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Things to know about the A68 iceberg

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Re: Things to know about the A68 iceberg

#31

Post by rm999 »

DrScump wrote: post #24
dukoid wrote: post #2

TLDR: The calving of the 1.1 trillon ton ice berg (2x amount of water used in the US each year) marks the end of a decades long splintering, first seen by satellites in the 1960s. 1. What's next? It will drift north along the coast of the Antarctic Peninsula, then northeast into the south Atlantic Ocean. Likely no threat to ships navigating the area. Can take months to splinter apart. 2. Is this climate change? Calvi…

Will it make the oceans rise? barely (0.1 mm) Where do they get that? The melting of already-floating icebergs has zero net effect on sea lever or (liquid) water volume. It would take a huge amount of added water to make even a .1mm effect worldwide .

Could be thermostatic sea level rise: the water will spread to warmer parts of the ocean and expand.

Re: Things to know about the A68 iceberg

#32

Post by idlewords »

strainer wrote: post #8
idlewords wrote: post #7

Earlier quoted context omitted.

We don't have long enough experience with ice shelves to know what their baseline behavior is. And the effects of global warming in the Antarctic are less straightforward than in the Arctic. For example, winter sea ice extent there is increasing, not decreasing.

As I understand it - the sea ice extent is a quite different matter being thin and regenerating yearly. These lost iceshelves (including Larsen B in 2001) were hundreds of meters thick. I wonder what age these shelves were and what a sustainable rate of such events would be. Without seeing such information I dont trust general statements on the events meaning. As another massive iceshelf breaks off - it really looks…

I cited sea ice as an example of counterintuitive effects of climate change.

These shelves move fairly rapidly, and will calve with or without global warming. The Ross Ice Shelf, for example, moves northwards at about 1 km/year.

Re: Things to know about the A68 iceberg

#33

Post by [deleted] »

strainer wrote: post #8
idlewords wrote: post #7

Earlier quoted context omitted.

We don't have long enough experience with ice shelves to know what their baseline behavior is. And the effects of global warming in the Antarctic are less straightforward than in the Arctic. For example, winter sea ice extent there is increasing, not decreasing.

As I understand it - the sea ice extent is a quite different matter being thin and regenerating yearly. These lost iceshelves (including Larsen B in 2001) were hundreds of meters thick. I wonder what age these shelves were and what a sustainable rate of such events would be. Without seeing such information I dont trust general statements on the events meaning. As another massive iceshelf breaks off - it really looks…

[deleted]

Re: Things to know about the A68 iceberg

#34

Post by elif »

Good news about the bedrock holding the iceberg in place.

As a casual earth science enthusiast, I believe this means that the melt-water will stay proximal, and will encourage accelerated freezing on the coast, somewhat "repairing" the damage.

When it breaks up/drifts away, the coast will be subject to normal freezing patterns from the briny water.

Re: Things to know about the A68 iceberg

#35

Post by eps »

DrScump wrote: post #24
dukoid wrote: post #2

TLDR: The calving of the 1.1 trillon ton ice berg (2x amount of water used in the US each year) marks the end of a decades long splintering, first seen by satellites in the 1960s. 1. What's next? It will drift north along the coast of the Antarctic Peninsula, then northeast into the south Atlantic Ocean. Likely no threat to ships navigating the area. Can take months to splinter apart. 2. Is this climate change? Calvi…

Will it make the oceans rise? barely (0.1 mm) Where do they get that? The melting of already-floating icebergs has zero net effect on sea lever or (liquid) water volume. It would take a huge amount of added water to make even a .1mm effect worldwide .

Melting of an ice cube in a glass of water doesn't change the water level. It was in the highschool physics cirriculum where I'm from.

This won't hold true when melting a _freshwater_ ice in _salty_ water, but I too doubt the change will be anywhere near 0.1mm

Re: Things to know about the A68 iceberg

#37

Post by Baeocystin »

rm999 wrote: post #31
DrScump wrote: post #24

Earlier quoted context omitted.

Will it make the oceans rise? barely (0.1 mm) Where do they get that? The melting of already-floating icebergs has zero net effect on sea lever or (liquid) water volume. It would take a huge amount of added water to make even a .1mm effect worldwide .

