They also mention 0.4% of world GDP as a gain; which fits with 180b$, but would imply that it is indeed a yearly figure - and thus we get to be in the same ballpark for what can only be a very rough estimate. In the long run, we're all dead. John Maynard Keynes
How about contributing the 0.4% gain towards the goal of 0.7% in development aid? guaranteed to evoke a violent reaction from police is to challenge their right to "define the situation." --- David Graeber citing Marc Cooper
Ploughing the gain into development aid: you'd need to persuade the Cairns Group nations to cough up, because they would be the ones in fact making the extra money.