Water on the planet

[kwicky]

Is it possible to have more water on the planet than already exists so causing many countries to become forever waterlogged? Countries such as Bangladesh are currently experiencing massive rainfall and flooding. Is there a shift in water levels from one part of the world to another? In putting this question I do not take the melting of polar ice regions or glaciers into the equation.

[gumboot]

As far as I remember from my schooldays, seawater evaporates to form clouds and rain falls from clouds back onto the land and sea. The rain that falls on the land finds it way back to the sea eventually. I think that's the gist of it anyhow.

I appreciate what you say in your last sentence, but I can't help feeling that the melting of icecaps and glaciers must be raising the sealevel. Just look at the size of those chunks of ice that hit that cruise-liner last week - this ice has to melt and have an effect on the overall sea level the world over, and this apparently is happening daily according to the global warming theorists.

It appears to follow that if there is a greater volume of water in the sea, there is more to evaporate to form clouds. Ergo, with more water in the clouds, there is more rain to fall on the land causing these floods in Bangladesh and Tewkesbury if it comes to that!

So I suppose no, it's not possible to have more water on the planet than already exists if we are speaking of the sum of liquid water, ice and water vapour combined. However, if you're thinking of liquid water alone, yes it can be increased by the melting of glaciers and ice caps.

I await correction with trepidition!

[chamois]

http://www.madsci.org/posts/archives/2004-04/1 082539819.Es.r.html

[wildwood]

Pity you don't want to include the ice in the polar regions. The antarctic continent covers an area equal to about 4% of the worlds oceans area. The average thickness of the ice there is one mile. By my reckoning if it all melts it will rise the world's water level by over 40 metres, this includes water which will cover 90% of the what is presently land.

[jake-the-peg]

The amount of water on the planet is pretty much fixed.

The flooding issue in Bangladesh comes from other causes than an increase in the global amount of water.

Bangladesh is very low lying and is on a delta where the Ganges and the Brahmaputra both reach the sea.

In the summer there are monsoon rains that bring large amounts of water and this coincides with melt waters swelling the rivers.

Finally if you look at the map you'll see that Bangladesh is at the neck of a funnel which can rise the sea levels especially with spring tides.

Add this little lot together and it's easy to see why Bangladesh is prone to flooding.

Now Human effects make this even worse. Deforrestation in places like Nepal and Tibet means that melt water is no longer slowly released into the rivers but can flood down suddenly.

As average temperatures rise more water is absorbed into the atmosphere and monsoons become heavier

And finally development in Bangladesh itself may prevent water draining as well as it did in the past.

So you don't need to consider melting ice caps into consideration to understand this but currently there is a 3mm per year average sea level rise going on, remembering that 70% of Bangladesh is less than 1m above sea level this will start to have a bigger effect as time moves on.

[kwicky]

I find it strange that the experts say the rise in sea levels are already increasing and set to accelerate further but what are governments doing about the problem? The melting of the ice caps and global warming just add to the problem. Measurements are taken from previous high water marks. If we cannot sove global warming at least we can build adequate defences!

http://news.bbc.co.uk/1/hi/sci/tech/4651876.st m

[Ethel]

The water that comes out of the tap has been here since the start.

It has been drunk by dinosaurs and passed through your granny.

There is no more and no less water than there ever was.

[kwicky]

If the amount of water in the system is not increasing land masses are certainly changing. It was proved that Southern England is tipping downwards at the expense of the North of Britain so expect greater flooding there.

[neuron]

Ethel, with all due respect, the issue was not about whether there is more water here now than sometime in the past. Common sense dictates that that cannot be the case.

However, what's important is how much of that water is tied up in normally inaccessible phase ie ice. For millions of years, icebergs and glaciers have remained in the ice phase making negligible difference to the volume of liquid phase water on the planet.

Global warming is said to be changing all that and the thawing of icebergs and glaciers is said be increasing sea levels throughout the world.

[neuron]

Incidentally, in yesterday's Daily Telegraph, there's a report about a meeting of the Intergovernmental Panel on Climate Change organised by the British Antarctic Survey.

A speaker at the meeting, Dr Tim Lenton of the University of East Anglia discussed the issue of the melting of the Greenland Ice Sheet ( a remnant of the last ice age) within the next three centuries. Dr Lenton stated that:

"if the climate change crisis reached the point of no return and it (the greenland ice sheet) were to melt, then global sea levels would rise by 22ft and swallow up most of the world's coastal regions".

Now this scientist is one of a team of eminent world scientists who are of the same opinion on this issue.

Evidently, this group of scientists believes that the melting of major masses of ice WILL increase sea levels. Clearly gumboot is au fait with current opinion on this matter.

[kwicky]

But I'm still perplexed how the rise in sea levels have been increasing for centuries long before the talk of global warming and the melting of the ice caps?