PARIS, Sept. 25 — A group representing some of the world’s leading banks will urge the United States and other industrial nations this week to move quickly to introduce a lightly regulated system for trading carbon emissions permits. Permit-trading systems offer banks a potentially vast new business. For it to grow, leading economies — particularly the United States — will need to set limits on the quantities of greenhouse gases that can be released and to allow companies in other parts of the world to buy emissions permits. “Where politicians opt to implement carbon constraints, then it should be cap-and-trade,”...