Leaders of the Group of 20 rich countries called for "meaningful and effective" action to limit global warming at 1.5 degrees Celsius in a final communique seen by Reuters on Sunday ahead of its publication.

However, the communique contained few concrete actions and made no reference to a specific 2050 date to achieve net zero carbon emissions that scientists say is vital to stave off disastrous climate change.

The final document says current national plans on how to curb emissions will have to be strengthened "if necessary" and includes a pledge to halt financing of overseas coal-fired power generation by the end of this year.

"We recognize that the impacts of climate change at 1.5°C are much lower than at 2°C. Keeping 1.5°C within reach will require meaningful and effective actions and commitment by all countries," the communique said.