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21

Antarctic sea ice extent for April 2014 reached 9.00 million square kilometers (3.47 million square miles), the largest ice extent on record by a significant margin. Is there any explanation for such an extreme excess of sea ice around Antarctica recently? I'll give four separate answers: It's not as significant an increase as you think. The ...


20

At least four things combined to prevent solid freeze-up during Ice/Slush Ball Earth periods: It takes a lower temperature to freeze water under pressure. Deep sea pressures are enormous. Ice floats. If it sank and new ice kept forming at surface, the seas might fill with ice. The surface freezes first and acts as an approx zero-degree C barrier, ...


14

What makes you think Geothermal energy and underwater volcanoes are too weak? The mid-oceanic ridge system alone is 50000 miles long. The mean heat flow at the surface (91.6 mW/m2) has to be accommodated somewhere. Also the freezing point of brine at a depth of 5000 m is approx -40 °C.


13

This question has already been answered on Skeptics.SE: Did the Arctic Ice Sheet grow by 60% from 2012 to 2013? The short answer is that those two graphs are consistent with each other. The first shows a 33 year trend of declining Arctic sea ice (summer minimum, I think), whereas the second highlights inter-annual variation in Arctic sea ice over the last ...


12

The Global warming potential (GWP) describes how much global warming a particular gas may induce in a particular time period. It is often expressed in terms of CO₂-equivalent. The best known greenhouse gases are carbon dioxide (CO₂), methane (CH₄), and water vapour (H₂O). Water vapour is short lived and therefore its emission is not a primary climate ...


9

Yool & Fasham in An Examination of the Continental shelf pump in an open ocean general circulation model Global Biogeochemical Cycles Volume 15, Issue 4, pages 831–844, divide the continental shelves into 32 named regions (see Fig. 2), and give areas for each (see table 1). The regions that are completely in the arctic ocean are: Russian arctic shelf ...


9

(Note: this is based on what I found in literature. Sea ice is not my expertise.) Short answer: We don't know. It may be related to changes in atmospheric temperature, wind stress, precipitation, ocean temperature, changes in coastal polynas, or other factors. The usual way to explain observed behaviour is through models. However, models are currently ...


9

Is an iceberg the size of Delaware [6,451 square kilometers] actually remarkable, or something that just happens from time-to-time? In March 2000 iceberg B-15 formed which was 11,000 sq. km. and 295 km long. In October 1998 iceberg A-38 formed which was 6,900 sq. km. A Delaware size iceberg would be the 3rd largest in the past 20 years. The 1990 ...


8

Developing since 2014, the crack was projected in 2015 to lead to "the largest calving event since the 1980s," according to this report in The Cryosphere journal by glaciologists studying the region. From 2010, "Overview of areal changes of the ice shelves on the Antarctic Peninsula over the past 50 years" says that the largest break-up event in that period ...


7

Not likely. Quoting Kelly Brunt, an ice scientist with NASA and at the University of Maryland, from What the Heck Is the Deal with This Weird, Square Iceberg? at LiveScience.com: What makes this one a bit unusual is that it looks almost like a square, which does not rhyme with anything in your suggested 1:4:9 ratio. The article mentions the obvious ...


7

I'm assuming this question is asking about the sea ice in the Arctic Ocean as opposed to ice caps such as that over Greenland. The sea ice on the Arctic Ocean is predominantly (overwhelmingly!) frozen ocean water. The Arctic Ocean loses 17 to 18 thousand cubic kilometers of ice every summer, only to regain most of that melted ice during the long Arctic ...


6

Do these "ozone-depleting substances" also have infrared-absorbing greenhouse impact unrelated to their ozone-depleting chemistry, or is the story more complex? Yes, the paper (I have access) actually said that the warming is because of the strong direct radiative forcing of the ozone-depleting agent rather than because of their ability to destroy ozone. ...


