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Things to know about the A68 iceberg

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Re: Things to know about the A68 iceberg

#51

Post by voidmain »

kbutler wrote: post #21
voidmain wrote: post #12

So what would it cost to tow it somewhere with a need for fresh water?

Too much, even for smaller icebergs. Desalination is a cheaper option. https://www.theguardian.com/environment/2017/may/05/could-to...

> even for smaller icebergs

Naively, the energy cost of towing should go as the 2/3 power of the mass of the iceberg, whereas the energy cost of desalination is linear. So bigger is better!

Of course, it's a million times bigger than the biggest iceberg ever towed, so I guess there is some technical risk. But where's your can-do attitude?

Re: Things to know about the A68 iceberg

#52

Post by [deleted] »

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.

[deleted]

Re: Things to know about the A68 iceberg

#53

Post by kobeya »

strainer wrote: post #50
kobeya wrote: post #49

Earlier quoted context omitted.

TFA doesn't offer dimensions, but it does say the total area of the berg is 2,200 mi^2, which if square (overestimation given the picture) would give a depth of about 75km to this calving. The grandparent says that the ice shelf moves into the ocean at about 1km/yr. This specific calving has been going on in stages since at least the 1960's. Within the order of magnitudes of estimation, that lines up entirely with na…

I just see a hastily laid out argument. The 1km/yr we have no idea what it really means, does that relate to previous centuries? or is it just the rate observed during recent times? (while global warming has already been detected) The maps show the very location of these events, raised by several degrees C since 1950. The rate of this event is quite certainly strongly affected by local temperature, which is known to…

That's motivated reasoning. I'm not denying climate change. I'm just saying we should be very careful to not ascribe anything and everything to climate change unless there is clear evidence.

Re: Things to know about the A68 iceberg

#54

Post by stouset »

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…

Of course there's a link between this event and the climate. Clearly. If Antarctica weren't cold, there would be no ice shelf to begin with.

The salient point is that this specific event would have seemingly happened with or without our currently-changing climate. As the iceberg that the shelf extends from flows out toward the ocean, the shelf grows until it reaches a point where forces acting on the floating mass of ice induce part of it to calve away from the rest of the shelf.

Re: Things to know about the A68 iceberg

#55

Post by spullara »

idlewords wrote: post #28
spullara wrote: post #26

Earlier quoted context omitted.

It is the melting of the ice on above the water surface minus the difference in volume of the ice below the surface and the water it would become. Someone else mentioned that if the entire iceberg were melted it would cover California with 4.5in of water. If you divide that by the ratio of the ocean area to the area of California you get 0.13mm. I'm not sure how much is above the water vs below the surface but it see…

Just enough of it is above the surface to account for the change of volume when it melts. Or equivalently, it displaces its own weight in water.

Hmm. I see what you are saying. So they probably did do the calculation I referenced but I agree it is probably faulty. However, there is some rise from melting: https://www.newscientist.com/article/dn18841-melting-iceberg...

Re: Things to know about the A68 iceberg

#57

Post by phkahler »

ericd wrote: post #17
phkahler wrote: post #14

Earlier quoted context omitted.

The thing is... If we wanted to not in interfere, and let the natural process do its thing, we'd be looking at the end of the inter-glacial period in the next 1000 years. After that we'd see glaciation starting to cover a lot of the northern hemisphere. Sea levels would start to drop - ultimately several hundred feet, exposing the continental shelf everywhere. All our coastal cities would be inland. Some have said th…

Nobody pretends the planet was in steady state before humans ramped up CO2 production, everyone knows about the last ice age.

Yes, they do pretend. Sea levels have been rising for 10000 years and they act like that trend stopped and the rise from here on out is all caused by human activity.

Re: Things to know about the A68 iceberg

#58

Post by ericd »

phkahler wrote: post #57
ericd wrote: post #17

Earlier quoted context omitted.

Nobody pretends the planet was in steady state before humans ramped up CO2 production, everyone knows about the last ice age.

Yes, they do pretend. Sea levels have been rising for 10000 years and they act like that trend stopped and the rise from here on out is all caused by human activity.

No, they're saying that we've caused it to accelerate massively. 10k years is probably long enough for us to adapt, 50 is probably not.
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