UN chief says heat is on and we must act now

In a message to the conference in Stockholm, secretary general of the UN Ban Ki-moon sent his best wishes and gratitude to the IPCC, and said the “world’s eyes” are on the city today.

“Since 1990 the IPCC has provided regular, unbiased assessment of the mounting impact of a warming planet.

“You are the world’s authorities on climate change, recognised with a Nobel Peace Prize,” he said, adding: “We need to build resilience and seize the opportunities of a low-carbon future.”

Concluding, he said: “The heat is on. Now we must act.”

Michel Jarraud, secretary general of the World Meteorological Organisation, said: “We have gone a long way [in the last 25 years in] our knowledge of the climate system [and] the human role in climate change.

“This report confirms, and you’ll hear a lot more about it, with even more certainty than in the past, that it is extremely likely that the changes in our climate system for the past half a century are due to human influence.

“And it should serve for yet another wake-up call that our activities today will have a profound impact on society, not only for us, but for many generations to come.”

Mr Jarraud said the decade from 2001-2010 was the warmest on record, and said more temperature records were broken than in any previous decade.

He said: “The IPCC report demonstrates we must greatly reduce global emissions in order to avoid the worst effects of climate change.”

Achim Steiner, executive director of the UN Environment Programme, described the report as a “dramatic reminder of both the significance, the pace, and also our ability to increasingly understand what is happening to our planet”.

He said: “For humanity to take decisions, perfect knowledge can never be the condition.”

Rajendra K Pachauri, chairman of the IPCC, said “almost 60%” of the authors in this assessment are new to the IPCC and bring “fresh perspectives”.