In 2007 Pope Benedict led the Catholic Church'sW first eco-friendly youth rally, with up to half a million people. He spoke of the need for "a strong commitment to reverse tendencies that risk leading to irreversible situations of degradation". "Courageous choices that can re-create a strong alliance between man and earth must be made before it is too late."
The Vatican Solar Array combined with a Hungarian reforestation projected turned the Vatican into the first carbon neutral state. In 2012, Benedict acquired an electric car after having earlier expressed interest in it.
For a detailed analysis of Catholic social thought as it relates to solar energy and environmental stewardship see: Joshua M. Pearce, Anna L. Santini, and Jennifer M. Desilva, "Solar Photovoltaic Energy for Mitigation of Climate Change: A Catalytic Application of Catholic Social Thought", Worldviews, Volume 13(1), pp. 92-118, 2009. open access