With the ink barely dry on a land­mark cli­mate accord, nations now face an even more daunt­ing chal­lenge: how to get their indus­tries to go along.

If noth­ing else, ana­lysts and experts say, the accord is a sig­nal to busi­nesses and investors that the era of car­bon reduc­tion has arrived.

It will spur banks and invest­ment funds to shift their loan and stock port­fo­lios from coal and oil to the grow­ing indus­tries of renew­able energy like wind and solar. Util­i­ties them­selves will have to reduce their reliance on coal and more aggres­sively adopt renew­able sources of energy. Energy and tech­nol­ogy com­pa­nies will be pushed to make break­throughs to make bet­ter and cheaper bat­ter­ies that can store energy for use when it is needed. And automak­ers will have to develop elec­tric carsthat win broader accep­tance in the marketplace.

It’s very hard to go back­ward from some­thing like this,” said Nancy Pfund, man­ag­ing part­ner of DBL Part­ners, a ven­ture cap­i­tal firm that focuses on social, envi­ron­men­tal and eco­nomic devel­op­ment. “Peo­ple are board­ing this train, and it’s time to hop on if you want to have a thriv­ing, 21st-​​century economy.”