"But to me, the most important thing Randall did in this comic is to beautifully show how rapidly the Earth is warming. The increase in temperature is pretty slow, with the dashed line of temperature moving left to right subtly as you scroll down. But then, finally, after nearly 15,000 pixels of scrolling down, you can see the temperature take a sudden sharp surge to the right, showing the painful and very recent upturn in heat stored all over our planet. It's a slap in the face."
Phil Plait at Slate praises Randall Munroe's illustrated timeline of climate change.