Carbon dioxide (CO2) emissions are causing ocean acidification to progress at an unprecedented rate, a new American research has found.
According to the summary of a congressionally requested study by the National Research Council, the changing chemistry of the world's oceans is a growing global problem.
It adds that unless man-made carbon dioxide (CO2) emissions are substantially curbed, or atmospheric CO2 is controlled by some other means, the ocean will continue to become more acidic.
The long-term consequences of ocean acidification on marine life are unknown, but many ecosystem changes are expected to result.
The US government's National Ocean Acidification Program, currently in development, is a positive move toward coordinating efforts to understand and respond to the problem, according to the study committee.
The ocean absorbs approximately a third of man-made CO2 emissions, including those from fossil-fuel use, cement production, and deforestation, the summary points out.
The CO2 taken up by the ocean decreases the pH of the water and leads to a combination of chemical changes collectively known as ocean acidification.
Since the beginning of the industrial revolution, the average pH of ocean surface waters has decreased approximately 0.1 unit - from about 8.2 to 8.1 - making them more acidic.
Models project an additional 0.2 to 0.3 drop by the end of the century.
This rate of change exceeds any known to have occurred in hundreds of thousands of years, the report says.
The ocean will become more acidic on average as surface waters continue to absorb atmospheric CO2, the committee said.
Studies on a number of marine organisms have demonstrated that lowering seawater pH with CO2 affects biological processes like photosynthesis, nutrient acquisition, growth, reproduction, and individual survival depending upon the amount of acidification and the species tested, the committee found.
While changes in ocean chemistry caused by increasing atmospheric CO2 can be determined, not enough information exists to assess the social or economic effects of ocean acidification, much less develop plans to mitigate or adapt to them, the committee noted.