Antarctic Sea Ice Hits Lowest Winter Maximum On Record (phys.org) 55
An anonymous reader quotes a report from Phys.Org: The sea ice around Antarctica likely had a record low surface area when it was at its maximum size this winter, a preliminary US analysis of satellite data showed Monday. As the southern hemisphere transitions into spring, the US National Snow and Ice Data Center (NSIDC) said in a statement that Antarctic sea ice had only reached a maximum size of 16.96 million square kilometers (6.55 million square miles) this year, on September 10. The ice pack typically reaches its largest size during the colder winter months, so the September 10 reading will likely remain this year's maximum.
"This is the lowest sea ice maximum in the 1979 to 2023 sea ice record by a wide margin," said the NSIDC, a government-supported program at the University of Colorado at Boulder. At its high-point this year, the sea ice was 1.03 million square kilometers smaller than the previous record, roughly the size of Texas and California combined. "It's a record-smashing sea ice low in the Antarctic," said NSIDC scientist Walt Meier. He added that the growth in sea ice appeared "low around nearly the whole continent as opposed to any one region."
"This is the lowest sea ice maximum in the 1979 to 2023 sea ice record by a wide margin," said the NSIDC, a government-supported program at the University of Colorado at Boulder. At its high-point this year, the sea ice was 1.03 million square kilometers smaller than the previous record, roughly the size of Texas and California combined. "It's a record-smashing sea ice low in the Antarctic," said NSIDC scientist Walt Meier. He added that the growth in sea ice appeared "low around nearly the whole continent as opposed to any one region."
What about the volume? (Score:3)
That's likely a more significant metric than the area alone
Surface area is supposedly energy reflective (Score:4, Informative)
The supposed concern is that losing the white/snowy surface area results in greater heat absorption.
Hence the preference to worry about surface area vs total volume.
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Re: Surface area is supposedly energy reflective (Score:2)
You could easily look up the albedos of ocean and sea ice.
Re:Surface area is supposedly energy reflective (Score:4, Interesting)
The supposed concern is that losing the white/snowy surface area results in greater heat absorption.
Exactly. Less ice means more sunlight absorption which means a warmer ocean, which means even less ice. There is a strong feedback effect.
This feedback effect is already happening in the Arctic but was delayed around Antarctica because warmer temperatures meant more moisture in the air, heavier snowfall onto the ice, making it last longer. But the Antarctic has now warmed enough that the extra snow is no longer enough to keep the ice pack from shrinking.
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I sometimes wonder if the snowy/white landscape theory has any real merit.
Sure, lighter colors are more reflective, but does that matter much outside of localized measurements?
Earth has atmosphere, and overall higher temps mean more water in the air, which means more energy absorption occurs at much higher altitudes, where dissipation already naturally occurs.
Is there any actually solid science on this? Stuff that goes really deep into the knock on effects?
Re:Surface area is supposedly energy reflective (Score:4, Informative)
Light reflected from snow is in the visible range, so water vapor is transparent.
Water vapor will absorb infrared, such as the sun heating dark ground, which then emits IR, but that's not what snow does.
Also, the air over Antarctica is very dry. So there isn't much water vapor there.
Re:Surface area is supposedly energy reflective (Score:5, Interesting)
It's pretty straightforward. Earth sensing satellites regularly measure the albedo of the ground they're passing over, it's one of the ways they measure ice coverage. Higher albedo means more light being reflected, which means less heat being absorbed, and yes it's responsible for global rather than local effects because it's such a massive area covered. Eighty percent of the light was being reflected, instead of about 15% for land and 10% for seawater.
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I still have a hard time understanding how deep ocean water at the poles absorbs much energy from sunlight. Shallow water sure; you get a thermocline and you heat the bottom; even if half the solar energy is reflected off the water it wil still have an impact.
Deep water though I get how the reds are going to be absorbed at the top layers, but there doesn't intuatively seem to be much absorbed energy at deeper levels.
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However as a general part of the ocean's behavior of moving heat from the relative source (the tropics) to the relative sink (poles), surface currents flow pole
Re: Surface area is supposedly energy reflective (Score:2)
Sunlight penetrates water. That's how. The energy is absorbed by the sea, instead of being reflected by ice.
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Intuitively: The bigger (and colder) the heat sink, the more heat it will absorb.
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Not really. Sea ice doesn't affect sea level one way or the other, so really this is a just a crude but convenient measure of regional temperature.
Of course, when coastally located ice shelves (which are year round) start collapsing, that *does* have an indirect effect on sea level because of their interaction with coastal glaciers.
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Indirectly, it does.
Right, but not the ice we're talking about here.
