This week marks the first anniversary of the call by Pope Francis to the world’s 1.2 billion Catholics to join the fight against climate change, which was pivotal in building momentum for the historic Paris Climate Change Agreement and for sustainable development.

In a papal encyclical letter called "Laudato Si" ("Praised Be") Pope Francis declared that the science of climate change is clear and that the Catholic Church views climate change as a moral issue that must be addressed in order to protect the Earth and everyone on it.

The encyclical was part of a wider mobilization by faith groups around the world to achieve both the Paris Agreement in December 2015 and agreement on new sustainable development goals earlier in the year.

Christiana Figueres, Executive Secretary of the UN Framework Convention on Climate Change, said

“The Pope’s encyclical, along with mobilization by many other faith groups across the globe, provided a clear moral imperative for taking climate action, supporting the Paris Climate Change Agreement and backing the 17 Sustainable Development Goals. One year on, faith groups need to continue their valuable work so as to ensure that words are turned into action, at the speed and scale required to lift the world’s most vulnerable populations out of poverty, in order to catalyze sustainable development and to realize the Paris Agreement’s vision of a climate safe world.”

According to the National Catholic Reporter, Pope Francis’encyclical has had visible impact over the past year in addition to helping to move forward the international climate and sustainable development agendas.

Many parishes, schools and communities have studied, reflected and discussed the text, often through multidisciplinary conferences. Other church members have begun taking first-step actions at institutional levels by forming green teams, improving energy efficiency and reducing wasteful consumption.

Laudato Si has also played a role in motivating Christian churches and other faith groups to disinvest from polluting fossil fuels and to invest in cleaner forms of energy. The week of the anniversary of Laudato Si, four Australian Catholic organisations have announced they are completely divesting from coal, oil and gas in what they say is the first joint Catholic divestment anywhere in the world.

The move comes as prominent Jewish rabbis, Muslim clerics, Anglican bishops and other religious leaders call on the Australian government to protect the Great Barrier Reef, stop approving coalmines and remove subsidies to the fossil fuel industry, in an open letter published by the Guardian.