To follow the world's headlines these days - from fake news to murderous terror attacks, from disease pandemics to global warming - you might be forgiven for thinking the world is becoming a pretty scary place. But is it really? Harvard University cognitive psychologist and author Steven Pinker tells us that is measurably not the case. As he argues in his new book Enlightenment Now, we are in a golden age of human existence. But, David Edmonds meets academics who are putting Pinker's ideas to the test, concluding that with climate change and overpopulation, there is a 10% chance of humans not surviving the 21st Century. (Photo: Activist at a climate change protest in Spain. Credit: Getty Images)