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No we're talking maximum winter sea ice *extent*. Ice shelves are (were) permanent features.
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That's likely a more significant metric than the area alone
In what way? Do you think that the reduction in surface area is somehow compensated for by magical extra coldness that makes the sea-ice thicker in the middle?
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That's likely a more significant metric than the area alone
In what way? Do you think that the reduction in surface area is somehow compensated for by magical extra coldness that makes the sea-ice thicker in the middle?
As I understand it, sea ice coverage of as low as 15% is counted as ice-covered.
So a thin sheet of ice covering 30% of a given area is no different than a 100% coverage, 1 meter thick?
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And when you put an ice cube in a glass of water does it magically grow thicker in the middle as it melts around the edges? That's my point. There's no mechanism that affects an area the size of the arctic circle which can cause it to melt around *all* edges while adding ice thickness in the middle.
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And when you put an ice cube in a glass of water does it magically grow thicker in the middle as it melts around the edges? That's my point. There's no mechanism that affects an area the size of the arctic circle which can cause it to melt around *all* edges while adding ice thickness in the middle.
Sunlight, cloud cover, air circulation above, currents flowing below. Those effects are not uniform
Re: What about the volume? (Score:1)
Hmm.. How about the number of viable emperor penguin colonies left? That seems like an important metric.... well, at least to the penguins...
https://edition.cnn.com/2023/0... [cnn.com]
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Nature,
Mass balance of the Antarctic Ice Sheet from 1992 to 2017
"The Antarctic Ice Sheet is an important indicator of climate change and driver of sea-level rise. Here we combine satellite observations of its changing volume, flow and gravitational attraction with modelling of its surface mass balance to show that it lost 2,720â±â1,390 billion tonnes of ice between 1992 and 2017, which corresponds to an increase in mean sea level of 7.6â±â3.9 millimetres (errors are
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Grrr. I hate that you can't simply cut and paste into Slashdot.
"The Antarctic Ice Sheet is an important indicator of climate change and driver of sea-level rise. Here we combine satellite observations of its changing volume, flow and gravitational attraction with modelling of its surface mass balance to show that it lost 2,720 +/- 1,390 billion tonnes of ice between 1992 and 2017, which corresponds to an increase in mean sea level of 7.6 +/- 3.9 millimetres (errors are one standard deviation). Over this p
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I don't disagree. However, given the ice-forming dynamics, it's highly unlikely that you could significantly reduce areal coverage without also having a decrease in volume. Ice forming on the sea isn't likely to form chunks with less horizontal area, but the same or more volume. Or maybe the ice chunks form to the same size as before, but there are fewer of them: you still get a commensurate reduction in volume.
In all likelihood, the %reduct
Why would sea ice max in winter? (Score:2)
Re:Why would sea ice max in winter? (Score:4, Interesting)
The ice around Antarctica is almost completely frozen sea water, not much of it is glacial ice. It freezes in winter, which causes the ice pack to expand.
The percentage of glacial ice is expanding, warmer oceans mean more humidity, so more snow falling on the glaciers, warmer air means melting glacial ice which lubricates the base of the glaciers, so they advance faster into the ocean. Glacial ice will go from (working from memory) 2% to 3% of the Antarctic ice pack over the next decade or two.
Lowest _so_ _far_. (Score:1, Informative)
Nobody should be surprised about this. The trend of global warming is going to continue to gain momentum until we finally get this way overdue eco-turnaround happening. ... Then it might come to some halt/new equilibrium a few decades later, barring epic cascade effects of which there are plenty enough to be type-A "end of civilization" nightmare material.
Most glaciers have their days numbered, as likely does the Colorado River water system, the German Forrest, Russian permafrost and - qed - the polar ice c
Time to claim some land (Score:2)
Re: Time to claim some land (Score:2)
I think you'll find it's already dividied up... last time I heard China was trying to get in on the game, as they were late to the party.
Re: Time to claim some land (Score:1)
Removing ice from the land doesn't make it cropland.
Making weather warmer on average doesn't mean it won't have extreme events which wipe out crops.
womp womp (Score:2)
There's some of that maliciously bad moderation I was talking about. Modding down facts is a shit look.
1966 stamps its foot (Score:5, Interesting)
Analysis of the NIMBUS satellite data indicates that the coverage was highly variable in the 1960s, and 1966 set a low of 16 million sq km
https://www.earthdata.nasa.gov... [nasa.gov]
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and 1966 set a low of 16 million sq km
Just curious, where did you get this specific data point? Couldn't find it in the link you provided.
