Tackling climate change and achieving the world’s sustainable development goals will require publicly funded and private sector banks and institutions to be far more willing to join forces to provide “blended” finance to projects, according to a new study.

Blended finance is the term given to the use of public or philanthropic capital to spur private sector investment in projects aimed at achieving the sustainable development goals. Already, this market is worth about $50bn globally, but experts said on Tuesday this sum could double within the next three to four years.

In a report to be presented on Wednesday at the World Economic Forum in Davos, the Business and Sustainable Development Commission found that private sector investors could take advantage of blended finance to gain access to rapidly growing markets in the developing world.

The commission has set up a taskforce specifically to consider blended finance and how to encourage growth in the sector. In its report, the taskforce found that there was great fragmentation across the market and called for public and private investors to pool their resources to create more giant funds, worth more than £1bn each, to take over from the smaller funds, of about $100m in size, which currently dominate the blended finance landscape.

There would still be a place for smaller funds, the taskforce said, but the creation of very large finance vehicles would facilitate bigger projects than are currently possible.

Lord Malloch-Brown, the former UK diplomat who chairs the commission, said: “Action is needed end-to-end across the whole investment system to scale up the use of blended finance, if we are serious about closing the funding gap for the sustainable development goals.”

He said gaining more private capital would be essential to achieving the sustainable development goals, especially regarding infrastructure in emerging economies.

The commission found that the market for blended finance had already doubled in size in the last five years, and that countries in the developing world wishing to take advantage of the funds available should prioritise investment in infrastructure that would increase resilience to climate change and provide environmentally sound economic development.

The group estimated that about $6tn a year would be needed to meet the sustainable development goals fully, and that a large proportion of this could be met by blended finance, if the market for the latter is spurred on by governments and companies.

Jeremy Oppenheim, founder of Systemiq, a financial institution focusing on sustainable development, and programme director at the Business and Sustainable Development Commission, said private sector banks and other financial institutions could benefit by pooling their resources with organisations from the public sector, such as development banks.

“There is a window of opportunity for institutional investors to increase their exposure to emerging markets infrastructure by taking advantage of the risk mitigation offered by blended finance,” said Oppenheim. “Momentum is growing – it is possible that the blended finance market could double again in the next three to four years.”

The paper produced by the taskforce, entitled Better Finance, Better World, is now open to consultation, which will be completed by the middle of March. After that, a report taking the responses to the consultation into account will be produced at the April meetings of the World Bank and International Monetary Fund.

The Business and Sustainable Development Commission was set up to further the sustainable development goals, and is funded by public sector organisations including the UN and World Bank, philanthropic bodies such as the Bill and Melinda Gates Foundation, and private sector companies including Unilever.

The sustainable development goals were adopted in 2015 by the UN, and include goals on ending poverty, protecting the planet and its resources, and ensure the long-term prosperity of humanity. All of the goals included in the package are supposed to be met by 2030.