Why All Christians Should Heed Pope Francis’ Call to “Care for Our Common Home”


For more than a century now, arguments over science and faith have been dominated by origins. Today, though, another issue has become prominent. Climate change—specifically, the issue of whether human emissions of carbon dioxide and other heat-trapping gases are altering the planet’s climate—is an important topic at the intersection of science and faith.

As of the last midterm elections, climate change was the most politically polarized issue in the United States. It didn’t just trump other scientific issues: it beat out immigration, gun control, and even abortion on where Republicans and Democrats are most divided.

Make no mistake: the political divide is real, and runs deep. Climate change is a tragedy of the commons, which means that individual actions, while essential, will never achieve a sufficient solution. Collective action is required, and collective action typically implies government policy. For many, anything that smacks of government interference is anathema. And it’s true—policy choices are, and should be, highly political. The reality of the science, however, should not be.

What does this have to do with our faith?

Opponents of the reality and severity of human-induced climate change often link their skepticism to their faith. “The climate of the globe has been fluctuating since God created it,” or “our climate will continue to change because of the way God formed the earth,” and “man will not destroy this earth,” politicians tell us. Similar messages echo through the media, and even filter down to our pulpits, Catholic and Protestant alike.

At the same time, increasing numbers of Christian leaders are speaking out forcefully regarding the moral imperative to act. This week, Pope Francis released an encyclical—a formal document with a very significant weight of authority meant usually to define the boundaries of the debate —on climate change and the environment. The encyclical is titled “Laudato Si’,” which means “Praise Be to You,” and is subtitled “On the care for our common home.”

The Pope is not alone; the 2006 Evangelical Climate Initiative, the 2011 National Association of Evangelicals report, “Loving the Least of These,” and the 2013 letter from 200 evangelical scientists to Congress all state in clear and unmistakable terms that the basis for caring about climate change is nothing less than love—a fundamental Christian value espoused by any believer from any denomination.

So whom should we believe? As scientists, we know the importance of evidence; whether revealed through God’s written word or through creation. There is nothing in the Bible that says human-induced climate change isn’t possible. And there is plenty in creation that tells us that it is.

The idea that humans can disrupt the natural carbon cycle and alter the climate through digging massive amounts of coal, oil, and gas out of the ground and burning them is based on simple concepts in radiative transfer and physical chemistry that have been well established for over 150 years. French scientist Joseph Fourier was the first to identify the natural blanket of heat-trapping gases that wraps our planet, keeping it nearly 30oC or 60oF warmer than a black body would be. The Irish chemist Tyndall demonstrated how human activities – specifically coal mining – were releasing gases that artificially thickened this blanket. Swedish chemist Arrhenius built the first climate model in 1890. After two years of hand calculations, his estimates of how much the world would warm if carbon dioxide levels doubled or tripled due to fossil fuel use were remarkably close to what our most powerful supercomputers tell us today.1 The long history of climate science is the foundation for today’s consensus: over 97% of climate scientists and over 99% of the climate science literature agrees that the more carbon we burn, the thicker our atmosphere’s blanket of heat-trapping gases becomes, and the more the planet warms.2

For each of us as individuals, though, the last symptom we’ll notice is global warming. What we’ll notice are the other, more local symptoms of climate change: warmer winters, increasing risk of heat waves and heavy precipitation, stronger hurricanes and droughts, and many other aspects of local climate described in detail in the U.S. National Climate Assessment. Of course, natural weather patterns continue to affect us from day to day and year to year; but over climate timescales (the average of 20-30 years), the planet is warming and our weather patterns are changing. Because emitted carbon dioxide remains in the atmosphere for decades to a century, future generations will experience even more intense changes than we already do today.3

Why do we care about climate change? For a long time, the face of climate change has been the polar bear – or Al Gore. As scientists who study the impacts of climate change every day, though, this is not why we—Katharine and Ed—care about climate change. For us, the face of climate change is the California farmer, wondering where his water will come from for this year’s crops; the Bangladeshi refugee, whose land was flooded by sea level rise and has no where to go and no way to support her family; or the Alaska Native whose entire community has become uninhabitable due to thawing permafrost and melting sea ice. And this relates directly to our faith.

No matter what Christian denomination we come from (Ed attends a Catholic church, Katharine a nondenominational Protestant one), we all agree on the greatest commandments: love God and love others, especially the marginalized and vulnerable, as ourselves (Matthew 25:37-40). The apostle Paul takes it even further: walk in love as Christ loved us (Ephesians 5:2), with a sacrificial love that considers others not just on par, but above ourselves. Today, with our neighbors here at home and on the other side of the world feeling the impacts from climate change, our faith speaks directly to the need to acknowledge the reality of this issue and to do something about it.

This is why the Pope’s unprecedented encyclical on climate change matters so much. It makes a moral call for action based on the fundamental premises of the Christian faith – premises so fundamental that we can all, and must all, agree.

The encyclical emphasizes the need for transformation on a personal and societal level. As summarized by the Pontifical Academy of Sciences in its recent document Climate Change and the Common Good, during the 20th and 21st century the “three billion poorest people continue to have only a minimal role in the global warming [carbon] pollution, yet are certain to suffer the worst consequences of unabated climate change.”

What are the responses the encyclical proposes? First and foremost, all nations must focus on a rapid transition to renewable energy sources, and prepare the most vulnerable people to adapt to inevitable changes while meeting their energy needs sustainably. The encyclical recognizes that we must find ways to protect and conserve the living fabric of the world on which we depend. This demands a reorientation of our relationship with our environment and each other.

As summarized by Cardinal Turkson in his recent address at the Vatican summit “Protect the Earth, Dignify Humanity,” the solutions cannot be merely technical, but must be grounded in morality and measured by human well-being.  The encyclical recognizes the need for innovative technological solutions, such as energy storage and energy efficiency of buildings. More broadly than this, however, our response must “integrate questions of justice … so as to hear both the cry of the earth and the cry of the poor.” We need political leadership to guide us as we redirect our technological and economic systems from a single-minded “view to profit” to work toward a future that is “healthier, more human, more social, more integral.” Bound up with solving the climate crisis is a need for “healing all fundamental human relationships.” One way this should be expressed is with developed countries not only  reducing their non-renewable energy consumption, but “assisting poorer countries to support policies and programmes of sustainable development.” The responses posed in the encyclical can be intimidating, including a conversion of hearts and minds, habits and lifestyles, structures and institutions. At the same time this is hopeful, calling us toward reshaping our relationships, with each other and the environment, to reflect the deep compassion that is at the core of our faith.

As scientists and Christians, what does this mean? In this world, there is only really one thing we Christians are called to do: to fearlessly express Christ’s love to others. In the case of climate change, how do we express this love? Through acknowledging the reality of the issue; supporting action to help others who are being harmed now, today, and in the future; and taking our responsibility to care for God’s creation seriously.


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