This feedback could potentially result in the rapid loss
of parts of the ice sheet, as grounding lines retreat along troughs and basins that deepen towards the ice sheet's interior.
My Columbia University colleague Dr. James Hansen, for 30 years NASA's leading climate scientist, warns us that even with warming well below 2 - degree C, human - induced warming could lead to the disintegration
of parts of the ice sheets of Antarctica and Greenland, causing the sea level to rise by as much as 6 - 9 meters.
Not exact matches
Peter Neff, a glaciologist at the University
of Rochester who travels regularly to the Antarctic, said ground observations would never tell you the full story
of what's going on with
ice sheets in that
part of the world.
Using an
ice cream scoop, place mounds
of the cookie dough 1/2 inch a
part on the baking
sheet.
1) Mix flour, butter and
icing sugar in a bowl using two knives to cut the butter until the mixture resembles fine breadcrumbs 2) Add in the egg yolks and vanilla extracts and mix well, then add
iced water until the dough starts to come together 3) Shape the dough into a ball on a cool, flat, floured surface 4) Flatten dough into a disc and then wrap in plastic wrap, and chill in the refrigerator for at least 30 minutes 5) Meanwhile, peel, core and slice the apples into as thin slices as possible 6) Mix sugar and ground cinnamon powder with sliced apples and let it rest for a while 7) Pre-heat oven to 180 deg cel 8) Once dough has chilled, roll pastry dough on a
sheet of parchment paper until it has expanded to the size
of the tart mold (I used a rough mold the size
of a large pizza) 9) Leaving at least an inch
of dough free, arrange apple slices by overlapping them slightly in the shape
of a circle, starting from the outermost
part of the circle, until you reach the inside 10) Fold the edges
of dough over the filling and then sprinkle the dough with a bit
of sugar 11) Bake for about 40 - 45 minutes, or until the crust is golden brown and the apples are soft 12) Serve warm, with a side
of whipped cream or
ice cream (optional)
But, rapid change in the behavior
of parts of the Antarctic
ice sheet might cause much greater rise than is often included in coastal planning.
The Earth's climate system is characterised by complex interactions between the atmosphere, oceans,
ice sheets, landmasses and the biosphere (
parts of the world with plant and animal life).
Any
parts of the bed this low are easily exposed to ocean water, allowing the
ice sheet to weaken from below as the ocean water warms.
Parts of the massive
ice sheet once considered stable have been shown to be melting in new research
But now Jonathan Bamber at Bristol University, UK, has analysed which
parts of the West Antarctic
ice sheet are vulnerable.
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.
They found that western Antarctica has recently seen warmer, saltier water being driven under the shelf — the
part of the
ice sheet that sticks out over the ocean (Science, doi.org/xkx).
Lacking many
ice shelves to stem its flow, the glacier is particularly vulnerable to warming, part of the so - called weak underbelly of the West Antarctic Ice She
ice shelves to stem its flow, the glacier is particularly vulnerable to warming,
part of the so - called weak underbelly
of the West Antarctic
Ice She
Ice Sheet.
This effect is particularly apparent in
parts of the West Antarctic
Ice Sheet (WAIS), long regarded as the more vulnerable
part of the continent to climate change.
Paolo agrees that the new measurements are only
part of the ongoing story about the future
of Antarctica's
ice sheet.
In effect, this UAV survey across the ablation zone
of the
ice sheet perfectly bridges the gap between people on the ground studying what's under their feet in just one
part of the
ice sheet, and the satellite data that shows what's going on across the entire
ice sheet.
Thousands
of marks on the Antarctic seafloor, caused by icebergs which broke free from glaciers more than ten thousand years ago, show how
part of the Antarctic
Ice Sheet retreated rapidly at the end of the last ice age as it balanced precariously on sloping ground and became unstab
Ice Sheet retreated rapidly at the end
of the last
ice age as it balanced precariously on sloping ground and became unstab
ice age as it balanced precariously on sloping ground and became unstable.
Even if the central
parts of the
ice sheet can survive a warming climate, melting is likely at the extremities, says Sugden.
«IceBridge surveyed previously unexplored
parts of the Greenland
Ice Sheet and did it using state -
of - the - art CReSIS radars,» said study co-author Mark Fahnestock, an IceBridge science team member and glaciologist from the Geophysical Institute at the University
of Alaska Fairbanks (UAF - GI).
the south - bound expedition had cleared that vast plain
of floating
ice which flows down from the great mountains
of the interior and covers the southern
part of Ross Sea throughout an area above 20,000 square miles with an
ice sheet approximately 800 feet in thickness, and had begun to climb the heights which form the mountainous embayment at the head
of Ross Sea.
The work will continue for two more summers, exploring different
parts of the
ice sheet.
