OSLO (Reuters) - Investors managing more than $13 trillion of assets urged leaders of the Group of 20 on Wednesday to ratify a global climate deal by the end of 2016 and to step up efforts to shift from fossil fuels.

A total of 130 investors, grouped in six coalitions, wrote a letter to G20 leaders and also called on them to double global investment in clean energy, develop carbon pricing and phase out fossil fuel subsidies.

Among backers were the California Public Employees’ Retirement System, Swedish National pension funds, Aegon, AustralianSuper, the Church of England Pensions Board and the New York City Comptroller, it said.

“The Paris Agreement provides a clear signal to investors that the transition to the low-carbon clean energy economy is inevitable and already under way,” the investors wrote to G20 leaders before a Sept. 4-5 summit in China.

The letter called on the G20 to “complete your process for joining/ratifying the Paris Agreement in 2016 if possible.”

Many major emitters of greenhouse gases, led by China and the United States, have said they will formally join up to last December’s Paris Agreement on climate change this year.

But no G20 nation has yet completed the process. France has ratified but is waiting to submit documents with other European Union nations.

As of Tuesday, the United Nations says that 23 small nations representing only 1.1 percent of global emissions have completed the formalities. The deal requires at least 55 nations representing 55 percent of global emissions to become law.

The investors said that countries ratifying the Paris Agreement quickly would be “better able to attract investment in low and zero carbon energy solutions.”