35 votes
Accepted

Why is relative sea-level falling in Hudson Bay?

The area is experiencing post-glacial isostatic rebound. Much of Canada was covered in an extensive ice sheet in the last glacial period (the 'Ice Age'), from about 110 ka until 12 ka. The ice in the ...
  • 10.9k
15 votes
Accepted

Glaciology: odd pattern of smooth and ribbed chunks of ice in Antartica

What you see are ice bergs frozen into a sheet of sea ice. The "chunks" are the ice bergs. Ice shelves are fed by two sources, ice from the interior of the ice sheet and ice formed by compaction of ...
14 votes

Why is relative sea-level falling in Hudson Bay?

Because of post glacial rebound. The asthenosphere was pressed down under Laurentide ice sheet during last ice age and is now finding a new balance, without the weight of the ice. Note that around ...
  • 5,926
12 votes
Accepted

Will increased precipitation in Antarctica prevent sea level rise?

There is some scope for continuing debate because quantifying the various components of the ice/snow/water balance are fraught with difficulty, and many of the estimates have error bounds which ...
11 votes
Accepted

What geophysical knowledge have we learned by the construction of IceCube?

IceCube was initiated as the Antarctic Muon And Neutrino Detector Array (AMANDA) project. Since the sensor array involved drilling deep holes vertically into the Antarctic ice sheet by melting ice, no ...
9 votes
Accepted

Have russian drilling operations in lake Vostok succeeded yet?

The Russians did "succeed" to reach the water at borehole 5G-2 in 2012. However, the lake water flooded into the borehole due to overpressure, and refroze. They drilled again during the next campaign ...
9 votes
Accepted

Considering how old the Antarctic ice cover is, why isn't it much thicker?

Ice floats with gravity towards lower elevation, the flow continues until the base of the ice sheet becomes floating and the ice forms an ice shelf or icebergs. Due to the subglacial topography, ...
  • 5,926
8 votes
Accepted

Can ice caps reform if they disappear?

Yes, polar ice can melt -- significantly, if not completely, with substantial effects on human civilization. And it can stabilize and recover, but the question is at what pace relative to human ...
  • 3,160
7 votes

How much of the ice on earth is floating?

A first-order estimate is about 5%. This is a trickier question than it first appears because of ice shelves. Quoting from Kusky (2014): Ice shelves form where ice sheets move over ocean waters ...
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6 votes
Accepted

Did the surfaces of the oceans freeze over entirely during the snowball Earth periods?

By looking at the recent literature on the question, I see neither a consensus or a definitive answer on the extent of the snowball earth. Since the Neoproterozoic Snowball Earth event is more recent,...
  • 2,623
6 votes

At what rate are the polar ice caps shrinking?

It's important to identify which ice. Polar bears are arctic, and they hunt in large part on sea ice. Arctic sea ice is decreasing and the most common point used for the disappearing arctic ice is ...
  • 5,747
6 votes
Accepted

What is more important in Antarctica calving or basal melting of the ice shelves?

There are two studies published in 2013 that provide the most recent updates on this balance Depoorter, M.A. and 6 others, 2013. Calving fluxes and basal melt rates of Antarctic ice shelves. Nature, ...
6 votes
Accepted

How deep is the permafrost in the Antarctic?

According to "Permafrost, active-layer dynamics and periglacial environments of continental Antarctica" South African Journal of Science 98. pages 82-90: Only 25% of Antarctica has permafrost, as the ...
  • 5,912
6 votes
Accepted

How does ice-penetrating radar "see" through kilometers of ice without being absorbed?

Water molecules do interact with microwaves and in microwave ovens that operate at 900MHZ- 2.5GHz. This Radar instrument operates using Very High Freq Radio Waves at 193MHz [1]. At lower-than-...
5 votes

How does ice-penetrating radar "see" through kilometers of ice without being absorbed?

When electromagnetic waves travel through a medium, it can interact with the medium in question. But that interaction depends on the electric properties of the medium. Ice, being a dielectric medium, ...
5 votes

Last ice age: did glaciers move South or move downhill?

Did glaciers move South or move downhill? You are posing this as an either-or question. The answer is "Yes." The highest points above sea level in Manitoba, Minnesota, Ontario, Michigan, ...
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4 votes

Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather?

Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather? No, for a number of reasons. Ice sheets melt in the summer and rebuild in the winter. This is ...
  • 22.1k
4 votes

Considering how old the Antarctic ice cover is, why isn't it much thicker?

An interesting point to consider comes from your assumption of a constant rate of precipitation. Many earth system processes have non-trivial stochastic variations (or high-dimensional chaos). ...
  • 422
3 votes

Help understanding radar data in subglacial lake complex beneath Devon Ice Cap

In the figure: The top panel is the radar gram measured in depth below ice surface (m). It is flat because when you do the measurement it starts from the surface which is 0m. The distance from the ...
3 votes
Accepted

Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather?

The short answer is YES, but with a very important caveat. It won't be colder than usual, but colder than it would have been if the Greenland ice sheet weren't there to absorb that heat, and by a very ...
  • 17.2k
3 votes

Considering how old the Antarctic ice cover is, why isn't it much thicker?

There is a balance between precipitation on the one hand, and sublimation and outflow on the other. Ice evaporates directly to water vapor, especially during the summers. The thicker the ice, the ...
3 votes

Why is relative sea-level falling in Hudson Bay?

The graph shows sea level fall (SLF) at the Churchill tide gauge station. It is on the west side of Hudson Bay. These jagged edge ups and downs, and severe drop in a short time, indicate this is not ...
  • 31
3 votes

Will increased precipitation in Antarctica prevent sea level rise?

Drifting into what-if territory (and apologies for the lousy units) : Let's pick a rough rule of thumb that 30 inches of ( cold temperature) snow is equivalent to one inch of water. The land area ...
3 votes

Did the surfaces of the oceans freeze over entirely during the snowball Earth periods?

There is no consensus, but educated opinions. I tend to think that they did not freeze over. Some interesting arguments are given by Dorian Abbot in his paper where he first published about the ...
2 votes

Can ice caps reform if they disappear?

Ice caps are not essential for the planet to be habitable - over geological history, they are usually absent. Melting them would inconvenience many humans, though - there is a good calculator of this ...
2 votes

Can ice caps reform if they disappear?

Yes they can reform even if completely melted and they done this have in the geologic past, you just need to get the planet cool enough again. You only need two things for ice caps on earth, ...
  • 6,640
2 votes

Considering how old the Antarctic ice cover is, why isn't it much thicker?

According to "Ice Sheet Modeling" ice behaves as a deformable plastic material, which means that there is a critical shear stress, below which no strain (deformation or flow) will occur ... If ...
2 votes

Has Antarctica's coastline been completely mapped? (map discrepancies)

To complement the other answers: it is also true that the coastline in that region hasn't been fully documented yet, primarily because a large amount of it is covered by glaciers. As an example, Sif ...
  • 5,298
2 votes

Last ice age: did glaciers move South or move downhill?

Glaciers flow downhill and outwards. Outwards means if you form a glacier on flat (or with a round body, gravitationally equipotential) ground, then its weight will eventually push it outwards in all ...
  • 2,806

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