More than 3,500 UK churches have switched – or have registered to switch – their electricity source from fossil fuels to renewable energies, amid a new wave of Christian support for environmental activism.

Some 2,000 churches from 16 Catholic dioceses, the majority of Salvation Army facilities and a third of Quaker meeting houses have made the switch.

The figures, released by charities today, come alongside the official beginning of 'Creationtide', a season of celebrating creation, raising awareness of its plight and those most affected by climate change, which runs till October 4.

"There are many ways in which we may respond to the threat and the reality of climate change and adopting renewable energy for our church buildings must be a priority," said Rt Revd John Arnold, Bishop of Salford and chairman of Catholic aid agency CAFOD. He added that "by adopting renewable energy we will directly help people threatened, and most severely affected, by climate change".

The widespread Catholic support for green causes follows last year's encyclical from Pope Francis, Laudato Si, in which the pope called for a committed fight against global warming to protect "our common home". That encyclical was followed by the Catholic Church calling on the UN to agree a goal of 'complete decarbonisation' by 2050. September 1 has been marked by Pope Francis as the official World Day of Prayer for the Care of Creation (which the Orthodox church has celebrated since 1989). Pope Francis this week proposed adding care for the natural world to the seven "works of mercy" Catholics are meant to perform.

Many other church groups have joined the crusade; nearly 700 churches of various denominations have signed up up for new energy sources via http://www.bigchurchswitch.org.uk/, founded by Christian Aid and Tearfund. Christian Aid Chief Executive Loretta Minghella said: "We need a big shift to renewable energy and a shared commitment to leave the vast majority of fossil fuel reserves in the ground. This action by thousands of churches shows a groundswell of public support for renewables to which governments must respond by doing all they can to shift to a clean energy future."

Tearfund's Advocacy director Paul Cook called for urgent government action alongside church participation. "The longer we postpone, the worse it will be for our future and the future of people living in poverty around the world," he said.

The Church of England's lead bishop on environmental issues, Rt Revd Nicholas Holtam, said the groundswell marked "a shift in the Christian understanding of our relationship to creation under God", and invited Christians to "rediscover older traditions of a godly relationship of humanity to the wider created order".

He said: "One simple thing we can do in response to such a crisis is to switch to using clean energy in our homes, communities, schools and places of worship."