It is often said that the colour of money is green, but until recently the finance industry hasn't been well adapted to helping achieve policy objectives for the environment. 

New instruments have been developed to help mobilise financing for projects to mitigate climate change, some of which have caught on, but measuring their impact remains difficult.

Green bonds

Also known as climate bonds, these have quickly become the major weapon in the funding arsenal. Green bonds are debt issued to finance projects that have a positive impact on the environment. The amount issued has jumped in 2017, particularly in Europe.

"For 2017 the issuance of green debt has already reached 125 billion euros ($147 billion)" against 90 billion euros in 2016, said Stephane Marciel, who manages sustainable bonds at the commercial and investment banking unit of French lender Societe Generale.