There’s substantial evidence that the earth is undergoing major adjustments as a result of human-made carbon emissions in the atmosphere, but what does climate change really mean? NASA climate scientist Gavin Schmidt and photographer Joshua Wolfe, editors of Climate Change: Picturing the Science, explain how scientists gather evidence and information about how the earth’s climate is changing—measuring air and ocean temperatures, water levels, glaciers and polar ice caps, and tracking storms—and how that data is interpreted.