"The annual rise of 17 billion tons [of atmospheric carbon] translates into a rising concentration of carbon dioxide in the atmosphere. Each additional 7.8 billion tons is equivalent to one part per million in the atmosphere, so that an extra 17 tons each year is equivalent to a rise of roughly two parts per million."
- Common Wealth, p. 92, Jeffrey D. Sachs
Hint: The word "billion" is missing in one place.
Hint: If the amount of carbon dioxide needed to add 2ppm is what he wrote, then the earth would have become a desert already.
The moral: Once you proofread something you wrote, proofread it again. I caught at least one in what I typed above!
