United Nations secretary-general Antonio Guterres demands humanity ends its "war on nature" in 2021 and urges world leaders to commit to a future with zero carbon emissions.

In a speech on the state of the planet at Columbia University in New York Wednesday, Guterres also urged people to prioritize "making peace with nature.

"Humanity is waging war on nature," declared Guterres.

"This is suicidal. Nature always strikes back - and it is already doing so with growing force and fury," he said.

Guterres said evidence of humanity's war can be seen in overfished oceans choking with plastic waste and acidifying owing to excessive amounts of CO2 in the atmosphere and in air and water pollution. Humanity is also destroying itself by destroying nature.

"Air and water pollution are killing 9 million people annually - more than six times the current toll of the pandemic," said Guterres.

"And with people and livestock encroaching further into animal habitats and disrupting wild spaces, we could see more viruses and other disease-causing agents jump from animals to humans."

Nature's revenge on humanity is manifested as biodiversity collapses, species extinction, desertification and massive forest degradation.

"To put it simply, the state of the planet is broken," Guterres said.

He said the fallout from this unwarranted "assault on our planet" was impeding UN efforts to end poverty, ensure food security and limit instability and displacement. He emphasized the largest effects of this war are falling most heavily on the world's vulnerable populations.

"Let's be clear: human activities are at the root of our descent toward chaos. But that means human action can help solve it," he said.

"Making peace with nature is the defining task of the 21st century. It must be the top, top priority for everyone, everywhere."

The raging COVID-19 pandemic is only one among many terrors devastating the planet. Added to the pandemic are new heights of global heating, new lows of ecological degradation and new setbacks in the effort toward global goals for more equitable, inclusive and sustainable development," according to Guterres.

The pandemic is also affording humanity the opportunity to heal nature by slowing down industries that release CO2 and other warming gases into the atmosphere

Guterres said countries that don't act now risked losing the opportunity afforded by the pandemic to reset their priorities on climate change and environmental protections.

"COVID recovery and our planet's repair can be two sides of the same coin," he said.

He said, however, there have been "worrying signs" some countries are using the crisis to eliminate environmental protections. Some countries are expanding their exploitation of natural resources as the pandemic rages.

"There can be no separating climate action from the larger planetary picture. Everything is interlinked - the global commons and global well-being," he said.

Now is the time to "flick the green switch" and transform the world economy into a sustainable one driven by renewable energy for the sake of future generations that will pay the price for today's mistakes or inaction.

"Nature feeds us, clothes us, quenches our thirst, generates our oxygen, shapes our culture and our faiths and forges our very identity. 2020 was to have been a 'super year' for nature. The pandemic has had other plans for us.

"Now we must use 2021 to address our planetary emergency."

Guterres said countries will meet in Kunming, China in May 2021 to forge a framework to protect biodiversity and halt the rampant extinction of species. He said the world failed to meet any of the global biodiversity targets set for 2020.