9 September 2014: The World Meteorological Organization’s (WMO) annual Greenhouse Gas (GHG) Bulletin indicates that the concentration of GHG in the atmosphere reached a record high in 2013 due to a surge in carbon dioxide levels, making international action on climate change all the more urgent. According to WMO Secretary-General Michel Jarraud, atmospheric carbon dioxide concentrations increased in 2013 at the fastest rate in nearly 30 years, with carbon dioxide remaining in the atmosphere for many hundreds of years and for even longer in the ocean.

The WMO’s Global Atmosphere Watch network observed that carbon dioxide levels increased more between 2012 and 2013 than during any other year since 1984. Global carbon dioxide atmospheric concentrations reached 396 parts per million (ppm) in 2013, with the global annual average carbon dioxide concentration expected to surpass 400 ppm in 2015 or 2016 if the current rate of increase continues. The GHG Bulletin reports on atmospheric GHG concentrations, not emissions. While emissions represent what goes into the atmosphere, concentrations are what remain after the atmosphere, biosphere and oceans interact. The ocean absorbs approximately 25% of total emissions and the biosphere takes up another 25%.

While the ocean may absorb carbon dioxide from, and reduce carbon dioxide concentrations in the atmosphere, this causes the rate of ocean acidification to increase. Thus, for the first time, the GHG Bulletin includes a section on ocean acidification. Jarraud underlines that “If global warming is not a strong enough reason to cut carbon dioxide emissions, ocean acidification should be.” For example, calcifying organisms, such as corals, algae, mollusks and some plankton, depend on the abundance of carbonate ion to build shell or skeletal material via calcification. However, for many organisms, calcification decreases with acidification. [WMO Press Release] [Publication: WMO Greenhouse Gas Bulletin]