Faith leaders made a strong showing in Copenhagen over the weekend, giving their final efforts towards lobbying delegates at the UN climate change conference to seal a legally binding agreement that will combat the effects of climate change.

On Saturday the Archbishop of Canterbury Rowan Williams gave encouragement to a crowd of nearly 100,000 gathered to participate in a march to press for a climate deal, calling the demonstration "the most important event that we're likely to see in our life time."

"Why is it important? It's important because you are going to try to help our leaders lead in the world," Williams said.

"We have to make it the case that the people of our world are demanding justice in such a way that it's impossible for our political leaders to deny it. That's why we're all here in Copenhagen. That's what you're marching for," he continued.

Williams gave similar remarks on Sunday during a speech at the Copenhagen Cathedral, calling believers everywhere to choose love over fear when making decisions to act on influencing climate policy.

"We meet as people of faith in the context of this critical moment in human history [to say] do not be afraid", Williams said. As "love casts out fear", it also helps to take "the right decisions for our global future".

Broadcast live on Danish television, William's speech was a part of a special ecumenical celebration involving various faith leaders, COP15 delegates and Queen Margrethe II of Denmark.

At the end of the celebration was a bell ringing at the cathedral – an event participated in by thousands of churches across the globe who rang their bells 350 times to symbolize the 350 parts per million that, according to many scientists, is the safe upper limit for CO2 in the atmosphere.

Prominent participants in the bell ringing included the Netherlands where over 900 congregations signed up for the campaign and Switzerland, where 550 congregations participated.

In other globalized efforts, a compilation of over half a million signatures for climate justice were handed over to Executive Secretary of the UN Framework Convention on Climate Change Yvo de Boer on Sunday morning as a part of the Countdown to Co2penhagen campaign.

Archbishop Emeritus Desmond Tutu presented the signatures to Boer, saying to the crowd, "We say no to the injustice of Climate Changes, causing poor people to suffer from something, they did not cause themselves."

In receiving the campaign's clock, Boer said that despite the financial crisis and other obstacles, "it is a moral crisis that is standing in the way of us addressing an environmental crisis".

"Let your voices be heard", the UN official said, "because Copenhagen is the one chance we have to get this right".