For decades, scientists at Exxon knew the Earth's climate was warming, and the oil giant made business decisions based on their predictions. But in 1990, the company began funding deniers of climate science, and their reports persuaded policy makers to resist limits on the burning of fossil fuels. Now, Exxon's accused of deliberate deception for profit — leaving the world less prepared than it might have been for oncoming disaster. Democrats and activists want an investigation of fraud — but there's a problem. The records are an open book. Exxon never kept anything secret.