40%: The increase in atmospheric carbon dioxide (CO₂) levels since the start of the industrial revolution.

26%: The increase in ocean acidity from preindustrial levels to today.

about 170%: The projected increase in ocean acidity by 2100 compared with preindustrial levels if high CO₂ emissions continue (RCP* 8.5).

10 times: The current rate of acidification is over 10 times faster than any time in the last 55 million years.

24 million: The number of tonnes of CO₂ the ocean absorbs every day.

[This text is from the Ocean Acidification Summary for Policy Makers, 2013, and is available online as a PDF with full references.]