In 2009, climate scientist Dr. James Hansen published his first book, “Storms of My Grandchildren,” on the topic of climate science and his involvement in various governmental efforts over the previous two decades to craft a response to what he described as “the greatest threat civilization faces.” Dr. Hansen is perhaps the world’s most prominent climate scientist. Trained as an atmospheric physicist, he worked at NASA’s Goddard Institute for Space Studies for 45 years, and was its head from 1981 until his retirement in 2013. He is known for his groundbreaking body of work, and for his outspoken warnings regarding the possibility of “tipping points” being reached in the climate system that could lead to runaway global warming.