Randall Munroe once again shows that he's one of the web's most talented storytellers, inventing ways of conveying information that use the web's affordances to novel and sharp effect (there's a reason he won a Hugo award).
This time, he's tackling climate change, with a long, vertically scrolling timeline of planetary temperature from 20,000 BCE to various projects in 2100. What starts as a leisurely tour through history literally veers into alarming territory in the last few pixels. It's the contrast that makes this work so well.
Earth Temperature Timeline