ROME, Oct 31 (Reuters) - Leaders of the Group of 20 major economies agreed on a final statement on Sunday that urged "meaningful and effective" action to limit global warming, but angering climate activistsby offering few concrete commitments.

The result of days of tough negotiation among diplomats leaves huge work to be done at the broader United Nations COP26 climate summit in Scotland, which starts this week.

U.S. President Joe Biden said he was disappointed that more could not have been done and blamed China and Russia for not bringing proposals to the table.

"The disappointment relates to the fact that Russia and … China basically didn’t show up in terms of any commitments to deal with climate change," Biden told reporters.

Although the G20 pledged to stop financing coal power overseas, they set no timetable for phasing it out at home, and watered down the wording on a promise to reduce emissions of methane - another potent greenhouse gas.

However, Italian Prime Minister Mario Draghi, who chaired the Rome gathering, hailed the final accord, saying that for the first time all G20 states had agreed on the importance of capping global warming at the 1.5 degrees Celsius level that scientists say is vital to avoid disaster.

"We made sure that our dreams are not only alive but they are progressing," Draghi told a closing news conference, brushing off criticism from environmentalists that the G20 had not gone nearly far enough to resolve the crisis.

The G20, which includes Brazil, China, India, Germany and the United States, accounts for 60% of the world's population and an estimated 80% of global greenhouse gas emissions.

The 1.5C threshold is what UN experts say must be met to avoid a dramatic acceleration of extreme climate events like droughts, storms and floods, and to reach it they recommend net zero emissions should be achieved by 2050.

The stakes are huge - among them the very survival of low-lying countries, the impact on economic livelihoods the world over and the stability of the global financial system.

"This was a moment for the G20 to act with the responsibility they have as the biggest emitters, yet we only see half-measures rather than concrete urgent action," said Friederike Roder, vice president of sustainable development advocacy group Global Citizen.

The final summit document said current national plans on how to curb emissions will have to be strengthened "if necessary" and makes no specific reference to 2050 as a date to achieve net zero carbon emissions.

"We recognise 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.