But they are not called icebergs until and unless they are floating in the sea. I was clear that land ice melting raises sea level. Obviously adding more water or ice to the sea does regardless of source.

The Maldives are coral atolls. This illustrates how those form. https://oceanservice.noaa.gov/educat..._coral04a.html

https://www.nationalgeographic.org/encyclopedia/atoll/

Interesting, thanks - is that going to happen to Hawaii in millions of years? (since they're also volcanic islands)

Randomly, Sean Carroll's podcast this week covers this topic. I'm taking a (free) Coursera course on the topic so the thread is appreciated.

https://twitter.com/seanmcarroll/sta...370361857?s=19

Naomi is a co-author of the great book merchants of doubt.

A melting iceberg also means that the water(former ice) gets warmer and therefore expands.

Water is denser than ice. That's why it's bad to let pipes freeze, and if you freeze a bottle of water the bottle will expand in volume.

Doesn't affect sea level. Put an ice cube in a glass of water and the water level raises by the volume of water displaced, that is the volume of water that weighs the same as the ice cube and not by the volume of the ice cube. So, as the ice cube melts it doesn't change the water level.

(The density of water changing because of water temperature change is a tiny effect here. In the ocean it adds up, but then it's mostly that warming means warmer oceans all around which means the ocean expands - and not about ice, icebergs or melting.)

This is true but what habs said is also true.

Trolly,

An iceberg displaces the weight of water at the temperature of the body it's floating in. If the iceberg were to melt immediately and to just above the freezing point it would then occupy a smaller volume than the same amount of water in the body of water (at some temp > 0 deg C) the ice had been floating in. Then it would warm to occupy the same volume of the water it had displaced originally - so no change in sea level.

That's ignoring some very small effects like, when the ice melting and then the melted ice warming would cool the rest of the ocean and lower sea levels. But, I imagine that's a very small effect even if all the icebergs in the world went into the ocean.

Habsfan seemed to be saying that the melting ice would increase the sea level because of the "expansion", when in fact the opposite of expansion happens and there is no increase in sea level.

The Northwest Hawaiian Islands (the oldest) already are apparently: https://en.wikipedia.org/wiki/Northw...waiian_Islands

I was thinking maybe the ocean around Hawaii was too cold for coral reefs but I guess not.

I know, but once it’s melted, the liquid water does expand with increasing temps, or at least that’s what I thought he was getting at.

No it doesn't, as has already been pointed out. And all the icebergs in the world melting won't change the ocean temperature enough to alter sea level. If anything the cause/effect is the other way around. If ocean water is warmed due to climate change, this could contribute to icebergs melting. The bulk of an iceberg's mass is already under water.

This is a little off from the original point that started this tangent, which is that some posters thought that melting icebergs raise sea level. It's been calculated (in a study someone linked earlier) that just due to the salinity difference, if all the icebergs in the world melted forever it might raise sea level 2 inches (once and done). But not because of more water, since icebergs are already in the water. Also, if we reach the point where all icebergs in the world melt, sea level won't matter anymore. We'll already be extinct or living on Mars.

It would not be one and done since new icebergs wold come from land ice.

Nope.

?

I believe I properly described why the result of a melting iceberg that is already floating is not higher sea levels, but water density does change as a function of temperature. It's a big factor in sea level rising.

Maybe you're getting at something else though.

You're gonna have to trust me on this one, Dave.

So why would an iceberg melt if the temperature doesnt go up? The iceberg remains ice if the temperature stays the same. So once the iceberg melted the water is part of the ocean and has the same temperature and continues to heat up if the earth continues on its path that to much heat remains within our atmosphere. The ocean temperature doesnt change by melting iceberg. Its volume increases and the temperature changes because water absorbs a lot of heat that cant excape earth atmosphere.
Correct me if I am wrong.

I think the major problem is Greenland right now since that ice mostly isnt in the water but melts at record speed.

A melting iceberg does not increase the volume of the ocean. First, it is already part of the ocean. Second, melting ice decreases its volume.

So?

No point other than correcting the poster who said that melting icebergs increase the volume of the ocean.

A cynical person might think you’re trying to downplay the problem of rising sea levels.

It's unrelated, and the tangent on melting icebergs wasn't started by me. I've expressed some opinions on rising sea levels also, but this wasn't part of it. In fact I've pointed out multiple times that melting icebergs aren't part of the sea level problem. This prompted someone to show me a study saying that the difference in salinity could in fact cause a minute and immaterial change in sea level, relative to the real issue. It was interesting and useful information, but not really relevant to the sea level problem.

Scintillating basic science debate here guys. I really feel like we might be onto something that climate scientists haven't thought of yet.