The International Monetary Fund (IMF) calls on the leaders of the most polluting countries to adopt an international carbon floor price to combat climate changes.

The International Monetary Fund published on Friday a report calling on the leaders of the most polluting countries to adopt an international carbon floor price that would offer a "realistic prospect" for combating climate change.

Putting a price on carbon is now generally regarded as one of the most important instruments for dramatically reducing emissions of carbon dioxide, a major greenhouse gas.

"Our research shows that it is the most effective incentivizing tool to make progress towards decarbonization at the scale and pace needed to achieve the goals of the Paris Agreement," IMF Managing Director Kristalina Georgieva said on Saturday during the presentation of the paper.

But at the moment, four-fifths of emissions are free, and the world price of carbon averages three dollars a ton, far less than is needed to encourage innovation and investment in green energy or energy efficiency.

The IMF report evaluated different scenarios and gave the example of an agreement between six participants: Canada, China, the European Union, India, the UK and the US.

The international minimum price could be different depending on the level of development of the countries: $75 for high-income, $50 for emerging economies, and $25 for low-income countries.

According to Georgieva, the plan would allow emissions to be reduced by 23% by 2030, "in line with the goals of a global average temperature rise of less than two degrees Celsius."

Concluded in 2015, the Paris Agreement aims to limit warming below two degrees relative to the pre-industrial era. Achieving this goal involves "reducing emissions by 25% to 50% by 2030, in ten short years," it insisted. The IMF report suggests starting with the Group of 20 (G20) countries, before extending to others.

Defining a price for the ton of carbon emitted into the atmosphere is a way to tax the most polluting energies, with the aim of encouraging consumers and companies to use clean energies. But "a carbon floor price does not mean a carbon tax," the IMF director stressed. "Yes, taxes are an effective mechanism, we are in favor, but the minimum price can work through other measures, such as emissions trading," she said.

The plan presented by the IMF looks like an expanded version of the one adopted in Canada, where the price of carbon must progressively increase from $50 per ton of carbon in 2022 to $170 by 2030.