We've seen the price of coffee drop for two principal reasons. Firstly, countries like Vietnam were encouraged by the World Bank to grow coffee. Secondly, mechanization in Brazil has massively increased their production.

It seems to me that mechanization is going to spread. All things being equal, that will cause the price of coffee to continue falling.

On the other hand, if we opened up our markets, that would help coffee producers switch to producing more profitable things, thereby increasing their incomes. Coffee farmers who exited the market would have an upward effect on the price of coffee, helping those who stay in the coffee industry.

Why slow down economic growth? Why not instead help poor countries grow too? We're seeing high economic growth in India and China - last year, this lifted millions out of poverty. Calls to slow down growth are misguided - and harmful.