacts such as a destabilization of the polar land - based ice sheets that would have very severe economic consequences which are not present in the economic models,» Ward at LSE said.

These authors use an ice sheet model within a Bayesian statistical framework — in which critical processes are guided by expert synthesis — to simulate the mass loss from the entire Antarctic ice sheet to 2200.

In the new study, Csatho's team found areas of rapid shrinkage in southeast Greenland that current climate models don't address, which suggests the ice sheet may lose ice more rapidly in the near future than previously thought.

Arctic air temperatures are increasing at twice the rate of the rest of the world — a study by the U. S. Navy says that the Arctic could lose its summer sea ice by next year, eighty - four years ahead of the models — and evidence little more than a year old suggests the West Antarctic Ice Sheet is doomed, which will add between twenty and twenty - five feet to ocean leveice by next year, eighty - four years ahead of the models — and evidence little more than a year old suggests the West Antarctic Ice Sheet is doomed, which will add between twenty and twenty - five feet to ocean leveIce Sheet is doomed, which will add between twenty and twenty - five feet to ocean levels.

One of the most feared of all model - based projections of CO2 - induced global warming is that temperatures will rise to such a degree as to cause a disastrous melting / destabilization of the Greenland Ice Sheet (GrIS), which melting is subsequently projected to raise global sea level by several meters.

«Models traditionally have projected that this difference doesn't become negative (i.e. net loss of Antarctic ice sheet mass) for several decades,» Mann said, adding that detailed gravimetric measurements, which looks at changes in Earth's gravity over spots to estimate, among other things, ice mass.

Simulating the variation of the ice sheet's albedo using a regional climate model — Modèle Atmosphérique Régionale (MAR), which some members of the team helped develop — indicated that increasing temperatures and melting accompanied by snow grain growth and greater bare ice exposure account for about half the decline, the scientists report.

The biggest scientific contribution that Hansen and his colleagues make is an attempt to nail down a Moore's law (which models nonlinear rates of growth in computer chips) to ice sheets: Assuming non-linear processes have already begun, how fast will Greenland and Antarctica melt?

And older climate models did not include dynamic ice sheet vulnerabilities — like high latent - heat ocean water coming into contact with the submerged faces of sea - fronting glaciers, the ability of surface melt water to break up glaciers by pooling into cracks and forcing them apart (hydrofracturing), or the innate rigidity and frailty of steep ice cliffs which render them susceptible to rapid toppling.

But in Bamber's second calculation the relatively sophisticated energy balance model, which he believes better represents ice sheet behaviour, gave a threshold of 8 degrees for irreversible melting of Greenland — double the previously published threshold.

Despite higher temperature change projections in this assessment, the sea level projections are slightly lower, primarily due to the use of improved models which give a smaller contribution from glaciers and ice sheets.

But in Bamber's second calculation the relatively sophisticated energy balance model, which he believes better represents ice sheet behaviour, gave a threshold of 8 degrees for irreversible melting of Greenland - double the previously published threshold.

But «These models can not explain the high sea levels in the Pliocene period [from 5.3 million to 2.5 million years ago, which began warm and with high sea levels, but cooled towards the end], for example, where data point at a less stable Antarctic ice sheet than in the current models.»

We refer to both the one - dimensional ice sheet modelling of de Boer et al. [46], which was used to calculate sea level for the entire Cenozoic era, and the three - dimensional ice sheet model of Bintanja et al. [59], which was used for simulations of the past million years.

Hansen [49,50] argues that real ice sheets are more responsive to warming than in most ice sheet models, which suggests that large ice sheets are relatively stable.

Sea level from equations (3.3) and (3.4) is shown by the blue curves in figure 2, including comparison (figure 2c) with the Late Pleistocene sea - level record of Rohling et al. [47], which is based on analysis of Red Sea sediments, and comparison (figure 2b) with the sea - level chronology of de Boer et al. [46], which is based on ice sheet modelling with the δ18O data of Zachos et al. [4] as a principal input driving the ice sheet model.

The large temperature change may be required to produce substantial sea - level change in their ice sheet model, which we suggested above is unrealistically unresponsive to climate change.

It is such «moderate» sea - level change for which we particularly question the projections implied by current ice sheet models.

These simulations show a global cooling of approximately 3.5 °C to 5.2 °C when LGM greenhouse gas and ice sheet boundary conditions are specified (Chapter 6), which is within the range -LRB--- 1.8 °C to — 6.5 °C) of PMIP results from simpler models that were discussed in the TAR (McAvaney et al., 2001).

Dynamical processes related to ice flow — which are not included in current models but suggested by recent observations — could increase the vulnerability of the ice sheets to warming, increasing future sea level rise.

How can you discuss the topic of future warming commitment based on AR4 models which totally neglect the real driver of future warming, namely ice - sheet responses?

The «boils» are also a dynamic effect which computer models of heated water pots might have missed — similar to ice sheet dynamics.

Such solecisms throughout the IPCC's assessment reports (including the insertion, after the scientists had completed their final draft, of a table in which four decimal points had been right - shifted so as to multiply tenfold the observed contribution of ice - sheets and glaciers to sea - level rise), combined with a heavy reliance upon computer models unskilled even in short - term projection, with initial values of key variables unmeasurable and unknown, with advancement of multiple, untestable, non-Popper-falsifiable theories, with a quantitative assignment of unduly high statistical confidence levels to non-quantitative statements that are ineluctably subject to very large uncertainties, and, above all, with the now - prolonged failure of TS to rise as predicted (Figures 1, 2), raise questions about the reliability and hence policy - relevance of the IPCC's central projections.

But one modeling study put the threshold level for the eventual near - complete loss of Greenland's ice sheet at a local warming of just 2.7 C — which, due to Arctic amplification, means a global warming of only 1.2 C. Total melting of Greenland — luckily, something that would likely take centuries — would raise sea levels by 7 meters, submerging Miami and most of Manhattan, as well as large chunks of London, Shanghai, Bangkok and Mumbai.

Researchers hope to incorporate all of these factors into computer models of ice sheets, which still struggle to mimic how real ice sheets respond to climate change.