Sentences with phrase «ice sheet points»

Not exact matches

Which means researchers now know what to look for so that we don't also miss this vital ice sheet passing the point of no return.

«Also, since this «tipping point» was reached in the late»90s before warming really took off, it indicates that these peripheral glaciers are very sensitive and, potentially, ephemeral relative to the timescales of response of the ice sheet,» he added.

In comparison, it took the Jakobshavn Isbræ ice stream — a southwest Greenland region with a fast - moving glacier that has been a focal point of scientific examination of ice sheet melt — 150 years to retreat 35 kilometers, said Khan.

We may have already changed the ice sheets to a point that some parts of them may go, but we have the ability to stop changing it more and to adapt to what we have already done.

As an example, Howat pointed to the portion of the mosaic showing Jakobshavn Glacier, the fastest - flowing glacier in the Greenland Ice Sheet.

Ice - sheet growth, coupled with favorable changes in Earth's orbit, pushed the planet past a climatic tipping point and led to both the rapid buildup of a permanent ice sheet in the Antarctic and much larger changes in global climate, says HrIce - sheet growth, coupled with favorable changes in Earth's orbit, pushed the planet past a climatic tipping point and led to both the rapid buildup of a permanent ice sheet in the Antarctic and much larger changes in global climate, says Hrice sheet in the Antarctic and much larger changes in global climate, says Hren.

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.

Enkelmann appreciates the challenge of collecting samples here because this range has the highest peaks of any coastal mountain range and is only 20 kilometers from the Pacific Ocean, but she points out that it is a tough area to study because of the big ice sheets.

«The ice shelf generally breaks at points that are between a half and full thickness of the ice sheet from the edge,» summarises Christmann.

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.

«It was the biggest collapse of its kind up to that point, and it served to demonstrate how ice shelves regulate the movement of ice from the interior of the ice sheet to the ocean.»

Box pointed to nearly ice - sheet - wide melting on Greenland, with extensive surface melting documented for first time at the highest elevations of ice sheet, and the longest melt season since satellite observations began in 1979.

Also in the mid-1990s, another group of scientists proposed the now widely accepted mechanism for how lakes can form under glaciers: Heat radiating from Earth's interior is trapped under the thick, insulating ice sheet, and pressure from the weight of all the ice above it lowers the melting point of the ice at the bottom.

«If protective ice shelves were suddenly lost in the vast areas around the Antarctic margin where reverse - sloping bedrock (where the bed on which the ice sheet sits deepens toward the continental interior, rather than toward the ocean) is more than 1,000 meters deep, exposed grounding line ice cliffs would quickly succumb to structural failure as is happening in the few places where such conditions exist today,» the researchers point out.

«It is very plausible that the mechanism revealed by this research will push parts of the West Antarctic Ice Sheet beyond a point of no return,» said Dr Axel Timmerman, Prof of Oceanography at University of Hawaii and an IPCC lead author who has seen the paper.

He pointed to an ice core taken from East Antarctica's Lake Vostok, which lies underneath the ice sheet.

TIPPING POINT A new record of the Antarctic ice sheet's formation suggests that carbon dioxide levels in the atmosphere could soon reach a tipping point that will make the ice sheet more vulnerable to melPOINT A new record of the Antarctic ice sheet's formation suggests that carbon dioxide levels in the atmosphere could soon reach a tipping point that will make the ice sheet more vulnerable to melpoint that will make the ice sheet more vulnerable to melting.

European glaciologists drilling an ice core from the highest point of the Greenland ice sheet expect to reach bedrock, 3050 metres below, this week.

Tipping point number six — the west Antarctic ice sheet — is even scarier.

«The ice sheets are still so thick at that point that there's no way through [farther inland].»

The Knife Point Glacier, one of the range's fastest retreating ice sheets, melted three times faster between 1999 and 2015 than it did between 1966 and 1999.

«These glaciers will keep retreating for decades and even centuries to come and we can't stop it,» said lead study author Eric Rignot, a glaciologist at the University of California, Irvine, and NASA's Jet Propulsion Laboratory in Pasadena, Calif. «A large sector of the West Antarctic Ice Sheet has passed the point of no return.»

We know, however, that rapid warming of the planet increases the risk of crossing climatic points of no return, possibly setting in motion large - scale ocean circulation changes, the loss of major ice sheets, and species extinctions.

