A group of 130 institutions that control US$13tn of investments have called on G20 nations to ratify the Paris agreement this year and accelerate investment in clean energy and forced disclosure of climate-related financial risk.

Countries that ratified the Paris agreement early would benefit from better policy certainty and would attract investment in low-carbon technology, the signatories said in a letter before the G20 heads of government meeting in September.

They called for strong carbon pricing to be implemented, as well as regulations that encouraged energy efficiency and renewable energy. Plans for how to phase out fossil fuels also needed to be developed, they said.

Financial regulators needed to force companies to disclose how climate change, and climate-related policies, would impact their bottom line, the group said.

“So investors are asking companies: tell us what the implementation of the Paris agreement means for your business so that we can price that risk and invest accordingly,” said Emma Herd, the chief executive of the Investor Group on Climate Change (IGCC) – one of the six organisations that represent the 130 investors on the letter.

Herd said that required not only mandatory reporting but also for that reporting to be standardised so that investors can compare between companies and between industries.

The signatories of the letter wrote: “The Paris agreement on climate change provides a clear signal to investors that the transition to the low-carbon, clean energy economy is inevitable and already under way.

“Governments have a responsibility to work with the private sector to ensure that this transition happens fast enough to catalyse the significant investment required to achieve the Paris agreement’s goals.”

The letter called on G20 countries to begin preparing to strengthen their emissions targets, as was required by Paris. It also called for them to double investment in clean energy by 2020, as the UN secretary general, Ban Ki-moon, urged in January.

The G20 leaders summit will take place in China on 4 to 5 September. Under China’s leadership, this year’s G20 has had a strong focus on climate-related issues, establishing a green finance study group.

“The nations that form the G20 are highly influential in achieving the full coming into force of the Paris agreement,” Herd said. “So if the G20 nations did actually all ratify Paris, then it would go a long way, if not get it across the line, of full implementation.”

The investor group called for Germany, which takes over the G20 leadership next year, to continue and strengthen the focus on climate change.