Several dozens of mayors from major cities across the world gathered in Vatican to discuss the link between slavery and climate change. The Vatican conference of last week clearly showed how secular leaders from across the world are responding to the lead taken by Pope Francis to protect the environment.

Majorly the conference aimed to discuss the necessary steps that could be taken in cities to combat climate change. The mayors who attended the conference pledge to lobby their governments to work for a binding climate treaty this fall in Paris at the UN-sponsored climate change talks.

New York City, San Francisco, New Orleans, Boston, Madrid and Rome were among the cities whose mayors attended the Vatican conference of last week with Pope Francis.

Apart from his long climate change and social justice encyclical earlier this spring Pope Francis also signed a declaration stating that climate change due to human activities is a scientific reality and its effective control is a morally necessary for humanity.

New York City Mayor Bill de Blasio, one of the attendees of the conference during his speech said, “It's increasingly clear that we local leaders of the world have many tools and that we must use them boldly even as our national governments hesitate”.

California Governor Jerry Brown who was also present for the conference said in a statement that the hope is that local government leaders can create pressure on the national leaders.

Pope continued to link the fight against climate change to issues of social justice. He is also planning to sponsor more conferences on climate change in the lead-up to the Paris negotiations.