my god...

[Subdivisions]

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x117169

This is what urgency looks like. If we don't begin to take this seriously there is going to be a sea level rise of up to 15 feet. Goodbye Florida. Goodbye New York. Goodbye London. And that's just for starters. How about Shanghai, China?

[UncleSepp]

1. Amazing. Time to get on with "what now?"

Global warming is happening, and fast. The why of it is important, but how we as a planet handle the "what now" is going to determine how well we survive the effects of the climate change. We may be able to slow it by changing our practices, and we may not.

Clean air's good for beings who breathe. Frugal consumption is good for beings who consume any limited resource - in the long run, it's good for those who sell the limited resource, too. There's no long term down side to continuing to pursue the changes in our behavior that would help to reverse or slow down human-accelerated global warming. Let's go for it, for its own sake. Even if it doesn't work, we're still better off.

At the same time, I think we should start planning for what will happen if the changes we make do not slow climate change, or do not slow it enough to prevent such things as the expansion of deserts, the melting of permafrost, and the rise of sea levels. I think we need to start asking what coastal cities will do when the sea rises. What needs to be done to protect the city? What needs to be done to keep ports functioning? Can people and industry be moved? What planning needs to be done for when the breadbasket moves? How can we handle climate refugees?

I see so much energy going into politically-motivated blamestorming in the global warming debate, and very little into planning for the effects of global warming. Most of it seems to be coming from the right, but not all of it. In my opinion, it's time to shift the discussion to practical concerns. We have a mess on our hands, no matter whose fault it is or if it is anyone's fault at all, and the last thing this world needs is more hot air.

[happyslug]

2. The problem is all the red/purple could melt and have no affect on world wide ocean levels

The far is the Greenland ice sheet (All white in this picture) and the West Antarctic Ice Sheet (WAIS). Either one, if they should melt, would raise world wide ocean levels 15-20 feet. The even larger East Arctic Ice Sheet (EAIS) could raise world wide ocean levels over 200 feet (But in most models of Global warming the EAIS is expected to EXPAND in volume of Ice do to warmer air taking more water to the EAIS, The EAIS is completely within the Antarctic Circle AND above Sea level so is viewed as "safe" in most Global Warming situations).

The big fear is the West Antarctic Ice Sheet (WAIS). The WAIS is grounded BELOW sea level, so world wide ocean temperatures can affect it (Through this means getting through the Southern Ocean which circles Antarctica). Something happened 100,000 years ago, that suddenly the world wide Ocean levels went up 20 feet (and then down 200 feet within a Century and with that drop the Ice Age was on). This is called the "Madhouse Century". The present theory is the WAIS Collapsed do to Global Warming but the break up of the WAIS released so much nutrients into the South Pacific and Indian Oceans that you had a massive algae bloom that removed so much Carbon that the Ice Age started.

Right Now the South Pacific and South Indians Oceans (as you get closer to Antarctica) are ocean deserts, no large amount of Algae compared to the rest of the Oceans. The reason for this is believed to be that Algae closer to other Continents absorb all of the trace amounts of material living things need to live (i.e. dissolved Iron among other minerals). The Break up of the WAIS might do the same, i.e. raise world wide ocean levels AND then over the next 50 cause most of the exist Carbon in the air to be fixed by Algae so that we end up with a new Ice Age.

Thus the big question is next March, when the Antarctic iCe shelves are at their minimum, will this lead to the WAIS to break up? Will this cause world wide ocean levels to go up 20 feet (And maybe more depending on how the WAIS interacts with the EAIS, how much water of the EAIS does the WAIS block from going into the Ocean?).

My point is the Arctic Ocean can melt completely away and have no affect on world wide ocean levels, Why? THe Arctic is an Ice Shelf i.e. Ice Floating on water. As ice floating on water, the ice is already displacing the Water it will be when it melts. Thus no affect on world wide ocean levels. It is the ice Sheets, grounded on land, that is the concern, These if they melt or break up and starts to float, WILL DISPLACE WATER THEY WAR MADE OF. Since they are ice Sheets, they are NOT displacing that water NOW. This is the big Fear, will the WAIS break up next Spring? (Or some spring afterward)?

More on the Madhouse Century:
http://www.imaja.com/as/environment/can/journal/madhousecentury.html

[Subdivisions]

3. If it were only the Arctic ice cap, you would be correct.

But if the warming of the Arctic Ocean melts Greenland, that's when the trouble really begins. But there's more.

http://en.wikipedia.org/wiki/Thermohaline_circulation">The Thermohaline Circulation, also known as the "Ocean Conveyor Belt". If this circulation is interupted, Greenland could become as temperate as Europe is now and Europe could freeze over. The dilution of the freshwater from the Arctic ice cap into the surrounding seawater could also be a catalyst for disrupting the circulation.

[happyslug]

4. The real concern is the WAIS NOT Greenland

The reason for that is simple, Greenland as it melts will take decades to affect ocean levels. Its ability to break off suddenly and stop the world wide Conveyor belt is limited given that most of its ice Sheets are above sea level and as such NOT subject to a sudden dramatic flow into the Ocean. The best theory I have run across for the peaks of the Mini-Ice Age is that Greenland ice Sheets slowly expanded after 1100 but did NOT break into the Ocean till after 1300 (a Mini version of a much earlier Younger Dryas event) and this continued till the middle of the 1800s when the present warm period began.

More on the Mini-Ice Age:
http://en.wikipedia.org/wiki/Little_Ice_Age

The "next Ice Age":
http://discovermagazine.com/2002/sep/cover

Ocean Currents in the Arctic

http://www.whoi.edu/page.do?pid=12455&tid=282&cid=9206

More on the Younger Dryas event (10,700 to 9500 BC):
http://en.wikipedia.org/wiki/Younger_Dryas

More on the Madhouse century:
http://www.imaja.com/as/environment/can/journal/madhousecentury.html

Thus, while the Greenland Ice Sheet can slow down world wide ocean circulation, its ability to do more than slow it down disappeared when the North American Ice Sheet melted away about 10,000 years ago. The real concern is will the West Antarctic Ice Sheet (WAIS) do a rapid collapse and block the conveyor belt from the south? Only time will tell.