Some 30,000 people, including prime ministers, presidents, businessmen and NGOs from around the world, are set to start negotiating on Monday at a major United Nations conference on climate change being held in Poland.
"Right now we are facing a man-made disaster of global scale, our greatest threat in thousands of years: Climate change", Attenborough said as the worldwide climate conference got underway with talks on how countries will implement the 2015 Paris Agreement limiting carbon emissions.
At his address at the climate talks yesterday, Mr Attenborough said: "The people have spoken: leaders of the world, you must lead, the continuation of our civilisations and the natural world upon which we depend are in your hands".
The climate change conference, COP24, will take place in Poland from December 2-14. Eighteen of the 19 warmest years on record have happened since 2000.
COP24 comes on the heels of the G-20 gathering in Argentina, where 19 of the 20 leaders signed a communique reaffirming their commitment to fight global warming, but President Donald Trump insisted on a paragraph outlining his opposition and the United States decision, under his administration, to withdraw from the 2015 Paris agreement.
The controversial tax is part of French President Emmanuel Macron's larger plan to reduce France's reliance on fossil fuels, in order to cut greenhouse gas emissions and fight climate change.
"This is our "we the people" message". One young man asked the camera, "Do you not see what is going on around you?"
Guterres named climate change as "the most important issue we face".
"Even as we witness devastating climate impacts causing havoc across the world, we are still not doing enough, nor moving fast enough, to prevent irreversible and catastrophic climate disruption", Mr Guterres said. "Time is running out", Attenborough said.
Israel launches operation to thwart Hizbollah tunnels from Lebanon
There was no immediate comment from Hezbollah and its Al-Manar TV did not make any mention of the Israeli operation. Israel also faces terror tunnels in the south from the Hamas terror organization in Gaza.
But US President Donald Trump's decision to withdraw from the Paris accord has dented trust among vulnerable nations, who fear there is not enough cash available to help them adapt to our heating planet.
"Leaders of the world, you must lead".
Many countries are already dealing with the droughts, higher seas and catastrophic storms climate change is exacerbating.
Guterres called on representatives to cement funding agreements, allowing the global community to take firm steps towards green solutions, suggesting the world was "nowhere near where it needs to be" on moving to a low-carbon economy.
"The good news is that we do know a lot of what we need to be able to do to get there", said David Waskow of the World Resources Institute.
Attenborough, who has produced and narrated numerous nature documentaries, is a strong advocate for fighting climate change - but that wasn't always the case. "Governments and investors need to bet on the green economy, not the gray".
COP24, the UN's annual climate summit, kicked off in Katowice, Poland.
The U.N. has a goal to raise $100 billion every year from 2020 for climate action.
The remark was also directed at host Poland, which relies on coal for 80 per cent of its energy. Polish coal company JSW is one of the main sponsors of the talks, which also does not bode well for COP24.