The bank commissioned a report by the Climate Bonds Initiative, a non-profit organisation trying to encourage green investment.
The folks at the Climate Bonds Initiative think government involvement can help to kick-start the market.
But Mr Schwarzenegger made it more palatable for voters by packaging the bond initiative with Proposition 58.
California raised the stakes with a huge $3 billion bond initiative, and other states followed with ballot initiatives or legislation to give scientists grants or to build research centers.
The market is growing rapidly – in 2012, $74bn of climate bonds were issued, 25% more than the previous year, says Bridget Boulle, programme manager at the Climate Bonds Initiative.
The climate bonds initiative (CBI) and HSBC said on Thursday that green bonds with a total value of $18.3bn£10.7bnbn) were issued in the first half of 2014.
Leggett's comments were echoed by Sean Kidney, chair of the Climate Bonds Initiative, which will this month launch new standards for green investment bonds.
Europe has taken a step in the right direction with the EU/EIB project bond initiative but for global policy action the World Bank could play a key role.
"Bonds are particularly suited for providing the capital for the long-term environmental infrastructure required to build a low-carbon, climate-resilient economy," says the Climate Bonds Initiative, which campaigns for more investment in low-carbon solutions.
Estimating the size of the market is hard: according to Climate Bonds Initiative (CBI), an NGO, between $10 billion and $30 billion of bonds related to renewable-energy projects have been issued.
