David Attenborough leads call for world to invest $500 billion a year to protect nature

British broadcaster David Attenborough led a call from conservation groups for the world to invest $500 billion a year to halt the destruction of nature.

Attenborough, whose new film A Life on Our Planet documents the dangers posed by climate change and the extinction of species, issued the call hours ahead of a UN summit aimed at galvanising action to protect wildlife.

"Our natural world is under greater pressure now than at any time in human history, and the future of the entire planet – on which every single one of us depends – is in grave jeopardy," he said in a statement.

"We still have an opportunity to reverse catastrophic biodiversity loss, but time is running out."

The call to redirect financing away from fossil fuels and other polluting industries and into locally-led conservation was launched by environmental group Flora & Fauna International and backed by more than 130 organisations.

The world spends an estimated $80-90 billion on conservation each year, but studies show that hundreds of billions of dollars may be needed to save ecosystems from collapse.

In a pre-recorded message to the one-day UN summit on Wednesday, British Prime Minister Boris Johnson said that there was growing evidence of a desire to avert "looming disaster".

"Let this be the day that action begins. And let us leave the next generation a world every bit as diverse and wondrous as the one we inherited," Johnson said.

Britain, Canada and others joined the European Union on Monday in pledging to protect 30 per cent of their land and seas by 2030. UN officials hope to secure a global agreement on that target at a major round of negotiations on biodiversity due to take place in China in 2021.