Global warming - melting of ice sheets? Flooding???

Peter B

I hope this is the right forum.

I understand that with global warming the temperature of the planet increases and the ice caps will start to melt.

What I don't understand is how this will lead to flooding. If the ice caps are not touching the sea floor when they melt they should not raise the sea level by 1cm let alone the 200 feet. Its like if you have ice in water in a glass and the ice melts, the level of the water does not change. It remains constant.

There must be something simple I'm missing here.

Can anyone help me?

Danno

If the ice sheets on land such as Antarctica and Greenland melted completely it would raise sea levels... but the ice is not melting. Global Warming is also a myth, they messed with the figures to make it look like the planet is warming.

Turtwig

Yeah you're missing quite a bit it must be said. :-)

The ice caps in the Arctic regions will melt and majority of glaciers will begin to recede. However, like the spelling of science there are exceptions to the every known rule. Some glaciers will grow, the Antarctic Ice Shelf will most likely grow in the near future as well even though the waters around it are unquestionably warming up. Certain aspects of reality just are counter intuitive to the classically tuned mind (I'm afraid that's all homo sapiens.). If I can find good links to the reasons behind the growth of Antarctic Ice Shelfs I will (Nasa and Noaa are always a good place to start).

Ok, before I get to the flooding bit one other thing needs to be pointed out. Ice caps melting will probably cause sea levels to rise, but not nearly as much as the thermal expansion of water that results from the increased ocean temperatures. Remember : water expands when heated.

Ahh now the flooding is a hazy one. Mostly influenced by misrepresentation of science and/or bad understanding in the media. To put it simply climatalogists predict that we'll see more extreme weather events as the climate changes. However, owing to the complex nature of precipitation they can't really accurately say what will be the case. Some climate models on precipitation in a given region disagree not by number but by sign. That is a huge hole which everyone would like to see filled.

Godge

Danno wrote: »

If the ice sheets on land such as Antarctica and Greenland melted completely it would raise sea levels... but the ice is not melting. Global Warming is also a myth, they messed with the figures to make it look like the planet is warming.

I don't think it is as simple as that. The fact is that climate changes over time. Whether the ice is melting or whether the earth is cooling or warming may not have much effect on people's lives in Ireland.

Even average global warming will allow for regional variations. For their latitude, Britain and Ireland have been warmer than they should be. Should Newfoundland and others at this latitude warm up on average by 3 degrees but Britain and Ireland revert to latitude norms, we could see significant overall global warming accompanied by significant cooling in these islands.

And that is the real problem with the models of climate change. Few of them can accurately model what has happened in the past to the earth's climate and those that come close still have questions to answer about how well they can predict the future.

Climate change is happening. It always has and always will at slower or faster rates. The scary thing is that nobody can accurately predict what it means for you and me.

Ask one of the experts on this forum for a more scientific explanation.

Deep Easterly

Malty_T wrote: »

Ok, before I get to the flooding bit one other thing needs to be pointed out. Ice caps melting will probably cause sea levels to rise, but not nearly as much as the thermal expansion of water that results from the increased ocean temperatures. Remember : water expands when heated.

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Water not only expands as it heats, but also evaporates, which in turn could have a cooling effect not only within the evaporative process, but also from increased precipitation. While this may not prevent completely any warming of SST's, it could slow it down significantly.

Turtwig

Deep Easterly wrote: »

Water not only expands as it heats, but also evaporates, which in turn could have a cooling effect not only within the evaporative process, but also from increased precipitation. While this may not prevent completely any warming of SST's, it could slow it down significantly.

Ok..two things firstly you're not going to get that much extra evaporation from a 1ºC change in temperature. Secondly water vapour happens to be the most influential green house gas in the atmosphere. Certainly not a cooling agent.

Deep Easterly

Malty_T wrote: »

Ok..two things firstly you're not going to get that much extra evaporation from a 1ºC change in temperature. Secondly water vapour happens to be the most influential green house gas in the atmosphere. Certainly not a cooling agent.

OK then. How much expansion of ocean would occur from a 1c increase?

Turtwig

Malty_T wrote: »

Ok, before I get to the flooding bit one other thing needs to be pointed out. Ice caps melting will probably cause sea levels to rise, but not nearly as much as the thermal expansion of water that results from the increased ocean temperatures. Remember : water expands when heated.

Wow.

My bad, thermal expansion is expected to account for only about 50% of current sea level rise (1961-2003). It appears to be an even split between that and ice melt.:o. I'd never have thought that to be case (given that the melted ice would also be subject to expansion) but it appears to be the case. That's actually pretty scary.

Turtwig

Peter B wrote: »

If the ice caps are not touching the sea floor when they melt they should not raise the sea level by 1cm let alone the 200 feet. Its like if you have ice in water in a glass and the ice melts, the level of the water does not change. It remains constant.

I forgot this bit before. The important thing to remember here is that water expands when frozen. The ice occupies a much larger volume than the same quantity of liquid water would. The level of water does change when you melt ice in a glass of water, it's just that the level of change is so small that you'd barely notice. However, given an ice shelf the size of Greenland, now if that were to melt entirely it would contribute to about an 8m rise in sea levels. There's that much ice.