On a sprawling, multicultural, fractious planet, no person can be heard by everyone. But Pope Francis comes closer than anyone else. He heads the world’s largest religious denomination and so has 1.2 billion people in his flock, but even (maybe especially) outside the precincts of Catholicism his talent for the telling gesture has earned him the respect and affection of huge numbers of people. From his seat in Rome he addresses the developed world, much of which descended from the Christendom he represents; but from his Argentine roots he speaks to the developing world, and with firsthand knowledge of the poverty that is the fate of most on our planet.

So no one could have considered more usefully the first truly planetary question we’ve ever faced: the rapid heating of the earth from the consumption of fossil fuels. Scientists have done a remarkable job of getting the climate message out, reaching a workable consensus on the problem in relatively short order. But national political leaders, beholden to the fossil fuel industry, have been timid at best—Barack Obama, for instance, barely mentioned the question during the 2012 election campaign. Since Francis first announced plans for an encyclical on climate change, many have eagerly awaited his words.

And on those narrow grounds, Laudato Si’ does not disappoint. It does indeed accomplish all the things that the extensive news coverage highlighted: insist that climate change is the fault of man; call for rapid conversion of our economies from coal, oil, and gas to renewable energy; and remind us that the first victims of the environmental crisis are the poor. (It also does Americans the service of putting climate-denier politicians—a fairly rare species in the rest of the world—in a difficult place. Jeb Bush, for example, was reduced to saying that in the case of climate the pope should butt out, leaving the issue to politicians. “I think religion ought to be about making us better as people,” he said, in words that may come back to haunt him.)

The pope’s contribution to the climate debate builds on the words of his predecessors—in the first few pages he quotes from John XXIII, Paul VI, John Paul II, and Benedict XVI—but clearly for those prelates ecological questions were secondary. He also cites the pathbreaking work of Bartholomew, the Orthodox leader sometimes called the “green patriarch”; others, from the Dalai Lama to Anglican archbishop Desmond Tutu, have spoken eloquently on this issue as well. Still, Francis’s words fall as a rock in this pond, not a pebble; they help greatly to consolidate the current momentum toward some kind of agreement at the global climate conference in Paris in December. He has, in effect, said that all people of good conscience need to do as he has done and give the question…