Re:1966 stamps its foot (Score:5, Interesting)
Analysis of the NIMBUS satellite data indicates that the coverage was highly variable in the 1960s, and 1966 set a low of 16 million sq km
Just curious, where did you get this specific data point? Couldn't find it in the link you provided.
The article he linked to included the paragraph "“We were shocked by what we discovered in these images,” says Gallaher. “We thought, OK, all reports from the 1960s were that it was colder, so we expected to see a lot more sea ice. In fact, 1964 was the largest sea ice extent until 2014. Then in 1966 we saw the lowest ice extent that was ever seen. This was totally unexpected. There’s a lot more variability in sea ice extent than we ever could have imagined.”"
As to where the specific figure of 16 million square km came from, I'm afraid I'm at a loss. While the data is searchable (at NSIDC [nsidc.org]) it's not particularly 'amateur' user friendly, and I've got others things I should be doing... :-/
I do think that it's worth pointing out that this summary [nsidc.org] of the project's findings, includes these lines: "With those images, Campbell produced the first satellite maps of the sea ice edge in 1964 and an estimate of September sea ice extent for both the Arctic and the Antarctic. According to the data, September Antarctic sea ice extent measured about 19.7 million square kilometers. “That’s higher than any year observed from 1972 to 2012,” Meier said."
Yearly variability is to be expected. Take a look at this image [nsidc.org] showing Arctic sea ice levels. If we looked at only 1996 one could say "look, sea ice hasn't declined at all since records began"; if instead we only looked at the period 2010-2012 one could say "at this rate there'll be no sea ice left in 5 years time". Obviously both extremes are ludicrous.
The long term trend, however, is blatantly obvious.
Re:1966 stamps its foot (Score:4, Insightful)
Online "data" can be "adjusted" to reflect "new corrections" to old measurements. It's best to look at actual hardcopy published at the time. ...Until that is all burned in favor of online, that is.
low sea ice = low krill production. (Score:2)
The Last Continent (Score:2)
Can we get more nuclear fission power now? (Score:5, Insightful)
There's been IPCC reports on how we won't meet any CO2 emissions reduction goals without more nuclear fission power plants. If melting polar ice from global warming concerns you then "follow the science" and advocate for nuclear power.
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I discovered that it is not productive to argue why the polar ice is melting since those that convinced themselves that global warming is an existential threat to human civilization are not likely to change their minds any time soon. What I believe to be more productive is to debate solutions, because we can agree on the solution even if we disagree on the problem. Because nuclear fission is an energy source with low CO2 emissions (lower than any form of solar power) and a high EROEI we are going to need
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I don't disagree that nuclear is a lower CO2 option than fossil fuels.
HOWEVER
In none of the pro nuclear postings that regularly appear here does anyone discuss the whole picture.
How is waste handled? -- or is this one of those externalities that everyone conveniently ignores?
Waste from spent fuel rods is highly toxic, highly reactive chemically and will take a long time to decay. Who has a plan for it? Store it in a geologically active area, near the coast (remember sea level rises) like the UK does? Put
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So, what about the nuclear waste?
Kyel Hill video: https://www.youtube.com/watch?... [youtube.com]
Decouple Media: https://www.youtube.com/watch?... [youtube.com]
Another from Decouple Media: https://www.youtube.com/watch?... [youtube.com]
Sabine Hossenfelder: https://www.youtube.com/watch?... [youtube.com]
There's plenty more where that came from. I only took me a few minutes to find those videos. Each video has cited primary sources, and with some searches on the primary sources there should be plenty of other related sources that are found.
The accusation of me c
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There's been IPCC reports on how we won't meet any CO2 emissions reduction goals without more nuclear fission power plants
Link to it.
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Link to it.
Type in something like "IPCC nuclear energy" into any web search and you'll get something like this:
https://nei.org/news/2022/ipcc... [nei.org]
If that's not good enough then I suggest running your own search. If what you find is something you believe is erroneous or not accurately represented by my claim then provide some links of your own.
As a bit of a bonus:
UK plans: https://www.bbc.com/news/busin... [bbc.com]
UAE: https://www.bbc.com/news/world... [bbc.com]
Those Glaciers look a bit weedy (Score:4, Interesting)
I spent yesterday in the company of a couple of arctic glaciers.
In contrast to their normal behavior, they did not reach the ocean. The front face was some distance from the shore.
The sea ice was coming in so we had to leave (the dingys wouldn't be able to ride us back to the ship over mini icebergs) but that sea ice was due to the temp. None of it was coming from the glaciers. That we got to visit at all, this late in the season is due to the higher than normal temperatures.
Heading South now. Next up, Jan Mayen the sea lets us reach land.