On 28 April, the Secretary-General met with His Holiness Pope Francis at the Vatican and later addressed senior religious leaders, along with the Presidents of Italy and Ecuador, Nobel laureates and leading scientists on climate change and sustainable development.

Amidst an unusually heavy rainstorm in Rome, participants at the historic meeting gathered within the ancient Vatican compound to discuss what the Secretary-General has called the “defining challenge of our time.”

The mere fact that a meeting took place between the religious and scientific communities on climate change was itself newsworthy. That it took place at the Vatican, was hosted by the Pontifical Academy of Sciences, and featured the Secretary-General as the keynote speaker was all the more striking.

This summer, Pope Francis is expected to issue a papal encyclical, one of the Catholic Church’s highest teachings, on humanity’s relationship to the environment. This will be the first-ever papal encyclical devoted to the environment, and climate change is expected to be included within the context of broader sustainable development objectives.

The 28 April event was seen by many as the precursor to the release of the papal encyclical, which will come just months before the UN climate conference in Paris, where governments will gather to forge a collective response to climate change. That response, said the Secretary-General, must be “universal, fair and ambitious”.

Over the last two years, Pope Francis has spoken out strongly on the need to take action on climate change to protect the poorest, most vulnerable populations, as well as to protect the Earth for future generations.

In his remarks at the Vatican, the Secretary-General applauded the Pope’s leadership on these issues and said he shares the Pontiff’s view that climate change is not just an economic or scientific issue. It is, he said, also a moral issue, one with profound consequences for social justice, human rights and inter-generational equity. In this vein, according to the Secretary-General, the voices, deeds, and teachings of the world’s faith groups are vitally important.

The Secretary-General’s message was clear: science and religion are not at odds on climate change. Indeed, he noted, they are fully aligned. Both are calling for urgent collective action to mitigate the risks of increasing climate impacts. As the Secretary-General said in his keynote speech, science tells us that climate change is occurring, and that human activities are the principal cause. But it is our values, he said, be they religious or secular, which propel our response to the science.

Cardinal Peter Turkson, the Ghanaian President of the Pontifical Council for Justice and Peace, told the gathering that from a faith perspective, there is an “all-embracing moral imperative: to protect and care for both creation, our garden home, and the human person who dwells herein — and to take action to achieve this.”

The Secretary-General noted that as a secular organization, the United Nations has no common religion. But, he said, like all the major faiths, it too works on behalf of the disadvantaged and the vulnerable and shares the same ethical foundation: a belief in the inherent dignity of all individuals.

Protecting the poor, ending extreme poverty, ending social exclusion of the weak and marginalized, and protecting the environment are values that are fully consistent with the teachings of the great religions, he said.

The United Nations, he said, works in partnership with governments, the private sector, civil society and faith-based groups to create transformational change that upholds these values.

The Secretary-General, along with several other speakers, stressed that caring for the poor and most vulnerable must be foremost in leaders’ thoughts this year. Governments meet in September to adopt a new, post-2015 framework for sustainable development, and in December in Paris to forge a global response to climate change.

The Secretary-General will welcome Pope Francis to the UN in September where he will address the General Assembly.

This year, he added, the world has the opportunity to create a future in which we are good stewards of our common home and good neighbors to all.