Does melting of sea-based ice contribute to sea level rise?

Question

On which parts of the world are sea-based ice located, and where are the land-based ice located?

How about Greenland, the Arctic ice cap and Antarctica? Which of these are land-based, which are sea-based? Will the melting of all of these, or only some, contribute to global sea level rise in the 21st century?

Answer 1

LAND BASED ICE
Greenland, Antractic ice sheets, glaciers and snowfields.

SEA BASED ICE
Arctic, Antractic ice shelves, icebergs, icefloes and other forms of sea ice.

CHANGES IN SEA LEVELS
The average global sea level increase is currently 3.1mm (⅛ inch) a year and increasing. It's expected that by 2050 sea levels will be rising by 6mm (¼ inch) a year and by 2100 it will be 12mm (½ inch) a year.

Following the retreat of the glaciers some 10,000 to 18,000 years ago the sea levels rose and flooded much of the land. Since then sea level rises have slowed and for the last few thousand years have averaged less than 1mm a year.

SEA LEVEL RISES
Just over half of the current sea level rise is due to thermal expansion of the seas and oceans, the remainder is due to the introduction of more water to the seas and oceans. This is partially offset by isostatic uplift - the rising up of the land due to the reduction in weight caused when the ice on the land melts.

THE ARCTIC
This is a floating mass of ice and as such it's already displacing it's own mass of sea water. It's currently melting at record rates, if the melting of last season is repeated then there's only 23 more years before the Arctic Ice melts completely each summer. Current scientific opinion is that there's 40 years before it melts each season.

GREENLAND
Again, there is record melting here. 1000 years ago when the Vikings settled there were ice free areas in the southwest of the country, today virtually the entire coastline is free of ice and the ice-free coastal strip extends 200km inland in places.

Last year 220 billion tons of ice were lost from Greenland. The ice here is an 'ice sheet' meaning it's a large land-based mass of ice. Bacause it's land based, any ice that melts is added to the seas and oceans as meltwater runoff. If the whole of Greenland were to melt then sea levels would rise by 6.55 metres (20 feet).

ANTARCTICA
This consists both of ice sheets and ice shelves. The difference between the two being that shelves are over water whereas sheets are over land.

The Ice shelves, like the Arctic, are floating and thus displacing their own mass of water, and just like the Arctic, they too can melt completely and sea levels would be unaffected.

There is an annual net loss of ice from Antarctica currently running at approx 80 billion tons a year. This is considerably less than Greenland despite Antarctica being much larger. The reasons being that global warming has led to increased precipitation and so more snow is falling on Antractica than used to fall, this increased snowfall is compensating for a lot of the melting that is occurring. Also, Greenland has warmed more than Antarctica and so is melting quicker.

Antarctica is generally divided into three parts - the Peninsular and the East and West Ice Sheets. The East Ice Sheet covers the largest area and if all of this melted it would raise global sea levels by 64.9 metres (210 feet). If the whole of Antractica melted then sea levels would rise by 73.4 metres (240 feet).

GLACIERS AND SNOWFIELDS
Despite all those impressive snow capped mountain ranges around the world they don't hold much snow and ice compared to the polar regions. If it all melted then sea levels would rise by 0.45 metres (18 inches).

Answer 2

The floating ice displaces water, so melting it doesn't change the sea level, but it does mess up the salinity on a local level. It also drastically changes the albedo (reflectivity) of the planet so that more solar energy is absorbed (rather than reflected back into space by the white ice. This additional energy absorption will accelerate the warming, possibly in a "tipping point" manner where a little extra energy input causes things to very quickly go beyond the point of recovery (as in when you stand a book up on end and push the top a little bit at a time until it suddenly gets tipped too far and it crashes down.)

Melting land-based ice caps like Antarctica will raise the sea level.

Answer 3

The ice in the water already, does not affect sea levels ,such as the Arctic ice.

But most of it is outside above the seas and when this melting ice returns to the seas it will affect sea levels ,

The ice in Green land and Antarctica is 2 kilometers high in places ,that is a lot of water ,so are the mountain glaziers and all the permafrost places ,like tundras

Answer 4

Floating ice displaces a volume of water equal to its mass, so when it melts, sea level does not rise. But when the great land-based ice masses on Greenland and Antarctica melt, we are in deep doodoo.

Answer 5

No, sea based doesn't significantly contribute.

The Arctic ice cap is sea based. Greenland and Antarctica both consist of land based ice.

Answer 6

If Global Warming is kept up it should,It's a ice cap, it contains water, once that frozen water melts it will set off into sea water rising sea level, Thank goodness I live in the mile high state!

Answer 7

i don't think it will raise the sea level - but if it is hot enough to melt ice - then that ice will form a water vapor which will and is turning many parts of the earth into a sauna - the sauna effect may create rain that will cause flooding in some parts of the world and droughts in other parts.

Answer 8

yes , it does & it is becoz of us & if the melting of ice is carried on like this only we will see no polar bear becoz if there is no ice there is nopolar bear & becoz of global warming &the biggest ice in the wrld which wold never brake it broke into two pieces & this is becoz of global wrming it may nt match ur question perfectly but it is the truth & global warming is groing on great xtend & if nt stopped then the wrld & the earth will come to an end so plz help the earth by decrease the global wrmng

Answer 9

Sea levels today are 30cm less than recorded levels from 165 years ago.

Answer 10

well, maybe 6-21 inches...