IPCC Report Underscores Need to Address Ocean Acidification


In the recently released Fifth Assessment Report the Intergovernmental Panel on Climate Change documented more evidence that humans are causing climate change and expanded our understanding of the significance and speed of this change.

The report also addressed a second, independent impact of rising atmospheric CO2 emissions: ocean acidification. While national and international media outlets largely skipped any mention of the report’s findings on ocean acidification, as an ocean scientist my eyes went straight to the section on what we like to call climate change’s “evil twin.” This report marks a noteworthy milestone as the first time the IPCC has addressed in a thorough and meaningful way the science of how carbon dioxide pollution is changing ocean chemistry. The IPCC is currently the only international body reviewing and articulating the state of ocean acidification science, so this report is critical to reporting the current scientific consensus on this issue.

Ocean acidification is not just a concern for the future. On the west coast of the United States, where deeper, more acidified waters regularly upwell to the surface due to weather and currents, our country has felt the effects of ocean acidification earlier than in much of the globe. There, the Pacific Northwest oyster growing industry nearly collapsed before scientists were able to help devise strategies and monitoring to mitigate ocean acidification’s effects.

Yet while Northwest oyster hatcheries have been rescued for the present, new issues have surfaced elsewhere. Ocean acidification and warming waters are stressing coral reefs. Numerous other marine organisms are at risk. Many fishermen and shellfish growers from Alaska to Massachusetts are worried about where trouble might happen next.

The report’s news on ocean acidification is sobering, outlining clearly the process of chemical changes thus far and the expected changes in the future should we continue to pollute our air and water with excess CO2.

Some key information from the IPCC’s report:

  • There is solid evidence that our carbon emissions are changing the basic chemistry of oceans
  • Rising CO2 is causing other measurable changes in the ocean’s vital signs. The oceans are warming, and there have been changes in ocean oxygenation and salinity.
  • Estimates indicate that by the end of this century the average surface ocean pH could be lower than it has been for more than 50 million years.

If earlier scientific findings weren’t enough to stir action, this report should be taken as an immediate call for change. Fortunately, there are at least three major steps we can take to solve the ocean acidification problem:

  • The principal contributor to ocean acidification in much of the oceans is carbon pollution, so, first and foremost, we can slow changes to ocean chemistry by cutting carbon emissions. NRDC is hard at work on this issue. The largest source of those emissions in the United States is power plants, which is why we have pressed for limits on power plant carbon emissions. Last month, the U.S. Environmental Protection Agency issued the first-ever national carbon standards for new power plants, and in June President Obama directed the agency to do the same for existing power plants. NRDC will continue urging the administration to make the standards as strong as possible.
  • We also need to increase our monitoring of ocean chemistry. If we can figure out where ocean acidification is happening most rapidly, we can help those in the fishing and aquaculture industries to prepare for change. To that end, NRDC has been strongly advocating for increased research funds from the federal government and other sources to establish both national and global monitoring networks. We are also partnering with Woods Hole Oceanographic Institute and Duke University on a study to identify where ocean acidification will have the most acute effect on coastal communities.  Monitoring has protected businesses in the Pacific Northwest, and can be a strong tool for the future.
  • Third, just as taking care of your health can help you withstand disease, so can increasing the health and resilience of marine ecosystems soften the effects of changing pH. We may be able to mitigate the potential effects of ocean acidification by addressing other environmental stresses such as water pollution, low-oxygen dead zones and overfishing. The U.S. National Ocean Policy is helping us to put healthy oceans front and center as we manage ocean industries in our country.

The science documented in the IPCC report shows clearly that ocean chemistry is changing just as surely as climate due to our carbon emissions. Now it’s time to act on that information and protect a resource vital to our citizens and our future. 

Photo: Paul Edmondson