Could be thermostatic sea level rise: the water will spread to warmer parts of the ocean and expand.

Thermal expansion is the primary source of sea level rise in general, isn't it?

Re: Things to know about the A68 iceberg

#38

Post by mbrookes »

elif wrote: post #34

Good news about the bedrock holding the iceberg in place. As a casual earth science enthusiast, I believe this means that the melt-water will stay proximal, and will encourage accelerated freezing on the coast, somewhat "repairing" the damage. When it breaks up/drifts away, the coast will be subject to normal freezing patterns from the briny water.

I think you may have misunderstood - it is the Larsen C shelf that is held in place, not the iceberg that it calved:

An iceberg the size of Delaware is now in motion. If it follows the path of previous icebergs from the Larsen Ice Shelf, it will drift north along the coast of the Antarctic Peninsula before heading northeast into the south Atlantic Ocean, according to NASA.

Re: Things to know about the A68 iceberg

#39

Post by noiv »

nonbel wrote: post #9
dukoid wrote: post #2

TLDR: The calving of the 1.1 trillon ton ice berg (2x amount of water used in the US each year) marks the end of a decades long splintering, first seen by satellites in the 1960s. 1. What's next? It will drift north along the coast of the Antarctic Peninsula, then northeast into the south Atlantic Ocean. Likely no threat to ships navigating the area. Can take months to splinter apart. 2. Is this climate change? Calvi…

>"2. Is this climate change? Calving is a natural process and Antarctica is not breaking apart, but climate change can't be ruled out." "Climate change" doesn't make specific enough predictions about this type of stuff to ever be ruled out, people could just keep coming up with ideas about X indefinitely: Climate Change -> X -> Larsen C rift A more accurate way to put it is that, up until now, all proposed ideas for…

> "Climate change" doesn't make specific enough predictions about this type...

Actually it does. In a warming world more frequent calving events are expectable. This part of Antarctica shows quite some positive temperature anomalies. So, asking whether Larsen C would be still intact today without Climate Change the answer is certainly yes.

Re: Things to know about the A68 iceberg

#40

Post by nonbel »

noiv wrote: post #39
nonbel wrote: post #9

Earlier quoted context omitted.

>"2. Is this climate change? Calving is a natural process and Antarctica is not breaking apart, but climate change can't be ruled out." "Climate change" doesn't make specific enough predictions about this type of stuff to ever be ruled out, people could just keep coming up with ideas about X indefinitely: Climate Change -> X -> Larsen C rift A more accurate way to put it is that, up until now, all proposed ideas for…

> "Climate change" doesn't make specific enough predictions about this type... Actually it does. In a warming world more frequent calving events are expectable. This part of Antarctica shows quite some positive temperature anomalies. So, asking whether Larsen C would be still intact today without Climate Change the answer is certainly yes.

As I said a month ago when this coverage started, it is very strange how there are so many people (in the media and internet posters) who are so sure about that, when the actual people studying it claim otherwise: https://news.ycombinator.com/item?id=14577296

>“Although this is a natural event, and we’re not aware of any link to human-induced climate change, this puts the ice shelf in a very vulnerable position. This is the furthest back that the ice front has been in recorded history. We’re going to be watching very carefully for signs that the rest of the shelf is becoming unstable.” http://www.projectmidas.org/blog/calving/

>'Andrew Shepherd, professor of Earth Observation at the University of Leeds, agreed. “Everyone loves a good iceberg, and this one is a corker,” he said. “But despite keeping us waiting for so long, I’m pretty sure that Antarctica won’t be shedding a tear when it’s gone because the continent loses plenty of its ice this way each year, and so it’s really just business as usual!”https://www.theguardian.com/world/2017/jul/12/giant-antarcti...

>"And while climate change is accepted to have played a role in the wholesale disintegration of the Larsen A and Larsen B ice shelves, Luckman emphasised that there is no evidence that the calving of the giant iceberg is linked to such processes." https://www.theguardian.com/world/2017/jul/12/giant-antarcti...

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