Over the weekend, The Guardian reported that Pope Francis will issue an encyclical urging Catholics to push for action on climate change. The push will coincide with the efforts to follow up on the Lima agreement in the hope that they will lead to binding agreements for the reduction of greenhouse gas emissions.

Although the Vatican has not confirmed that the document is in the works, the article quotes several authorities by name, and they speak as if it is a done deal. The document would be in keeping with the Pope's messages on environmental stewardship; the article quotes Francis as telling an audience in Latin America, "Climate change, the loss of biodiversity and deforestation are already showing their devastating effects in the great cataclysms we witness.” It's also consistent with his general high regard for scientific findings.

The Pope will join a variety of voices pushing for action next year and will undoubtedly add to the political pressure for an agreement. A more relevant question may be whether Francis can sway anyone who wasn't already interested in seeing progress made on the climate.

For example, The Guardian notes that Cardinal George Pell, who is currently on staff at the Vatican, has frequently and publicly questioned our scientific understanding of climate. In a speech he gave to a UK think tank that questions the reality of anthropogenic climate change, he raised many of the tired, already-answered arguments that are features of the self-labelled "skeptic" community. (He also quotes some of the least reliable sources of climate information out there.)

There's also little indication that many Catholics actually follow their leadership on scientific matters. The church hierarchy has been nearly unanimous in its acceptance of evolution for decades, yet over a quarter of US Catholics continue to reject it.

And it's already clear that the Pope's message will be lost on non-Catholics. The Guardian quotes a representative of a US evangelical group as saying "The pope should back off" and the Vatican "has been misled on the science." That group, the Cornwall Alliance, is about as well-informed as Cardinal Pell, given that its statement on climate change contains things like "We deny that carbon dioxide—essential to all plant growth—is a pollutant."

The Cornwall Alliance's statement also makes clear that the issues it sees are as much economic as ethical. It argues that action on climate "will greatly increase the price of energy and harm economies," and that renewable energy would fail, "to provide the abundant, affordable energy necessary to sustain prosperous economies or overcome poverty."

Given the Pope's messages on environmental stewardship have tended to come wrapped in the language of social justice and questions about the ethics of laissez-faire capitalism, they're more likely to harden this opposition than convert it.

None of this is to say that the encyclical is irrelevant. The Pope could add a significant push to the building momentum for a climate agreement and may be able to sway undecided Catholics. But it's doubtful that Francis' public statements will sway the hardened opposition.