6

The IPCC said "Although the Hadley Centre climate model underestimates sea-ice extent and thickness, the trends of the two models are similar. Both models predict continued decreases in sea-ice thickness and extent (Vinnikov et al., 1999), so that by 2050, sea-ice extent is reduced to about 80% of area it covered at the mid-20th century." The graph on this ...


6

I found a natural-color image of the same area: 68.28 South, 60.47 East, North is up, resolution is 130m/px, which makes the whole image about 100 km x 100 km. Looking at the image i'd say that: sea ice is water with pieces of ice in it, the boundary between the two regions is clear water, probably caused by winds and currents moving the floating ice away ...


6

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, there seem to be more evidences available and therefore more relevant research on this event than the 2.1 BY one - and will consider in the following only the ...


5

Few things to notice are that while the Arctic Sea volume increased 50%, the volume increase was marginal compared with the volume of sea ice in 1979. Next, if you review the graph below, one year spikes are not that unusual, though if there was another 50% the volume increase from 2013 to 2014, it would be of note, given the rarity of significant year over ...


5

The National Snow and Ice Data Center website describes the process of ice formation on polar oceans. Virtually all of the young ice is made from ocean water which retains some brine in the process of forming. Older ice tends to lose the brine and have it replaced by air bubbles. Surface ice would form differently, either by frost, which tends to form in ...


5

There have been rectangular tabular icebergs in the past so this is not uncommon at all. Kelly Brunt, an ice scientist with NASA and the University of Maryland said: Tabular icebergs form, she said, through a process that's a bit like a fingernail growing too long and cracking off at the end. They're often rectangular and geometric as a result What ...


4

It depends on which pole. The south pole is in the middle of Antarctica, with mean temperatures of -57°C, liquid water doesn't exist there and the air is extremely dry. Therefore, I would say that it is not possible to create more ice due to the lack of liquid water. And if there were any liquid water it would freeze naturally. This will make sense if we ...


4

So I'm not asking about snow what is pressed into ice on the poles. Snowfall is obviously important for the ice that overlies Greenland and Antarctica; snowfall is the only source for ice on land. On the other hand, most of the ice in the Arctic Ocean and in the seas that surround Antarctica result from the freezing of seawater as opposed to snowfall. ...


3

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 Jormungand model. I tend to think it's sensible to assume that since photosynthetic bacteria survived, there must have been some open water. In fact, I have a recent ...


3

The water has an uncommon property: at 4°C it's heavier(most dense) that at 0°C. This makes ice floats on surface and ice is a good thermical isolator, preventing the water below freezing.


3

I looked at trends in Antarctic sea ice extent in the satellite era from 1979 to 2015 for both the summer minimum (February) and the winter maximum (September) and did not find a statistically significant trend. Please see: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2598152


2

In my survey of sea ice extent for the same period (1979-2015) I found that the apparent positive trend in dispersed sea ice in the Antarctic in September is anomalous and possibly spurious for two reasons: (1) there was no trend in concentrated sea ice extent or in the degree of sea ice dispersion, and (2) the residuals of the OLS trend line showed patterns ...


2

Concerning datasets, there are several, depends on Your final purpose. One of the simplest is output from OSI-SAF, which has info about Sea Ice edge, concentration, type, emissivity and drift. It is derived mostly from polar orbiting meteorological satellites, I guess. More detailed info can be found on Univ of Illinois pages Visual images from MODIS ...


1

I would recommend changing from ERA-Interim to ERA-5, since ERA-Interim will be outdated soon. This is the information currently given by the data provider: ERA Interim is being phased out. Users are strongly advised to migrate to ERA5. The last date to be made available in ERA Interim will be 31 August 2019, which will be released at the end of October ...


1

First lets take the question at face value and do the simple comparison. I will take the years 1979 and 2016 as arbitrary example, over a 37 year period - the longest for which accurate data are available. During that time the minimum extent of Arctic sea ice, defined as the area of Ocean with at least 15% of sea ice (as determined by satellite) decreased ...


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