Addressing worshippers in St Peter's Square, the pope urged people to pray that the UN conference "may give effective answers offering concrete hope to future generations".
Pope Francis on Sunday urged people to pray so that "the cry of the Earth" is heard at the UN climate summit getting underway in Glasgow.
Addressing worshippers in St Peter's Square, the pontiff said he hoped the crucial conference can offer "effective answers" for future generations.
"Today in Glasgow, in Scotland, the UN Summit on Climate Change is starting, COP26. Let us pray so that the cry of the Earth and the cry of the poor will be heard and that this meeting may give effective answers offering concrete hope to future generations," he said.
Francis has made care for the planet's fragile environment a key plank of his papacy.
"It is time to act, and to act together" against climate change, the COVID-19 pandemic and poverty, Pope Francis also warned in a text made public on Sunday by the Italian daily Il Corriere della Sera.
Denouncing "an ecological crisis" and "a social crisis (...) made deadly by a health crisis", the pope said that these crises also represent "opportunities" and a chance to "learn from mistakes committed in the past".
"It is time to think big, to rethink our priorities (...) and to re-plan our future. It is time to act, to act together, it is time", concluded the spiritual leader of the world's estimated 1.3 billion Catholics.
The appeal from the pope came as G20 leaders, meeting at their summit in Rome, agreed on a goal of limiting global warming this century to 1.5 degrees above pre-industrial levels.
The heads of the world's 20 richest nations, which account for more than 75% of greenhouse emissions, were negotiating on what commitments they are willing to make to contain rising global temperatures. What they agree is seen as vitally important in setting the tone for COP26 negotiations in Glasgow.
The Pope also said he was thinking of the people of Haiti and urged the world not to abandon them.
He also said he was praying for people who had suffered as a result of flooding in recent weeks in Vietnam and Sicily.