With a call to save the planet, Prince William and Pope Francis on Saturday joined activists, artists, celebrities and politicians in a free streamed TED event aimed at mobilising and unifying people to confront the climate crisis.

“The shared goals of our generation are clear,” William said in a video message kicking off the event, dubbed Countdown.

“Together we must protect and restore nature, clean our air, revive our oceans, build a waste-free world and fix our climate.”

For more than five hours the second-in-line to the British throne and other speakers delved in the reality of the climate crisis, the need for action, and what can be done.

Solutions posed included ways of farming that welcome wildlife as well as crops; transportation systems powered by electricity; cities designed for people instead of cars; economies that thrive by keeping the planet healthy instead of destroying it, and voting for political leaders keen to end the climate crisis.

“We are living during a historic moment marked by difficult challenges, as we all know,” Pope Francis said while urging people of all faiths to unite to protect Mother Earth.

“The world is shaken by the crisis caused by the Covid-19 pandemic, which highlights yet an even bigger challenge – the socio-environmental crisis.”

The Pope joined other speakers in saying the climate crisis is real and backed by science, and needs to be urgently confronted in ways that are socially just.

“The Earth must be worked and nursed, cultivated and protected,” the Pope said.

“We cannot continue to squeeze it like an orange.”

Countdown also focused on ways in which damage to the environment also fuels social and racial injustice.

British Parliament member David Lammy said: “Black people breathe the most toxic air relative to the general population, and it is people of colour who are most likely to suffer in the climate crisis.

“It gives all new meaning to the Black Lives Matter slogan ‘I can’t breathe’.”

Lammy called for climate and social justice leaders to join forces, and for a new international “ecocide” law to criminalise “the most severe actions against nature itself”.

Firms that make fortunes from fossil fuels or other greenhouse gas-emitting operations cause damage they don’t pay for, while funnelling money to politicians who help preserve the status quo, said another speaker, US economist Rebecca Henderson, who called on businesses to step up.

“We let capitalism turn into something monstrous,” she said, adding: “It’s going to be tough to keep free enterprise alive if most people believe the rich and the white are trashing the planet for their own benefit.”

Other speakers presented ways people can help stop slow down climate change.

The mayor of Freetown, Sierra Leone, for example, explained a project there to plant a million trees to protect against flooding and to absorb carbon dioxide.