Chris Martin: The coffee market should be a great redistributor of money

From a talk by the singer of Coldplay at a benefit for Haitian coffee farmers in London

I have to admit I was scared. When Oxfam approached Coldplay to help promote their Fair Trade campaign, it seemed right. While we're promoting our new album we felt it would be good to have something useful to say in interviews. But flying out to the Caribbean to see the problem first-hand, I was terrified of turning into some kind of fourth-rate Bono blathering about issues I didn't really understand.

Yet actually being there made me see very clearly how smaller, poorer countries are ripped off by the trade rules that the Western countries impose. Coffee is a great example. Grown mainly in developing countries, it's consumed mainly in wealthy countries and should be a fantastic way of moving money from rich to poor. And it was, until the price of coffee on the world markets plummeted.

The poorest country in the Western hemisphere, Haiti's forests are vanishing, its cities are crumbling. It could be a beautiful Caribbean island, but in parts it looks like its been burned to the ground. The coffee-growing areas are still lush and beautiful, mainly because the bushes need shade to thrive. The farmers I met worked on tiny plots of mountain land where coffee grows alongside yams, bananas, cocoa, grapefruit, mangoes and coconuts. Most of this is used to feed their families, while coffee provides the cash to buy things they can't grow.

The massive drop in price means taking children out of school, treating illnesses with the out-of-date medicines, cutting down trees to burn for fuel. It means working harder than most of us could imagine for less money than we spend on a morning latte in Starbucks. No one I talked to wanted their children to do the same – they all hoped they'd leave Haiti and find work elsewhere.

But there was hope. I met some amazing people who were struggling to make a difference, and by paying a few pence more for Fair Trade coffee, we can ensure that the farmers get nearly three times as much for their crop. Whenever I was depressed by what I'd seen, Yolette Etienne, the inspiring woman who leads Oxfam's Haiti team, stressed the good small projects like the coffee co-ops we visited can do: "We've just got to do things bit by bit."