Marine Scientists Issue Monaco Declaration Calling for Immediate Action to Reduce Ocean Acidification
More than 150 leading marine scientists from 26 countries are calling for immediate action by policymakers to reduce CO2 emissions sharply so as to avoid widespread and severe damage to marine ecosystems from increasing ocean acidification—the “other CO2 problem”. They issued this warning in the Monaco Declaration, released on 30 January.
The scientists note that ocean acidification is already detectable, and that it is accelerating. They caution that its negative socio-economic impacts can only be avoided by limiting future atmospheric CO2 levels.
The Monaco Declaration is based on the Research Priorities Report developed by participants at last October’s 2nd international symposium on The Ocean in a High-CO2 World, organized by UNESCO’s Intergovernmental Oceanographic Commission, the Scientific Committee on Oceanic Research (SCOR), the International Atomic Energy Agency (IAEA) and the International Geosphere Biosphere Programme (IGBP), with the support of the Prince Albert II of Monaco Foundation and several other partners.
The chemistry is so fundamental and changes so rapid and severe that impacts on organisms appear unavoidable. The questions are now how bad will it be and how soon will it happen. The report from the symposium summarizes the state of the science and priorities for future research, while the Monaco Declaration implores political leaders to launch urgent actions to limit the source of the problem.—James Orr, Marine Environment Laboratories (MEL-IAEA) and chairman of the symposium
The ocean absorbs CO2 from the atmosphere at a rate of more than 20 million tons per day, thus removing one-fourth of the anthropogenic CO2 emitted to the atmosphere each year and reducing the climate-change impacts of this greenhouse gas. However, when CO2 dissolves in seawater, it forms carbonic acid. As this “ocean acidification” continues, it decreases both ocean pH and the concentration of carbonate ion, the basic building block of the shells and skeletons of many marine organisms.
The rate of current acidification is much more rapid that past natural changes. Surface ocean pH has already dropped by 0.1 units since the beginning of the Industrial Revolution. This rate of acidification has not been experienced by marine organisms, including reef-building corals, for many millions of years, notes the Research Priorities report. The future chemical changes that will occur in the ocean as a result of increasing atmospheric CO2 are highly predictable.
Across the range of IPCC SRES scenarios, surface ocean pH is projected to decrease by 0.4 ± 0.1 pH units by 2100 relative to preindustrial conditions (Meehl et al, 2007). A previous natural ocean acidification event that occurred approximately 55 million years ago at the Paleocene-Eocene Thermal Maximum (PETM) is linked to mass extinctions of some calcareous marine organisms (Zachos et al., 2004). After the PETM’s relatively rapid onset of acidification, which could have lasted for many centuries or millennia, it exhibited a slow recovery period that spanned millions of years.
Today’s anthropogenic “acidification event” differs because it is human-induced and because it may be occurring much more rapidly. Previous natural acidification events may have been associated with the five major coral mass extinction events that are known to have occurred during Earth’s history (Veron, 2008). Recovery from the current large, rapid, human-induced perturbation, if left unchecked, will require thousands of years for the Earth system to reestablish even roughly similar ocean chemistry (Archer, 2005; Montenegro et al., 2007; Tyrrell et al., 2007; Archer and Brovkin, 2008), and from hundreds of thousands to millions of years for coral reefs to be reestablished, based on past records of natural coral-reef extinction events (Veron, 2008).—“Research Priorities”
According to the experts, ocean acidification may render most regions of the ocean inhospitable to coral reefs by 2050 if atmospheric CO2 levels continue to increase. It could lead to substantial changes in commercial fish stocks, threatening food security for millions of people as well as the multi-billion dollar fishing industry.
The Monaco Declaration is a clear statement from this expert group of marine scientists that ocean acidification is happening fast and highlights the critical importance of documenting associated changes to marine life.—Professor Sybil Seitzinger, Executive Director of the International Geosphere-Biosphere Programme (IGBP)
The Declaration urges policymakers around the world to develop ambitious, urgent plans to cut CO2 emissions drastically to prevent severe damages from ocean acidification.
Ocean acidification can be controlled only by limiting future atmospheric CO2 levels. So-called geo-engineering strategies that would not aim to restrict future atmospheric CO2 concentrations would not reduce ocean acidification. Mitigation strategies that aim to transfer CO2 to the ocean, for example by direct deepsea disposal of CO2 or by fertilizing the ocean to stimulate biological productivity, would enhance ocean acidification in some areas while reducing it in others.
Climate-change negotiations focused on stabilizing greenhouse gases must consider not only the total radiation balance; they must also consider atmospheric CO2 as a pollutant, an acid gas whose release to the atmosphere must be curtailed in order to limit ocean acidification. Hence, limits (stabilization targets) for atmospheric CO2 defined based on ocean acidification may differ from those based on surface temperature increases and climate change.—Monaco Declaration
In a paper in the journal Science published in July 2008, a team of researchers warned that the ecological and economic consequences of ocean acidification are difficult to predict but possibly calamitous, and that halting the changes already underway will likely require even steeper cuts in carbon emissions than those currently proposed to curb climate change. (Earlier post.)
Position Analysis: CO2 and climate change: ocean impacts and adaptation issues (Antarctic Climate & Ecosystems Cooperative Research Centre)