When the traditional American mafia was at its apex, they would 'launder' their money through legitimate businesses. If a mafia drug lord wanted to have anything approaching a worthwhile life, cars and rings and goomahs, but did not want to go the route of Al Capone and be busted for tax evasion, he had to find a way to make enough money appear to be legitimate that the illegal money can be used. So they would invest in businesses that provided them with income that could be taxed and explain their lifestyles, allowing them to use the much greater illegal money.

That is tedious and time-consuming and so it became more common to use financial institutions like banks and shell companies. In the 21st century there is a new method; going green. Environmental groups are not going to ask a lot of questions if you want to create a company and then just sell your carbon credits.

That opened up a new criminal opportunity - the carbon trading market is so amateur that small-time crooks can just steal the credits from the carbon registry, the 'stock market' for carbon credits. 

Carbon trading is pretend money that can be turned into real money - a company like BP can be duped into buying stolen credits on the carbon stock exchange - and Europe's carbon trading ends up helping people even less than previously believed.

The Hack That Warmed the World By McKenzie Funk at ForeignPolicy.com