March 31 (UPI) -- Greta Thunberg will publish a book this fall, the 19-year-old Swedish environmental activist confirmed on Thursday. The Climate Book will be published in October by Penguin Press, and will have several contributing authors. "I've invited over 100 leading voices from around the world -scientists, experts, activists and authors to create a book that covers the climate- and ecological crisis from a holistic perspective," Thunberg said on Twitter. Leading scientists and Canadian novelist Margaret Atwood are among those contributing the book, that Thunberg hopes will become "an essential tool" in the fight against climate change. The book's...