Sentences with phrase «ice sheet mass loss»
Ocean warming near the Antarctic ice shelves has critical implications for future ice sheet mass loss and global sea level rise.
https://www.gfdl.noaa.gov/
However, detecting acceleration is difficult because of (i) interannual variability in GMSL largely driven by changes in terrestrial water storage (TWS)(7 ⇓ — 9), (ii) decadal variability in TWS (10), thermosteric sea level, and ice sheet mass loss (11) that might masquerade as a long - term acceleration over a 25 - y record, (iii) episodic variability driven by large volcanic eruptions (12), and (iv) errors in the altimeter data, in particular, potential drifts in the instruments over time (13).
Because of changes in Earth's gravity field resulting from ice sheet mass loss, ocean sea level will actually drop near the areas of melt and rise elsewhere.
The Washington Post asks Ian Joughin about a recent study, in the journal Science Advances, using a GPS network which measures ice sheet mass loss in Greenland and re-evaluates previous studies.
Estimates of the decadal variability in ice sheet mass loss (11) suggest the impact on acceleration estimates is ∼ 0.014 mm / y2 for a 25 - y time series, in the absence of rapid dynamical changes in the ice sheets.
This large acceleration explains a large share of the different GRACE estimates of ice sheet mass loss published in recent years.
«Our results confirm a decline in the relative importance of discharge to ice sheet mass loss (Figure 3).
The corresponding increased ice sheet mass loss has often followed thinning, reduction or loss of ice shelves or loss of floating glacier tongues.
... what are the shapes of the ice sheet mass loss curves for Greenland and West Antarctica?
We argue that ice sheets in contact with the ocean are vulnerable to non-linear disintegration in response to ocean warming, and we posit that ice sheet mass loss can be approximated by a doubling time up to sea level rise of at least several meters.
The modest increase in ice discharge over the past 7 years is contrasted by high rates of ice sheet mass loss and distinct spatial patters of elevation lowering.
To say nothing of the warming trends also noticed in, for example: * ocean heat content * wasting glaciers * Greenland and West Antarctic ice sheet mass loss * sea level rise due to all of the above * sea surface temperatures * borehole temperatures * troposphere warming (with stratosphere cooling) * Arctic sea ice reductions in volume and extent * permafrost thawing * ecosystem shifts involving plants, animals and insects
Our atmosphere - ocean model shows that the freshwater spurs amplifying feedbacks that would accelerate ice shelf and ice sheet mass loss, thus providing support for our assumption of a nonlinear ice sheet response.
If ice sheet disintegration reaches a point such that the dynamics and momentum of the process take over, at that point reducing greenhouse gases may be unable to prevent major ice sheet mass loss, sea level rise of many meters, and worldwide loss of coastal cities — a consequence that is irreversible for practical purposes.
For example, if ice sheet mass loss becomes rapid, it is conceivable that the cold fresh water added to the ocean could cause regional surface cooling [199], perhaps even at a point when sea level rise has only reached a level of the order of a meter [200].
The critical issue is whether human - spurred ice sheet mass loss can be approximated as an exponential process during the next few decades.
Southern Ocean surface cooling, while lower latitudes are warming, increases precipitation on the Southern Ocean, increasing ocean stratification, slowing deepwater formation, and increasing ice sheet mass loss.
For Antarctica as a whole, the study found the current rate of ice sheet mass loss to be about 160 billion metric tons of ice per year.
«The most reliable indication of the imminence of multi-meter sea level rise may be provided by empirical evaluation of the doubling time for ice sheet mass loss.»
There is no closure if you also add to thermosteric rise and ice sheet mass loss that groundwater estimate.
But again the «models» estimate includes an observed ice sheet mass loss term of 0.41 mm / year whereas ice sheet models give a mass gain of 0.1 mm / year for this period; considering this, observed rise is again 50 % faster than the best model estimate for this period.
This is despite using observed ice sheet mass loss (0.19 mm / year) in the «modelled» number in this comparison, otherwise the discrepancy would be even larger — the ice sheet models predict that the ice sheets gain mass due to global warming.
If ice sheet disintegration reaches a point such that the dynamics and momentum of the process take over, at that point reducing greenhouse gases may be unable to prevent major ice sheet mass loss, sea level rise of many meters, and worldwide loss of coastal cities — a consequence that is irreversible for practical purposes.
His comments are based on the paper «Limits in detecting acceleration of ice sheet mass loss due to climate variability», B. Wouters, J. L. Bamber, M. R. van den Broeke, J. T. M. Lenaerts and I. Sasgen, Nature Geoscience 6, 613 — 616 (2013) doi: 10.1038 / ngeo1874 Find the abstract and illustrations for that paper here.
