By now, almost everyone on the planet views CC as real and sees human activity as the main cause. There is ever-mounting evidence that its cascading impacts will prove to be one of the greatest crises ever to face humanity. There is a panoply of serious impacts already unfolding: sea level rise and the dislocation of coastal residents and physical assets; the exponential increase in climate refugees; more air pollution, from particulate matter to ozone; loss of biodiversity and habitat for other plant and animal species on which humans rely; acidification of the oceans and loss of life-filled coral reefs; economic disruption and institutional instability; and breakdowns in social norms and civic culture. The urban heat island effect (UHIE) is the full technical term, coined in the 1940s, to describe the higher air and surface temperatures in cities compared to their hinterland. The third big challenge is global population explosion, which puts onerous demands on our finite supply of natural resources and pumps more pollutants into the atmosphere and water. The environmental and population paradoxes of cities are explained as two of the major benefits of urbanism in the war on climate change.