CARBOOCEAN 4th annual meeting

This assessment is carried out through the largest European funded research project on marine carbon research ever: the Integrated Project CARBOOCEAN which is highly policy relevant (see also: http://www.carboocean.org).

Since starting industrialisation around 1750, mankind has increasingly released CO2 to the atmosphere which significantly contributed to human induced climate change. The atmospheric CO2 content would even be higher if it was not for that at present about 25% of annual CO2 emissions are absorbed by the ocean. However, since temporal and spatial details of this sink are not yet accurately quantified, the CARBOOCEAN-project (contract no. 511176 GOCE) is dedicated to an improved quantification of the oceanic uptake of anthropogenic CO2 .

Within CARBOOCEAN, basic research is carried out which delivers a best possible prediction of future greenhouse gas forcing. Marine observations, process studies, and high-end computer models are combined in this cooperative research project on marine carbon cycling. The CARBOOCEAN Consortium consists of 50 international high-level research groups from Belgium, Denmark, France, Germany, Iceland, Morocco, the Netherlands, Norway, Poland, Spain, Sweden, Switzerland, United Kingdom, Canada, and the USA.

CARBOOCEAN is funded under EU´s 6th Framework Programme and coordinated by the Bjerknes Centre for Climate Research, a Norwegian Centre of Excellence. The international project office is located at the Geophysical Institute of the University of Bergen. The project receives 14.5 million € support from the European Commission over 5 years. The project started on 1 Januar 2005.

Recent CARBOOCEAN research results reveal a higher than anticipated year-to-year variability in marine uptake of human-produced CO2 both from direct measurements of surface ocean CO2 partial pressure and from reconstructing the human-produced carbon inventory, a task which is difficult to carry out in view of the large natural carbon background value in the ocean. In particular, the sub-polar and polar oceans show a strong variability in uptake of human-produced carbon both the in the northern North Atlantic as well as in the Southern Ocean (Antarctic Ocean). The variability in air-sea CO2 fluxes is coupled to the annual and decadal variability of the physical climate system. Changes in biological productivity and ice cover can modulate the air-sea CO2 flux considerably, with as yet difficult to quantify specific feedback rates to climate change. This means that the oceanic uptake kinetics (the “speed” of uptake) has to be controlled in future by a considerably improved network of marine carbon observations in order to check the efficiency of the marine carbon uptake mechanisms with time.

Controlled experiments on natural plankton communities in so-called “meso-cosms” reveal the possibility of enhanced biological carbon production and nutrient utilization efficiency at high CO2 levels. Changes in ocean pH value and carbonate saturation will show soon significant effects from the sea surface down to the ocean sediments in several 1000m depth. For the first time, the meta-stable calcium carbonate fraction “aragonite” has been simulated explicitly in a global biogeochemical ocean general circulation model. For a realistic CO2 emission scenario, a reduction of the biological aragonite production is predicted to amount to 29% globally and 69% for the high latitude oceans at the end of this century. Implications for the marine food chain may be severe, but are not yet identified in detail. Model projections reveal that an undersaturation of Arctic Ocean surface waters with respect to aragonite is unavoidable if atmospheric CO2 concentrations are not stabilized below 450 ppm (preindustrial atmospheric concentrations were 280 ppm, concentrations in 2009 are around 385 ppm). CO2 emissions in the 21st century will continue to significantly affect the global carbon cycle and climate change even by year 3000. Therefore, severe reductions inhuman-produced greenhouse gas emissions have to be realized now.