Around $90 trillion (£72.4tn) will need to be invested in sustainable infrastructure over the next 15 years to hit climate change targets such as the Paris Agreement.

A new report by the Global Commission on the Economy and Climate suggests how to overcome barriers to the huge investments needed in sustainable infrastructure.

This will have to be achieved by using public investment to help leverage further private investment, it states.

The report finds the Southern Hemisphere will account for nearly 70% of investment, with energy and transport sectors dominating.

It notes a single infrastructure project can require input from dozens of separate financial institutions and take more than a decade to build. The risk-return ratio for sustainable infrastructure is often too high to attract private capital.

The report identifies four actions that need putting into place: the removal of fossil fuel subsidies, the strengthening of policy frameworks, “greening” the financial system with carbon prices and green bonds and increasing investment in sustainable innovation to reduce the upfront costs of renewable infrastructure.

Lord Nicholas Stern, leading economist and co-Chair the Commission: “The next couple of decades and particularly the next two or three years, will be critical to the future of sustainable development. We can and should invest in and build cities where we can move and breathe and be productive while protecting the natural world that underpins our livelihoods.

“We cannot continue with ‘business as usual’ which will lock in high-carbon infrastructure and create further congestion and pollution, while choking off development opportunities, particularly for poor people. This will require not only better policies but also a sea change in the financial system itself to make it fit for purpose for the scale and quality of investment we now need. The development banks, both national and international, should be at the center of this: the growth story of the future.”

• green, Infrastructure, investment, sustainable