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.]