### Hamsters and Chessboards

Almost anyone who has studied mathematics will know the story of Sissa’s chessboard. As legend has it, King Shirham of Persia was so delighted with his minister of state Sissa Ben Dahir for inventing the game chess, he offered him a reward.

Majesty, I would be happy if you were to give me a grain of rice to place on the first square of the chessboard,’ said Sissa ‘and two grains of rice to place on the second square, and four grains of rice to place on the third, and eight grains of rice to place on the fourth, and so on for the sixty-four squares.’

The astonished King replied, ‘Sissa, you fool. Is that all you wish?

Of course, the King didn’t understand geometric progression and accidently promised Sissa 18,446,744,073,709,551,615 grains of rice.

Let’s assume that each grain of rice is weighs just 1 gram. Sissa would have walked away with over 18 trillion (1012) tonnes of rice.

Sissa’s chessboard illustrates that with exponential growth, things grow out of all proportion, and fast.

The Birth of a Rampaging Rodent

On a cold winter’s day in 2008, Andrew Simms, nef (the new economics foundation) Fellow, and my then boss set me a challenge. ‘What would happen’ he asked, ‘if a hamster didn’t stop growing?’ ‘Think about it,’ he said, ‘wouldn’t it be a fantastic way of illustrating the fallacy of infinite economic growth on a finite planet’.  I nodded furiously.

Now, anyone who loves number crunching will appreciate the delight at which I approached Andrew’s challenge. I set about researching the growth rate of a hamster from birth until puberty, and the calorific intake of a hamster per gram of body weight. And within an hour I had the answer.

From birth to puberty, a hamster doubles its weight each week. With a birth weight of 2 grams, by week 6 (approximate age of puberty), the hamster weighs in at 128g. If, then, instead of levelling-off in maturity as animals do, the hamster continued to double its weight each week, on its first birthday the hamster would be just over 9 billion tonnes. Now hamsters need around 1 gram of cereal for every 10g of body weight. So by the end of week 52, the hamster would require 900 million tonnes of cereal each day! In 2003, global corn production was just 700 million tonnes.

I re-did my calculations over and over again. For almost a year. I was right. Neither Andrew nor I could quite believe it, even though we were both familiar with Sissa’s chessboard.

To coincide with the launch of our report ‘Growth isn’t Possible’, we decided to translate the hamster into an animation. Working with award winning animator, Leo Murray, Impossible the Hamster was born.

We wanted to confront people with the meaning and logical conclusion of the promise of endless economic growth. We used a hamster to illustrate what would happen if there were no limits to growth. As things are in nature, sooner or later, so they must be in the economy.

As economic growth rises, we are pushing the planet ever closer to, and beyond some very real environmental limits. With every doubling in the global economy we use the equivalent in resources of all of the previous doublings combined.

Now Impossible the Hamster has taken on the radio play.

Building on our animation, talented director and producer Boz Temple-Morris and up-and-coming playwright Anders Lustgarten have collaborated to produce an incredible 45 minute radio play. The play will be aired on BBC Radio 4 on 1st December at 2.15pm. Andrew and I were fortunate enough to hear a ‘private listening’ earlier this week and it really was something quite special. I’m still lost for words.

The team have done an amazing job at weaving many of nef’s key themes into what is a slightly comic, surreal drama.

Tune in, let us know what you think…or be devoured by a rampaging rodent.