Indeed, one of the findings in the recent paper by Overpeck et al. (this weeks Science), is that even as the Greenland ice sheet melts faster than originally expected, it still won't provide sufficient meltwater forcing of the North Atlantic circulation (which is the feature of the climate system most commonly implicated in the discussion of «tipping points») to force any sort of threshold change.

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).

Those elevations effectively helped them morph two - dimensional photos into a three - dimensional picture of the ice sheet at different points in time.

They could then plug that information into models to see how much ice Greenland lost over the 20th century, as well as how that loss varied over time and at different points around the ice sheet.

Ice sheet retreat continues until a new equilibrium temperature state is reached, one determined largely by the end - point of atmospheric CO2.

Is there a triggering point beyond which a feedback process is put into action that will accelerate the disintegration of some of the ice sheets?

It is important to regard the LGM studies as just one set of points in the cloud yielded by other climate sensitivity estimates, but the LGM has been a frequent target because it was a period for which there is a lot of data from varied sources, climate was significantly different from today, and we have considerable information about the important drivers — like CO2, CH4, ice sheet extent, vegetation changes etc..

«Climate change is accelerating towards the tipping points for polar ice sheets.

«What the situation suggests for Greenland ice melt summer 2016 is some thermal erosion of the «cold content» of the snow overlying the ice sheet, meaning less heat needed to «ripen'the snow to the melting point,» Box said.

Dome A, also known as Dome Argus, is the highest point on the East Antarctic Ice Sheet and one of the coldest places on earth.

Right now, the ice sheet's surface has about 1.2 times the amount of mass than normal; at the same point in 2012, it had 1.2 times less than normal, Box said.

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.

At a certain point, the woman lets go of the wheel, dazed, allowing the car to slowly maneuver itself onto a frozen lake, the sheet of ice cracking and giving way beneath her.

Indeed, one of the findings in the recent paper by Overpeck et al. (this weeks Science), is that even as the Greenland ice sheet melts faster than originally expected, it still won't provide sufficient meltwater forcing of the North Atlantic circulation (which is the feature of the climate system most commonly implicated in the discussion of «tipping points») to force any sort of threshold change.

It must be pointed out that the ice has been thinning more appreciatively in west Greenland of late and that ice sheet melting can only contribute a moderate amount of freshwater volume each year.

We are probably already past the first Hansen tipping point, the eventual loss of the Greenland Ice Sheet.

One more point: Isn't it possible that salinity levels, in particular, are different now in the ESAS than they were about 8000 years ago in the HCO, not long after most of the ice age ice sheet melted?

The other point is that there are so few unrestricted outlets for the ice sheet, that it has to melt in place for the most part, which is a much slower process than losing volume via calving.

why not a sawtooth, characteristic of a relaxation oscillator, where something (voltage on a capacitor, ice sheet thickness) accumulates until it reaches a tipping point (neon lamp trigger voltage, basal warming), then suddenly the state changes?

NASA has said that we have passed a tipping point with the West Antarctic Ice Sheet Sheet (WAIS) and its collapse is now «unstoppable».

DR PETER COX: «If we don't do anything by about twenty thirty we could have a global warming of exceeding two degrees, and at that point it's believed the Greenland ice sheet would start to melt in a way that you wouldn't be able to stop it once it started it, it would melt.

As you correctly point out, the longer - term effects of ice sheets, etc. can amplify things further, but this could be said to be included in the uncertainty in f in Roe and Baker.

Ice sheet retreat continues until a new equilibrium temperature state is reached, one determined largely by the end - point of atmospheric CO2.

We analysed what was in the report quite carefully at the time and pointed out that the allowance for dynamic ice sheet processes was very uncertain, and actually precluded setting a upper limit on what might be expected.

Could this water at one point quite suddenly finds it way out of the ice sheet into the ocean?

This ice sheet is losing mass at a rather larger rate (around 220 cubic kilometres per year) and it will take only another 1 - 2 oC world warming to raise the summer melt zone to the top of the Greenland ice pack after which point, in my understanding, the ice sheet will go into irreversible melt.

In this regard, I would observe that at least one important AGW effect, rising sea level, does not depend on a specific regional outcome so much as on global mean T. (At least, I think this is so (because my understanding is that most of the rise comes from lower density of warmer water, not from melting ice sheets — though again, not 100 % sure on this point)-RRB-.