Next Friday, dozens of world leaders will gather in New York to officially sign the U.N. climate deal they hashed out in Paris last December. But the Paris Agreement will have only limited impact unless the world figures out a way to pony up the money necessary for a global transition to clean energy. Analysts put the price tag around $1 trillion annually through 2050.

The researchers behind the New Climate Economy, an initiative of the Global Commission on the Economy and Climate, think they know how to get those ponies in line. In a report released Wednesday, they write that the key to generating investment in clean energy is making the investments less risky; not digging up new money per se. There’s plenty of private investment money that could be channeled toward clean energy — hiding anywhere from pension funds to insurance companies’ portfolios. National governments, multilateral development banks (MDBs) like the World Bank, and others just need to figure out how to steer it in the right direction.

Part of the challenge is that many investors currently think of renewable projects the same way they think about fossil fuel projects, write the authors of the report. Investing in the energy sector is investing in the energy sector, the logic goes. But because fuel is free for many types of renewable energy, up to 90 percent of the costs for these projects are borne up front, and that makes them fundamentally different investments from other types of energy infrastructure.