On Wednesday, Christian Aid launched its global prayer chain ahead of the UN's Climate conference, COP26, held in Glasgow in November.
Clergy, politicians and members of the public joined the charity as they held a prayer vigil at Parliament Square in London.
The former Archbishop of Canterbury Dr Rowan Williams addressed the crowd, as well as Christian Aid's CEO Amanda Khozi Mukawashi.
There was a time of worship alongside prayers and speeches.
Dr Rowan Williams told Premier: "To be truly responsible, both to the world we're in, the world God has given us and to the neighbours God has given us near and far, we really need to get a deeper sense of urgency about the climate crisis.
"We can pray for our leaders, we can pray that the sense of urgency will deepen for them. We can pray for the whole of our society for a readiness to see what we can give up and what we can do without for the sake of all our neighbours."
Christians from across the denominational spectrum will come together so that day or night, someone is praying for urgent action on climate change and for those in poor countries who have not caused the crisis to be protected.
It is being led by Christian Aid with support from fellow charities Cafod and Tearfund, plus the Lutheran World Federation, the Church of Sweden, the World Council of Churches and many others.
Organisers are also hoping that time will be set aside during this summer's Lambeth Conference for attending Anglican bishops to take part.
A website has been set up so that individuals can book slots and log their prayer time, with churches, small groups, individuals and families encouraged to join in.
Christian Aid's CEO Amanda Khozi Mukawashi said: "It's going to require divine intervention. At least that is what I believe as a person of faith that on our own, we will not be able to drive this.
"That's why we've come together. That's why we agreed, we looked at ourselves and said; while we are demanding and asking for actions, whether it's net zero, whether it's stopping the investment in fossil fuels, whether it's stopping the exploitation of indigenous communities, we need to accompany it with prayer.
"Let's pray together. Let's take action, and let's ensure that when the UK Government hosts COP26 in Glasgow let's make sure our politicians are doing their bit, to make sure the ambition is the right level of ambition that is going to require us to change our habits, our behaviours, our policies and our investments."