Global warming.

[Herbie]

Succintly put Herb. It's not the volume of melt water that's the real issue, but the addition of much colder / fresher water into the system that's the issue.

Whether we are the root cause of 'global warming' is hotly debated. The earths climate is something that's been fluctuating since time began, and that depends if you think the earth is 6000 years old or billions of years old.

It's an interesting topic, and when you consider that it was Maggies Government that poured £££'s into climate change research to quash the coal industry through CO2 emissions damaging the ozone layer, one wonders what the motives are now?

I agree with the topic, but youve opened an equally interesting topic there too then there is the volcano effect and much more,lets not get into plankton! all in all I think we are just in for whatever the cosmos has in store for us, though we cant do any harm cleaning our act up a bit.

 

[viscount17]

(thesis) it gets sufficiently warm for the polar caps to melt and for the Gulf Stream to submerge, then it will move south where (antithesis) it will pick up even more heat from the tropics and move north again?


(thesis) the gulf stream will move south leaving UK with a weather pattern similar to Canada but (antithesis) if the north has warmed sufficiently for the polar caps to melt, the north can't be as cold so Canada's weather is probably much as Scotland is now, so - golf's still on!

 

[Dave3498]

The floating ice around the North Pole has already displaced 9/10ths of it floating in. If it all melts, the water level will not rise at all.

Try this experiment: Put an ice cube in a glass and fill the glass to the brim with water, (the ice cube will stick ou slightly above the top of the glass.) Wait until the ice melts and see how much water spills over the glass. The answer is - none. Floating ice doesn't displace any water when it melts, it has already displaced the water by floating there in the first place.

 

[Herbie]

The floating ice around the North Pole has already displaced 9/10ths of it floating in. If it all melts, the water level will not rise at all.

Try this experiment: Put an ice cube in a glass and fill the glass to the brim with water, (the ice cube will stick ou slightly above the top of the glass.) Wait until the ice melts and see how much water spills over the glass. The answer is - none. Floating ice doesn't displace any water when it melts, it has already displaced the water by floating there in the first place.

Been there and done that several times and thats not the result I got. We are talking about a miniscule difference here that can barely be noticed unless in controled conditions.I have actually just done the test you indicate and there was barely any difference admittedly, but I knew this anyway,the difference there was, was a raised level however minute, the point is if you put something into something, you add to that something, the ice that forms the ice bergs is not created in the sea, its added, the ice you put in a drink is added and increases the level, the fact that it changes little or not at all as you suggest matters not, its already been added. Where bergs are concerned part of whats added evaporates and returns somewhere else later on, so its even more difficult to measure accurately.

When you add your ice cube to the drink does the level rise or fall or stay the same at that moment?

 

[backwoodsman]

The short answer is that if floating ice melts, then there'll be no level change.

Lets assume madandra has had a <u>very</u> big drink and has put a 1kg ice cube into it. By the laws of physics, an object immersed in a liquid displaces its own mass of the liquid (not its volume) So in this case it displaces 1kg of water. Because water expands on freezing it is slightly less dense than water so it floats and a little bit sticks out above the water. But it has still displaced 1kg of water.

When the 1kg of ice melts, it turns back into 1kg of water - ie exactly the same as the mass of water the ice displaced - so the level remains unchanged.

Ok, it goes a bit awry because glaciers are fresh water not sea water, so different density (which also means there may be a minute change in the level of your G&T as it is a different density to the purer water of the ice cubes) But the major problems are as others have said - changes in salinity etc, and that land-ice which melts, eventually runs into the sea - which will alter sea levels

 

[Tommo21]

I was right then eh.

 

[backwoodsman]

I was right then eh.

Nope. Melting icecaps is a serious business. Just in a different way than us all drowning... (which anyway could still happen if the antarctic ice melts as its continental ice rather than sea ice)

 

[Tommo21]

Scotland is not global then.

 

[Herbie]

The short answer is that if floating ice melts, then there'll be no level change.

Lets assume madandra has had a <u>very</u> big drink and has put a 1kg ice cube into it. By the laws of physics, an object immersed in a liquid displaces its own mass of the liquid (not its volume) So in this case it displaces 1kg of water. Because water expands on freezing it is slightly less dense than water so it floats and a little bit sticks out above the water. But it has still displaced 1kg of water.

When the 1kg of ice melts, it turns back into 1kg of water - ie exactly the same as the mass of water the ice displaced - so the level remains unchanged.

Ok, it goes a bit awry because glaciers are fresh water not sea water, so different density (which also means there may be a minute change in the level of your G&T as it is a different density to the purer water of the ice cubes) But the major problems are as others have said - changes in salinity etc, and that land-ice which melts, eventually runs into the sea - which will alter sea levels

You miss the point getting hung up with a ice cube in a glass theory, but you are wrong about 'no change', the fact that the ice is deposited in the sea raises the level, if all the ice and snow on land around the globe fell into the sea it would raise levels dramatically. I think I must be 'one of the others' mentioned as I think I was the first to mention salinity

There are other factors raising sea levels such as volcanic activity creating greater land masses, even new islands and constant underwater volcanic activity, erosion that is not redeposited on other land, any man made construction into the sea etc,everything deposited in the sea has an effect. The greater more imediate risk is that of rapid ice melt and the effect freshwater will have on the conveyor.