The world is "dangerously close" to running out of time to stop a climate change catastrophe, the UK government's climate chief Alok Sharma has said.
Mr Sharma - who is leading COP26, the climate summit hosted by the UK this year - said the effects were already clear with floods, fires and heatwaves.
"We can't afford to wait two years, five years, 10 years - this is the moment," he told the Observer.
But he did not condemn the government for allowing more fossil fuel projects.
And he defended his decision to travel to more than 30 countries in seven months.
Mr Sharma's interview with the Observer comes ahead of a major report being released on Monday from the United Nations' climate change researchers.
The report is set to be the strongest statement yet from the UN group on the science of climate change - and will likely give details about how the world's oceans, ice caps and land will change in the next decades.
The summary has been approved in a process involving scientists and representatives of 195 governments, which - having signed off on the findings - will be under pressure to take more action at COP26 in November.
Doug Parr, chief scientist with Greenpeace UK, said "world leaders have done a terrible job of listening" to warnings about climate change.
"This year, this has to change. We don't need more pledges, commitments and targets - we need real action right here right now."
Wildfires are currently raging in Greece, forcing thousands to evacuate their homes - and fires have also been burning in Turkey and California in the US. This summer, western Europe also saw its worst flooding in decades, which killed dozens of people.
Mr Sharma said if urgent action was not taken, the consequences would be "catastrophic".
"I don't think there's any other word for it," he said. "You're seeing on a daily basis what is happening across the world. Last year was the hottest on record, the last decade the hottest decade on record."
He added: "The important thing now is that rich world governments make up for lost time and act quickly to reduce emissions and deliver promised financial support for the vulnerable."