In the January 20 issue of Geophysical Research Letters, the most extensive survey of pH levels in the Pacific Ocean will confirm what spot measurements have recently suggested, namely that the upper reaches of the sea are becoming more acidic in concert with rising carbon dioxide (CO2) levels in the atmosphere. Robert Byrne, a marine chemist at the University of South Florida and lead author of the upcoming paper, collaborated with Seattle scientists on the survey, which was 15 years in the making. It is the first time measurements have been taken across such a wide area, said co-author Richard Feely of the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory in Seattle. “The fact that we saw this very significant change over the last 15 years is a reminder of how mankind is affecting the oceans at an ever-increasing rate,” Feely said. The study’s scientists calculated that since the start of the Industrial Age the acidity of the world’s oceans has increased 25 to 30 percent. Under a business as usual scenario, Feely said, ocean acidity could triple by the end of the century. Although extrapolating future rates of acidification is difficult because the ocean and atmosphere are so complex, and should thus be viewed cautiously, the authors argue that the trend of increasing acidification is clear.