We are here in Panama,” stated Naderev Sano, “to tell the world that climate change is a matter of life and death for the Philippines.” Sano is commissioner of the Filipino Climate Change Comission, and he spoke these words at a meeting held in preparation for the UN meeting on climate change,  which opened in Durban, South Africa on November 28. Although Catholics may not usually think of climate stabilization as a pro-life issue, it is increasingly clear that protecting the sanctity of life means not only working to end abortion and the death penalty but also acting to conserve the earth’s climate and biosphere.
The world’s most prestigious scientific bodies are in agreement that global warming is a reality caused primarily by human beings and that its consequences on our economy and environment will be far-reaching. In the short term, climate change will bring an increase in extreme weather events that threaten human populations and agricultural production. In the long term, the very viability of human civilization is at stake.
The climate is changing because of the “greenhouse effect,” a phenomenon by which heat-trapping gases in the atmosphere retain the infrared radiation reflected when the sun’s rays touch the earth’s surface. Were it not for some level of atmospheric greenhouse gas, the planet would be too cold to support life as we know it. But our combustion of fossil fuels, our razing of forests and our agricultural practices have elevated the atmospheric concentrations of the greenhouse gases carbon dioxide, methane and nitrous oxide. Prior to the industrial revolution, atmospheric carbon dioxide was 280 parts per million (ppm). Today it is 391 ppm and rising by about 2 ppm each year. Between 1900 and 2009, the global average surface temperature rose 1.3 degrees Fahrenheit.
This may sound negligible. But the global climate is a very complex reality in which a small change in average temperature has ripple effects on ocean currents, precipitation patterns and other climate systems. An apparently small temperature increase is already destabilizing the energy balance of the climate and spawning changes adverse to human beings and other species. Impacts can be seen in many areas, including the following:
Agriculture. Plants are very sensitive to changes in temperature and precipitation patterns. Between 1980 and 2008, rising temperatures reduced total global wheat production by 5.5 percent. According to a study published by the U.S. National Academy of Sciences, every 1.8 degree Fahrenheit rise in average temperature will reduce the global yields of wheat, rice and corn by an additional 10 percent. Some regions will be affected more severely than others. Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC), projects  that as early as 2020 grain yields in some African countries could be reduced by as much as 50 percent.
Water. Around the world, sources of the fresh water necessary for life are diminishing. Last May, a working group commissioned by the Pontifical Academy of Sciences published a report on the retreat of the world’s mountain glaciers. The water flowing gradually from these majestic ice formations sustains rivers that bring life to valley ecosystems and human communities. But the European Alps have already lost 50 percent of their glacial mass, and thousands of small glaciers in the Himalayan-Tibetan region are disintegrating . In Asia alone, over one billion people are in danger of losing their primary source of life-giving water.
Sea level rise. Melting glaciers and thermal expansion of ocean waters are contributing to a sea level rise already documented by scientists. According to one estimate, over the course of this century we can expect a rise of 3 to 6 feet. At just three feet, 50 percent of the rice fields in Bangladesh would be submerged. Portions of major coastal cities including New Orleans, Tampa and Miami would be inundated.
Ocean decline. The oceans absorb more than 25 percent of the carbon we emit through the combustion of fossil fuels—and in so doing they become more acidic. This is contributing to the decline of the coral reefs that provide habitat for a diverse array of exquisite sea creatures, including fish that are a source of protein for nearly one billion people. The warming of ocean waters has also been linked to a decline in the population of phytoplankton. These microscopic creatures produce oxygen, remove carbon dioxide from the atmosphere and form the base of the entire marine food web that supports krill, whales and fish.
Extreme weather events. There has been a marked increase in floods, droughts and other extreme weather events related to climate change. MIT scientist Kerry Emanuel , for example, has correlated rising sea surface temperature with an increase in the intensity and duration of hurricanes. Heat is a form of energy, and the warming of ocean waters increases the energy convection of storm systems.
Mass extinctions. Species already suffering from habitat loss in a world dominated by humanity may not be able to adapt to a rapidly changing climate. A report published in Nature in 2004 concluded that a climate warming in the mid-range of current projections will by the year 2050 lead to the extinction of 15-37 percent of the species examined in the study. Biodiversity is essential to ecosystem resilience. Moreover, as Thomas Aquinas noted, the rich diversity of earthly creatures gives humanity a glimpse of the beauty and glory of God.Tipping Toward Catastrophe
Those of us privileged to live in homes with central heating can quickly adjust our thermostat to raise or lower the temperature. One might imagine that at some future point, when global warming is more advanced, we can cease our greenhouse gas emissions and quickly return the planet to its prior state. The global climate, however, cannot be so easily moderated. The carbon dioxide we have already added to the atmosphere and oceans will impact the earth for at least 1,000 years. Moreover, the climate is not a simple mechanical system but a complex reality with many interlocking, non-linear relationships.
