Two decades ago, Al Gore's movie An Inconvenient Truth thrust climate change into the global spotlight. With dramatic imagery and dire warnings, it transformed a niche concern into a front-page crisis, influencing rich country leaders and elite jet-setters, and inspiring a generation of activists. Twenty years affords distance to reflect not just on the film's impact but also its accuracy. Many of Gore's most alarming predictions have failed to materialize, while the policy response it helped inspire has proven extraordinarily flawed.