Cordilleran Ice Sheet mass loss responded to climate reversals near the Pleistocene Termination
Without the moderating effects of increased snowfall and refreezing, post-1996 Greenland ice sheet mass losses would have been 100 % higher.
CryoSat - 2 observations taken between November 2010 and September 2013 indicate annual ice sheet mass losses of 134 ± 27 gigatons in West Antarctica, 3 ± 36 gigatons in East Antarctica, and 23 ± 18 gigatons on the Antarctic Peninsula.
Not exact matches
As glaciologist Richard Alley of Pennsylvania State University notes: «The ice sheet is losing mass, this loss has increased over time, [and] it is not the dominant term in sea - level rise — but it matters.»
The drought that is devastating California and much of the West has dried the region so much that 240 gigatons worth of surface and groundwater have been lost, roughly the equivalent to a 3.9 - inch layer of water over the entire West, or the annual loss of mass from the Greenland Ice Sheet, according to the study.
«By refining the spatial pattern of mass loss in the world's second largest — and most unstable — ice sheet, and learning how that pattern has evolved, we are steadily increasing our understanding of ice loss processes, which will lead to better - informed projections of sea level rise.»
«It doesn't change our estimates of the total mass loss all over Greenland by that much, but it brings a more significant change to our understanding of where within the ice sheet that loss has happened, and where it is happening now.»
«Once you have that combination of ocean heat and atmospheric heat — which are related — that's when the ice sheet could really experience dramatic ice mass loss.»
In other words, the losses of mass of the West Antarctic Ice Sheet will intensify — just like the models predict.»
The melting of Greenland contributes to the global sea level, but the loss of mass also means that the ice sheet's own gravitational field weakens and thus does not attract the surrounding sea as strongly.
«The fact that the mass loss of the Greenland Ice Sheet has generally increased over the last decades is well known,» Khan said, «but the increasing contribution from the northeastern part of the ice sheet is new and very surprising.&raqIce Sheet has generally increased over the last decades is well known,» Khan said, «but the increasing contribution from the northeastern part of the ice sheet is new and very surprising.&rSheet has generally increased over the last decades is well known,» Khan said, «but the increasing contribution from the northeastern part of the ice sheet is new and very surprising.&raqice sheet is new and very surprising.&rsheet is new and very surprising.»
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.
Subtracting one from the other produced a «mass - balance» picture of net ice loss or growth for each ice sheet.
«At the same time, the mass loss on the ice sheet is not very large compared to how much mass they store.»
Despite being trumpeted in certain circles as meaning that there's really nothing to worry about regarding the Greenland ice sheet, the authors made a point of noting (although not in this press release) that an additional source of mass loss needs to be identified in order to reconcile their results with the GRACE data (which do not show a reduction in mass loss for the same period).
First, the loss of mass in the Antarctic ice sheet is actually somewhat unexpected.
The relevant papers are [Velicogna and Wahr 2006 Measurements of time - variable gravity show mass loss in Antarctica Science 311, 1754 - 1756 and Rignot and Thomas «Mass balance of polar ice sheets» Science 297, 1502 - 1506]
A large contribution from the Greenland Ice Sheet is unlikely, as it is mostly grounded above sea level and so mass loss from calving ice bergs is limitIce Sheet is unlikely, as it is mostly grounded above sea level and so mass loss from calving ice bergs is limitice bergs is limited.
The reconstructed curve includes isolated rapid events of several decimetres within a few centuries, one of which is most likely related to loss from the Antarctic ice sheet mass around 5000 years before present.
Joughin et al. (2010) applied a numerical ice sheet model to predicting the future of PIG, their model suggested ongoing loss of ice mass from PIG, with a maximum rate of global sea level rise of 2.7 cm per century.
In the figure right, from Rignot et al. 2008, you can see that mass losses from Pine Island Glacier and Thwaites Glacier dominate Antarctic Ice Sheet ice lossIce Sheet ice lossice losses.
The IPCC projects that ice mass loss from melting of the Greenland ice sheet will continue to outpace accumulation of snowfall.
The Greenland, and possibly the Antarctic, ice sheets have been losing mass recently, because losses by ablation including outlet glaciers exceed accumulation of snowfall.
Our modelled values are consistent with current rates of Antarctic ice loss and sea - level rise, and imply that accelerated mass loss from marine - based portions of Antarctic ice sheets may ensue when an increase in global mean air temperature of only 1.4 - 2.0 deg.
Our experiments show a clear threshold in the relationship between the rate of sea - level rise, and the rate of (sea - level contributing) ice - sheet mass loss.
From recent instrumental observations alone we are therefore unable to predict whether mass loss from these ice sheets will vary linearly with changes in the rate of sea - level rise, or if a non-linear response is more likely.