Simply put, climate change is caused by excessive production of greenhouse gases. As highlighted by the late Professor Tony McMichael, the “cause(s) of the causes” should not be overlooked.1 With climate change already close to an irreversible tipping point, urgent action is needed to reduce not only our mean (carbon) footprints but also the “number of feet”—that is, the growing population either already creating large footprints or aspiring to do so.