The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.

The world's ocean has already experienced a 30% rise in acidity since the industrial revolution, with acidity expected to rise 100 to 150% over preindustrial levels by the end of this century. Potential consequences to marine life and also to economic activities that depend on a healthy marine ecosystem are difficult to assess and predict, but potentially devastating. To address this knowledge gap, Congress passed the Federal Ocean Acidification Research and Monitoring (FOARAM) Act in 2009, which, among other things, required that an interagency working group create a "Strategic Plan for Federal Research and Monitoring of Ocean Acidification." Review of the Federal Ocean Acidification Research and Monitoring Plan reviews the strategic plan on the basis of how well it fulfills program elements laid out in the FOARAM Act and follows the advice provided to the working group in the NRC's 2010 report, Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean. This report concludes that, overall, the plan is strong and provides a comprehensive framework for improving our understanding of ocean acidification. Potential improvements include a better defined strategy for implementing program goals, stronger integration of the seven broad scientific themes laid out in the FOARAM Act, and better mechanisms for coordination among federal agencies and with other U.S. and international efforts to address ocean acidification.