A petition launched by Desmond Tutu urging global leaders to create a world run 100% on renewables within 35 years has been backed by more than 300,000 people globally.

It describes climate change as “one of the greatest moral challenges of our time”.

The petition on Change.org calls upon US president Barack Obama and UN secretary general Ban Ki-Moon to set a target of 100% renewable energy by 2050.

Tutu, the former archbishop of Cape Town and Nobel peace laureate who rose to fame for his anti-apartheid activism, said: “As responsible citizens of the world – sisters and brothers of one family, the human family, God’s family – we have a duty to persuade our leaders to lead us in a new direction: to help us abandon our collective addiction to fossil fuels. We can no longer continue feeding our addiction to fossil fuels as if there were no tomorrow. For there will be no tomorrow.”

The petition is one of many in a wider faith-based campaign led by religious leaders designed to increase pressure on politicians around the world to deliver a new global climate change agreement when they gather at a crunch summit at Paris in December. Leaders include the Supreme Patriarch of Cambodia Tep Vong, the former Grand Mufti of Egypt Sheikh Ali Gomaa and Cardinal Damasceno Assis, Archbishop of Aparecida in São Paulo, Brazil.

The petition reads: “Climate change is one of the greatest moral challenges of our time ... we need bold action like this to keep global temperature rise below the unacceptably dangerous tipping point of two degrees, to phase out carbon pollution to zero, and to invest resources in sustainable development pathways to build a more flourishing, inclusive and balanced world.”

At a summit in Bavaria in June, G7 leaders including Obama and German chancellor Angela Merkel pledged to end the use of fossil fuels by the end of the century. Although some environmental groups heralded it as a “historic” announcement that would send an important signal for faster worldwide action, critics have said that the transition to renewables needs to be quicker if the internationally agreed target to keep global warming within 2C is to be met.

The petition has also been backed by US actor Lindsey Shaw.