From yesterday's news - the first report on global warming by an economist. Long and the short of it? Don't do anything and it could cost us 20% of global GDP, spend 1% of global GDP now and avoid the whole disaster.

A report by economist Sir Nicholas Stern suggests that global warming could shrink the global economy by 20%.

But taking action now would cost just 1% of global gross domestic product, the 700-page study says.

Full story on BBC News