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The Netherlands will be fine

The Netherlands will be fine

Posted Jul 26, 2024 22:04 UTC (Fri) by paulj (subscriber, #341)
In reply to: The Netherlands will be fine by Wol
Parent article: Imitation, not artificial, intelligence

Potential sea level rise from ice melt is fairly limited, less than a metre I thought. There's a lot of ice, but there's way, _way_ more sea.

The predictions of many metres of sea level rise are based on thermal expansion of the oceans. Which won't happen suddenly, but slowly (OTOH, trying to reverse such warming would be equally slow).


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The Netherlands will be fine

Posted Jul 26, 2024 22:30 UTC (Fri) by Wol (subscriber, #4433) [Link]

> Potential sea level rise from ice melt is fairly limited, less than a metre I thought.

Which is why I've been saying a metre ... the danger lies in the fact that that metre rise is expected to take a century. We were shocked at how fast the Arctic melted ... and Antartica doesn't even need to melt - all it needs is to slide into the sea, and the rate of flow will only increase. Let's hope it doesn't accelerate faster than expected ... Greenland is a poster child here - the glaciers are flowing much faster now the ice shelf has gone ...

Cheers,
Wol

The Netherlands will be fine

Posted Jul 26, 2024 23:12 UTC (Fri) by malmedal (subscriber, #56172) [Link] (1 responses)

My understanding is that sea-level rise if all ice melts is about 70 meters, and that the models say we have already emitted enough CO2 to get 3 to 10 meters. That will take hundreds of years however, so there is time to mitigate.

The scariest realistic scenario is Thwaite's glacier, which, when it collapses, can give us 65 cm all by itself in the span of maybe ten years. Those ten years could start tomorrow or in a hundred years.

The conservative IPCC estimate is only about 60 cm by 2100, but even that will be problematic.

Consider; the daily tidal forces on the ocean only amounts to about 50cm due to the moon and 25cm from the sun, so in theory a max of 75cm when they are in sync.

However the actually observed tides can be more than ten meters the Bay of Fundy and almost nothing in the Caribbean due to variations in geography.

Similarly even if we only get 60cm it will be unevenly spread, some locations will get a lot, some nothing, some may even see a decrease.

I don't think we have models good enough to confidently predict who will win and loose. If I were to guess, I'd say the biggest victim would be Bangladesh.

The Netherlands will be fine

Posted Jul 27, 2024 20:26 UTC (Sat) by Wol (subscriber, #4433) [Link]

> The conservative IPCC estimate is only about 60 cm by 2100, but even that will be problematic.

And I seriously expect (a) that estimate is wrong, and (b) it'll be wrong as in too low.

As I said, we consistently underestimate change. Go back to 1980, rampant population growth, the EXTREMELY OPTIMISTIC forecasts of Y2K population said 8Bn. We undershot by over 2Bn I think. (The "we think it'll actually be this" estimate was 12Bn!)

Thwaites glacier, 10 years? Let me guess it'll actually be five. Quite likely less.

Cheers,
Wol

The Netherlands will be fine

Posted Jul 28, 2024 10:05 UTC (Sun) by Wol (subscriber, #4433) [Link]

> The predictions of many metres of sea level rise are based on thermal expansion of the oceans. Which won't happen suddenly, but slowly (OTOH, trying to reverse such warming would be equally slow).

Sorry, wrong physics again. Warming the oceans will use (very slow) conduction. However, both the troposphere and the oceans have very efficient cooling mechanisms. For every century it takes to rise, it'll take maybe a decade to cool?

As soon as we stop filling the stratosphere with greenhouse gases and turning it into a blanket, these mechanisms will bring temperatures down quickly.

The maximum surface temperature of the ocean is about 38C. At this point the cooling mechanism called a tropical storm kicks in. That's why, as temperatures rise, storms have been getting more frequent, more severe, and moving further away from the tropics.

And the cooling mechanism for the oceans themselves is called an ocean gyre. The one I know is the North Atlantic gyre, composed of the Humboldt current taking cold Arctic water down to the equator, and the Gulf Stream bringing warm equatorial water to the Arctic.

Once the stratosphere is dumping heat, not radiating it back to the surface, we should start getting polar blizzards recreating the ice caps, and the gyres reasserting themselves (the North Altlantic gyre is in serious trouble thanks to the loss of the Arctic ice cap). At which point we could find ourselves heading rapidly into another ice age. Or not as the case may be.

Cheers,
Wol


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