Fresh off his success in helping to end one of the last remaining battles of the Cold War, Pope Francis is turning his attention – and bringing his considerable star power – to the fight against global warming.

His decision to push for an international treaty on climate change in Paris in December may alienate some conservative Catholics who are skeptical of climate science. But Francis’ leadership on the issue is a hopeful sign that 2015 could be the year that the nations of the world finally commit themselves to collective action.

The pope’s new focus on climate change is a natural outgrowth of his concern for the poor, who will suffer most if droughts and storms worsen, allowing disease and instability to spread more easily. Both John Paul II and Benedict XVI sounded the alarm on climate change, and in 2011 the Vatican’s Academy of Sciences issued a report that called on “all people and nations to recognize the serious and potentially irreversible impacts of global warming” caused by human activity. Francis is not changing church teaching, only seizing the moment, as a public consensus emerges around the need for coordinated action.

In March, he’s expected to visit Tacloban, the Philippine city hardest hit by last year’s typhoon Haiyan, which killed thousands and left millions homeless. As the planet warms and the seas rise, severe storms are expected to become even more destructive.

This trip may be followed by a papal encyclical on climate change, a letter to the bishops that will formalize the church’s position on the issue and guide its ministry at the parish level. In September, Francis will have a chance to raise the issue when he addresses the U.N. General Assembly. He may also convene a summit of religious leaders to focus attention on climate change, which has generated widespread ecumenical agreement.

All these steps will occur in the run-up to the U.N. summit on climate change in Paris at the end of this year. Francis is throwing the weight of the church – and his papacy – behind an international agreement.

There are many obstacles between here and there. But Francis and other religious leaders can play a constructive role by pushing leaders in the developing world to adopt ambitious goals – and those in the developed world to offer the financial support needed to achieve them.