COP26 is 'last chance saloon', says Prince Charles
"We must now translate fine words into still finer actions," Prince Charles said.
The G20 bloc - which includes Brazil, China, India, Germany and the United States - accounts for an estimated 80% of the global gas emissions that scientists say must be sharply reduced to avoid climate catastrophe.
For that reason, this weekend's gathering is seen as a vital stepping stone to the UN's COP26 climate summit attended by almost 200 countries in Glasgow, where most G20 leaders will fly directly from Rome.
Prince Charles will speak at the opening ceremony of the summit on Monday (November 1) to welcome world leaders, his office said, a day after Queen Elizabeth pulled out on doctors' advice.
