A thirsty thief is being blamed for downing a bottle of water, valued at £42,500, at a literary festival.

The two-litre clear plastic bottle containing melted ice from the Antarctic was devised to highlight global warming by artist Wayne Hill…

Its value was worked out by the artist from the damage worldwide of the entire ice sheet melting – he estimates between £6 trillion and £9 trillion – and the relative amount of damage from two litres of water.

Hmm. Something seems off about those numbers. Let’s check them!

A two liter bottle of water weighs two kilograms. At £42,500 for a bottle, that’s about £21,250 per kilogram. A cubic meter of water weighs a metric ton, or 1,000 kilograms. So a cubic meter of Antarctic meltwater is worth, by this artist’s standard, a little over £21 million (as of 2005).

How much ice would £9 trillion buy at that exchange rate? £9,000,000,000,000 divided by £21,000,000/m^3 is roughly half a million cubic meters. That works out to an 80 meter cube (about enough to fill a football stadium) or a one meter thick iceberg with a surface area of half a square kilometer (something you might see a forlorn polar bear wandering around on in a BBC documentary). A football stadium full of ice is pretty big…but not really enough to cover an entire continent. B-15, the largest iceberg on record, had a surface area of 11,000 square kilometers, and was probably more than 100 meters thick—take a look at the picture, and note that only about 10% of an iceberg is above water.

Well, maybe there’s a translation error. Maybe by ‘trillion’ the artist means not the American or scientific trillion, 10^12, but the continental trillion, 10^18, which is 1,000,000 times bigger. In that case, £9 trillion does buy you a few a big chunk of one B-15s worth of ice. That’s still not nearly enough to cover Antarctica; not even just the ice shelf around it. It’s also many orders of magnitude greater than the entire economic output of the human race since the dawn of recorded history.

Or, perhaps, the artist pulled the numbers out of thin air because they sounded impressive and he knew that nobody at a ‘literary festival’ would ever think to check. Certainly the BBC didn’t bother to.

He said: “The concept is to take something as dangerous as that and to bring it immediately into somebody’s presence.”

Or maybe the concept is to engage in hollow titillation of the audience’s self-concept as (in Neil Tennant’s words) The Persuaded We. If they actually gave a for-real damn, they’d apply simple arithmetic to test a contentious claim. Instead, they get to stare in mute, respectful silence at a bottle on a pedestal. This is how religions get started.