This complexity includes phenomena known by climate scientists as “positive- feedbacks”—processes that take a small change in temperature and amplify it with exponential effect. Consider, for example, the melting Arctic ice caps. These enormous white crests deflect solar radiation back into space, just as white clothing protects us from summer heat. As the ice caps melt dark sea water that absorbs solar warmth is exposed. This elevates the temperature of the ocean water, which increases the melting of the ice caps, which decreases the polar deflection of solar radiation, and on it goes.
This kind of feedback process is also evident in the decline of the world’s forests. Forests absorb carbon dioxide from the atmosphere and play an essential role in regulating global climate. Across the globe, forests are dying back. The underlying cause appears to be stress caused by rising temperatures and altered precipitation patterns. When trees die, they cease the photosynthesis that removes carbon from the atmosphere and as they decompose they release the carbon they have absorbed. This intensifies global warming, which increases the stress to forests, which kills more trees, which release more carbon, and so forth.
Thawing tundras are another example of “positive-feedback.” In Siberia, an enormous expanse of frozen tundra is beginning to thaw. The tundra holds an estimated 70 billion tons of carbon, much of which would be released as methane, a gas 25 times more powerful in its heat-trapping effect than carbon dioxide.
These positive-feedbacks are one reason that climate change is progressing more rapidly than projected by the Intergovernmental Panel on Climate Change . The rate of sea ice melt in the Arctic, for example, is thirty years ahead of a projection made by the IPCC in 2007. Using both current observable reality and data from paleoclimate studies, an international group of scientists has recommended carbon levels that could preserve a climate hospitable to life. Johan Rockström and coauthors conclude in “A Safe Operating Space for Humanity”  that a safe level of atmospheric carbon dioxide is no more than 350 ppm.
Atmospheric carbon dioxide is already at 391 ppm and rising 2 ppm each year. If we are to have at least a fighting chance of returning carbon dioxide levels to 350 ppm, the global community must work with unprecedented cooperation to transform our sprawling fossil-fuel global economy to a network of efficient regional economies powered by non-carbon sources of energy. We must preserve surviving forests and replant denuded lands; replace agricultural practices that release methane and carbon into the atmosphere with practices that restore soils and sequester carbon; and intensify research and development of other means of removing carbon from the atmosphere.
The urgency of the transition to a new form of human civilization cannot be overstated. The warming generated by our own greenhouse gas emissions and accelerated by nonlinear feedback processes is pushing us ever closer to what scientists call “runaway climate change.” This ultimately could elevate atmospheric greenhouse gases to the level of the Cenozoic Era (65 million years B.C.) when the planet was ice-free and homo sapiens did not exist. “We are interfering,” concludes science writer Fred Pearce, “with the fundamental processes that make Earth habitable.” A 2007-08 UN Human Development Report  concluded, “There is now overwhelming scientific evidence that the world is moving towards the point at which irreversible ecological catastrophe becomes unavoidable....There is a window of opportunity for avoiding the most damaging climate change impacts, but that window is closing.”Choose Life
Unlike abortion and the death penalty, climate change does not entail an intentional act that ends the life of another human being. It is the unintentional outcome of the industrial and agricultural processes that have accompanied our economic development. As early as 1979, however, scientists testified to Congress of the possible consequences of climate change, and our inaction is already taking the lives of vulnerable human beings. In 2009, a study conducted by the Global Humanitarian Forum  found that climate change was already responsible for 300,000 deaths a year, the suffering of 325 million people, and economic losses of over $100 billion. Over 90 percent of those persons most severely affected were from developing countries that have contributed least to global carbon emissions.
In the coming decades, climate change can bring deadly famine, displacement and disease to large sectors of the human population and spawn mass extinctions of other species. In the long term, the climate could change so radically that the earth could no longer support human civilization. In this sense, caring for the climate and the biosphere is a paramount pro-life issue.
Pope Benedict XVI lamented the failure of the international community to take appropriate action on climate change at the Copenhagen Climate Conference in 2009. The Vatican has installed solar panels on the roof of the Paul VI auditorium and declared the intention to make Vatican City the first carbon neutral state. In the United States, the Catholic Coalition on Climate Change supported by the bishops’ conference and other Catholic bodies is leading multiple initiatives, including the Catholic Climate Covenant . Participants in this covenant pledge in the spirit of St. Francis to educate themselves, pray, change their own energy-intensive patterns of living and lobby for policies that will address the climate crisis. These essential initiatives can be strengthened by recognizing climate change as a life issue that merits our attention in October’s annual Respect Life programs and January’s National Prayer Vigil for Life. We should also pursue new pro-life initiatives specific to the climate crisis, such as legal action to hold our government accountable for its repeated failure to protect the earth for generations unborn.
Our imperiled planet needs the distinctive paschal witness that the Catholic community can offer. At this time of ecological and economic crisis, Pope Benedict stated in a 2009 Easter address, "it is urgent to rediscover grounds for hope....Christ is looking for men and women who will help him to affirm his victory using his own weapons: the weapons of justice and truth, mercy, forgiveness and love."