Tom Harris, executive director of the Ottawa, Canada-based International Climate Science Coalition: In a recent interview with the Vatican News service, former U.S. Vice President Al Gore again claimed “the climate crisis is now the biggest existential challenge humanity has ever faced.” The Goddard Institute for Space Studies asserts that the Global Annual Mean Surface Air Temperature Change from 1880 to 2017 is only just over one degree Celsius despite a reputed 40% rise in atmospheric carbon dioxide (CO2) content.