Now that Pope Francis has released his encyclical on climate change, strong responses from many climate change deniers has predictably emerged. Most of these attacks on the Pope’s message have focused on the Pope wandering from his area of authority in theology into science. Former Thatcher adviser Christopher Monckton’s retort is typical: “It is not the business of the Pope to stray from the field of faith and morals and wander in to the playground that is science”

The US media’s coverage, also predictably, has mostly focused on whether the Pope should have stayed in his theology lane.

Yet the most important potential message of the Pope’s encyclical is his assertion that climate change is a moral problem. Now, of course, many see the Pope’s claim about morality unsurprising but fail to understand the profound significance for climate policy-making of understanding climate change fundamentally as a moral issue. If climate  change is understood to be a moral issue, it would completely transform the way climate change policies have been debated in the United States for over three decades.

For instance, opponents of US government action on climate change have for over 30 years predominantly argued against proposed policies on two grounds. First there is too much scientific uncertainty to warrant action and secondly climate policies will destroy jobs, specific industries, and the US economy. For this reason, action on climate change is not in the US self-interest.

But if climate change is a moral issue, the United States may not look at US economic interests alone, it must respond to US duties and obligations to the tens of millions of people around the world who are  most vulnerable to climate change harms. Yet the US debate on climate change has made cost to the US economy of climate change policies, or economic impacts on specific US industries the key criteria for the acceptability of US action on climate change while ignoring what US ghg emissions were doing or threatening to do to tens of vulnerable people around the world.

In addition, if climate change is a moral problem, even assuming counter-factually that there is considerable scientific uncertainty about whether humans are causing serious global warming, those who are putting others at risk have duties to not endanger vulnerable people without their consent. This is particularly true on issues where waiting to resolve scientific uncertainty makes the problem worse or waiting makes the problem harder to solve, clear attributes of climate change.

It is the tens of millions of potential victims of climate change impacts that have the most to lose by waiting until all scientific uncertainties are resolved. Given that the mainstream scientific community now believes that the world is quickly running out of time to prevent dangerous climate change, the moral problems with waiting until all climate scientific uncertainties are resolved are unfortunately becoming obvious. The United States should have acknowledged the duty to fake action on climate change 30 years ago once the US Academy of Sciences and other highly respected scientific institutions stated that human-induced climate change was a growing menace.

Even without the Pope’s encyclical, Climate change is a problem with certain features that scream for attention to see it and respond to it as essentially a moral problem even more than other environmental problems. These features include the following:

• First, it is a problem that is being caused by some high-emitting people and nations in one part of the world who are putting other people and nations at great risk in another part of the world who have often done little to cause the problem.

• Second, the harms to those mostly at risk are not mere inconveniences, but potential catastrophic harms to life and natural resources on which all life depends.

• Third, climate change is a problem for which those people most at risk often can do little to protect themselves by petitioning their governments. Their best hope is that those high-emitting nations and people causing the problem will see that they have ethical duties to the victims to avoid harming them.

• Fourth, because CO2 is well mixed in the atmosphere, all human activities are contributing to rising atmospheric concentrations and therefore a global solution to climate change requires all nations and people to limit their greenhouse gas (GHG) emissions to their fair share of safe global emissions.

Because climate change is a moral problem, issues nations must face in formulating climate policies need to be guided by moral considerations. They include, among many others, principles on what is each nation’s fair share of safe global emissions, who is responsible for reasonable adaptation needs of those people at greatest risk from  climate damages in poor nations that have done little to cause climate change, should high-emitting nations help poor nations obtain climate friendly energy technologies, and what responsibilities should high-emitting nations have for refugees who must flee their country because climate change has made their nations uninhabitable?

Because climate change is a moral problem, high-emitting organizations, sub-national governments, corporations, and individuals also have duties to reduce their greenhouse gas emissions to their fair share of safe global emissions.

In the international climate negotiations that will resume on November 30 in Paris, issues of fairness are already the key issues in dispute. Hopefully the Pope’s encyclical will help citizens around the world see the moral dimensions of climate change policies and respond accordingly.

The US press has for 30 years utterly failed to help US citizens understand the practical significance for climate policy if climate change is a moral issue.  Perhaps the Pope’s encyclical will change this.