The world’s largest banks have issued billions in loans to sustainable businesses and taken some steps to restrict funding for some of world’s worst polluters. But the greening of global finance hasn’t reached the boardroom yet.

Executives with direct links to the clean-energy future rarely hold senior leadership positions or sit on the boards at 20 leading U.S. and European banks. Bloomberg Green analyzed the past and present professional affiliations of more than 600 directors and executives and found only a few with experience in renewable or sustainable industries.

Far more had ties to polluting industries: At least 73 have at one time or another held a position with one or more of the biggest corporate emitters of greenhouse gases, including 16 connected to oil or refining companies. The same 20 banks have helped arrange almost $1.4 trillion of debt financing for fossil fuel producers since the signing of the Paris climate agreement in 2015.

“Boards needn’t have a technical climate expert, but they do need to have a greater grasp of how climate impacts their businesses,” says Mark McKenzie, who heads accounting firm KPMG International Group’s global center on climate and sustainability. “Having someone with green experience at that top level—that buy-in—makes an enormous difference.”

Here are some of the bank boards from our analysis with the deepest ties to emitters—plus one company that’s produced more directors than anywhere else. The review focused on U.S. and European banks because they are the most active financiers of fossil-fuel companies and renewable energy producers.