In
parts, it's nearly three miles thick, and, with the nearby West Antarctic
Ice Sheet, it blankets an expanse roughly the size
of the United States and Mexico combined.
When
parts of the
ice melt, liquid water trickles to the base and this can lubricate the underside
of the
ice sheet, allowing it to slide more quickly into the sea and drive up sea levels at a faster rate.
So
parts of these
ice sheets, but not all, must have melted during the long - ago warm period.
«There's a growing push to understand the impact
of microorganisms on glaciers and
ice sheets,» says Christopher Williamson, a microbiologist at the University
of Bristol in England who wasn't
part of the study.
Williamson is
part of a five - year project investigating the impact
of ice algae, which is different than snow algae, and bacteria on the Greenland
ice sheet (SN: 5/20/00, p. 328).
Part of the fresh water likely originates from melting
of the Greenland
Ice Sheet north
of the Young Sound and is transported with the East Greenland ocean current along the eastern coast
of Greenland.
Ice sheets aren't the static scabs
of frost that scientists once imagined, but rather complex structures with many moving
parts.
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 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.
This is the case with land - based
ice sheets in the Arctic, Greenland and
parts of Antarctica.
The sediment cores used in this study cover a period when the planet went through many climate cycles driven by variations in Earth's orbit, from extreme glacial periods such as the Last Glacial Maximum about 20,000 years ago, when massive
ice sheets covered the northern
parts of Europe and North America, to relatively warm interglacial periods with climates more like today's.
Hawkings and his collaborators spent three months in 2012 and 2013 gathering water samples and measuring the flow
of water from the 600 - square - kilometer (230 - square - mile) Leverett Glacier and the smaller, 36 - square - kilometer (14 - square - mile) Kiattuut Sermiat Glacier in Greenland as
part of a Natural Environment Research Council - funded project to understand how much phosphorus, in various forms, was escaping from the
ice sheet over time and draining into the sea.
When large
parts of the
ice sheet melted at the end
of the
ice age, the weight
of the
ice sheet decreased, and the crust began to rebound.
Parts of the
ice sheet considered at risk hold enough
ice to raise the global sea level by 22 feet.
The international research initiative IceGeoHeat led by the GFZ German Research Centre for Geosciences establishes in the current online issue
of Nature Geoscience that this effect can not be neglected when modeling the
ice sheet as
part of a climate study.
Such lakes
of water pool at the bottom
of an
ice sheet or glacier, and were known to be scattered under
parts of Antarctica.
Water that collects in valleys underneath the
ice sheet, in the Gamburtsev Mountains, refreezes when it passes under thinner
parts of the
ice sheet that are less insulated from cool surface temperatures.
The oldest
ice, trapped in the deepest
part of the
ice sheet, could reveal temperatures eons ago.
«We had little information in the south, but we had three or four more cores in the northern
part of the
ice sheet.
Based on the southern core we thought this was a localized low heat - flux region — but our model shows that a much larger
part of the southern
ice sheet has low heat flux.
«The beds at the margins
of the
ice sheet... are probably one
of the least explored
parts of Earth's surface,» said Ian Howat, a glaciologist at Ohio State University who did not participate in the research.
Radar measurements
of the height
of the
ice over
parts of the continent suggest that the huge East Antarctic
ice sheet grew slightly between 1992 and 2003.
«During the last
ice age around 20,000 years ago, large
parts of Canada were covered by an
ice sheet.
The academics suggest that the melting
of the
ice sheet may have been caused in
part by the fact that some
of it rests in basins below sea level.
«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.&raq
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.&r
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.&raq
ice sheet is new and very surprising.&r
sheet is new and very surprising.»
But the large volumes
of data on Arctic sea and land
ice that IceBridge has collected during its nine years of operations there have also enabled scientific discoveries ranging from the first map showing what parts of the bottom of the massive Greenland Ice Sheet are thawed to improvements in snowfall accumulation models for all of Greenla
ice that IceBridge has collected during its nine years
of operations there have also enabled scientific discoveries ranging from the first map showing what
parts of the bottom
of the massive Greenland
Ice Sheet are thawed to improvements in snowfall accumulation models for all of Greenla
Ice Sheet are thawed to improvements in snowfall accumulation models for all
of Greenland.
Like frozen levees, the retreating glaciers pin back more stable
parts of the Greenland - size
ice sheet.
The Cordilleran
Ice Sheet covered large parts of North America during the Pleistocene - or last ice age - and was similar in mass to the Greenland Ice She
Ice Sheet covered large
parts of North America during the Pleistocene - or last
ice age - and was similar in mass to the Greenland Ice She
ice age - and was similar in mass to the Greenland
Ice She
Ice Sheet.
Glaciers are found in mountain valleys and also form
parts of ice sheets.