How many billionaires would it take to save the planet?

Bloomberg’s Robin Hood Index calculated what slice of each top billionaire’s fortune would be needed to buy all the carbon credits required to offset all domestic greenhouse gas emissions in their home country over a year. One can only imagine what the most affluent in 44 countries, with an estimated wealth of $786 billion can do with their money that governments and agencies can’t.
 
The answer is quite a lot.
 
In developing countries such as Russia and India, gas mogul Leonid Mikhelson and oilman Mukesh Ambani have plenty of money to spare even after offsetting the emissions in