This column appeared at CatholicPhilly on 19 June 2015.
Let us sing as we go. May our struggles and our concern for this planet never take away the joy of our hope. — Pope Francis, Laudato Si’ 
This morning I read Laudato Si’, Pope Francis’ encyclical letter on caring for our common home, the Earth. All 40,000 and some odd words of it. It was a difficult read at times. Not because I lack the necessary background to appreciate either the science or the theology — I have a Ph.D. in chemistry, did some of my graduate research on atmospheric chemistry with Sherry Rowland, who won the Nobel prize for his work on ozone depletion, and have completed many hours of graduate theology course work — but because it brought into such sharp focus the challenges my most vulnerable brothers and sisters face and my role in them. In his letter, Pope Francis invites us to “become painfully aware, to dare to turn what is happening to the world into our own personal suffering and thus to discover what each of us can do about it.” 
Pope Francis begins by sketching out some of the most pressing and troubling difficulties facing creation: pollution, a culture of waste, climate change, reduced biodiversity and the need for clean water. As I read, I could hear the canticle of the three young men from Daniel whispering below the surface: “All you winds, bless the Lord … fire and heat, bless the Lord … all you beasts, wild and tame, bless the Lord!”
All of creation calls out the name of God, I am reminded, as I listen to the ways in which humankind has stilled some of the voices in that chorus, “making our earth less rich and beautiful, ever more limited and grey.” 
Coming so soon after the Easter season, where each week my parish began Mass by blessing water and sprinkling the congregation, I am struck by the pope’s attention to water. Water was created, we hear in the words of blessing, “to make the fields fruitful and to refresh and cleanse our bodies. You also made water the instrument of your mercy.”
Water is such a potent symbol of salvation. We are immersed in it at our baptism. We mingle it into the wine that will become our very life. Yet Pope Francis reminds us that most of our poorest brothers and sisters live where the water brings not life, but disease and death. Drought plagues farmers whose crops fail and whose land is mercilessly scoured away by the wind.
We must act boldly, the pope says, for the sake of “the sufferings of the crucified poor and for the creatures of this world laid waste by human power” . While much of the work must be done as communities and nations, each of us, he says, can follow the example of St. Therese of Lisieux and undertake simple acts with love.  Such actions “call forth a goodness which, albeit unseen, inevitably tends to spread.” 
Recycle and reuse what you can. Don’t waste food. Turn off the air conditioning. Say grace before meals. Keep the sabbath. Celebrate the Eucharist. Simple daily gestures that break us of the habits of selfishness, and push back against a throw-away culture.
Despite the headlines that say, “Pope aligns himself with mainstream science on climate change,” at its heart this letter is not about whether we should be for or against climate change; the science is, in fact, quite settled.
This teaching document demands all of us recognize the particular vulnerability of the poor to ecological damage and open our hearts and our minds to see how we might treat our common home so that all, but most of all the poor, might live with dignity.
Let us sing and praise the Lord, as we go. Laudato si’, mi’ Signore!