Visualising the amount of ice melting in Antarctica

Monday 19 May 2014 18.24 By George Lee
By George Lee, Agriculture and Environment Correspondent

The latest scientific analysis of the rate at which ice is disappearing from Antarctica shows that the continent is now losing about 160bn tonnes of ice per year to the ocean.

In a report published today in the journal Geophysical Research Letters, scientists used the most recent data collected by the European Space Agency’s Cryosat spacecraft to show that the rate of melt in Antarctica is now almost double the previous estimate.

However, it is very hard for most people to imagine how much 160bn tonnes of ice actually is or what that much ice might look like.

To put it into context consider the size of Liberty Hall in Dublin – one of the largest, most iconic, and most easily recognised buildings in the country.

It should not be too hard, given its shape, to imagine Liberty Hall as a huge ice cube in the heart of the capital city.

The amount of ice, however, being lost in Antarctic is equivalent to 8.7m ice cubes the size of Liberty Hall, every single year.

And if you laid those ice cubes out end-to-end they would stretch right around the world 13 times over.

That is more than 522,000km of ice cubes the exact size of Liberty Hall all in a row – enough to stretch to the moon and more than one third of the way back to earth.

That is how much ice is being lost every year from Antarctica alone.

Another way of trying to grapple with what is going on is to consider how much extra water 160bn tonnes of melting ice puts into the oceans.

It turns out that it is enough to cover an area equivalent to the entire island of Ireland under two meters of water every year. That is 20 meters in a decade from Antarctica alone.

All the scientific data suggests, however, that the rate at which the Antarctic ice is melting is accelerating rapidly.

And none of this takes into account the amount of ice melting from the Greenland ice sheet, or from glaciers all over the world.

The key finding today, however, is of course that the rate at which we are losing ice in the Antarctic, and by extension elsewhere is mind-boggling, and almost twice as fast as was previously believed.

The debate about whether or not all of this is manmade appears a little bit irrelevant in the context of what exactly is going go.

Surely the number one issue is what are we going to do about it?

Here’s the maths:

One tonne of ice = One cubic metre of ice.

160,000,000,000 tonnes of ice being lost in Antarctica = 160,000,000,000 cubic metres of ice.

Footprint of Liberty Hall is 17.5 metres by 17.5 metres.

Height of Liberty Hall is 60 metres.

Volume of Liberty Hall is 17.5 x 17.5 x 60 = 18,375 cubic metres.

160,000,000,000 divided by 18,375 = 8,707,483.

So we would need 8.7 million Liberty Halls to get a volume of 160 billion cubic metres.

8.7 million X 60 metres = 522,449,979 metres = 522,450 kilometres.

Circumference of the Earth = 40,075km.

522,450 km = 13 x 40,075km = 13 times around the world.

Distance to the moon = 384,400km.

Distance to the moon x 1.358 = 522,450km.

Area of Ireland = 84,431 square kilometres = 84.431 billion square metres.

Area of Ireland under one metre of water requires 84 billion cubic metres of water.

About 160 billion tonnes of ice is melting from Antarctica each year.

That is approximately 2 x 84 billion cubic metres.

One cubic metre of ice = One tonne of ice.

So 160 billion tonnes of ice would put an area equivalent to Ireland under 2 metres of water every year.