UN leader Ban Ki-moon said Saturday a super typhoon that killed thousands in the Philippines was an example of climate change and should serve as a warning to mankind.
Ban was speaking at the Tallin University in Estonia on a tour of several Baltic states before joining a second week of climate talks in Poland.
The UN chief said the world was facing a tipping point, as countries thrash out a deal to be signed in 2015 to cut Earth-warming greenhouse gas emissions.
"There are a lot of people on Earth who seem to believe we have two Earths," Ban said.
"We have seen now what has happened in the Philippines. It is an urgent warning," he said, "an example of changed weather and how climate change is affecting all of us on Earth."
The UN reported 4,460 people had been confirmed dead so far and said 2.5 million people still "urgently" required food assistance after the country was hit by Super Typhoon Haiyan on November 8.
The devastating typhoon -- the strongest ever to make landfall -- has been seized upon by climate change activists who have linked it to global warming.
While experts are hesitant to link extreme weather phenomena to climate change, the UN has said rising sea levels make coastal populations more vulnerable to storm surges.
The World Meteorological Organisation has estimated 2013 was on course to be one of the hottest years since records began and global sea levels reached a record high.
The latest round of UN talks to set new climate goals comes amid warnings a 2009 aim to limit warming to an increase of 2 degrees Celsius in the average global temperature is growing ever more elusive.
In September, the UN's Intergovernmental Panel on Climate Change predicted global surface temperatures could climb on average by as much as 4.8 C (8.6 F) this century -- a recipe for catastrophic heatwaves, floods, droughts and sea-level rise.
"We need action before it is too late," said the UN chief, adding a rise in temperatures would "affect us all. The threat is very real and we all have to take responsibility to stop it."
Ban said the United Nations had put in place a scientific advisory board of at least 30 scientists who will begin work in February to help the UN make decisions on protecting global resources and addressing the climate change threat.