I am very concerned about climate change. Historically climate change has almost always resulted in significant social pressure as well as ecological changes. We could shortly be on the edge of such a climate change event. That said We face an incredible array of challenges such as pollution of our air oceans and lands, deforestation, food production restraints, limited resources, technological changes, severe overpopulation especially in many third world developing countries and not even to mention humans greatest harmful affliction, warfare.
All that said, I think that the greatest challenge we face is non of these. I think our greatest challenge we face as a species is understanding God’s purpose for our lives and the spiritual emptiness that pervades our species. The materialistic society that pervades our planet is spiritually empty and will never lead to fulfillment.