The Path towards 1.5 degrees Celsius. CEPS Policy Brief No. 336, 3 December 2015

In less than one year, the country-led exercise in preparing Intended Nationally Determined Contributions (INDCs) has accomplished what the top-down approach characteristic of the UNFCCC has not been able to achieve in over 21 years of negotiations, namely to produce a sound agreement to reduce climate change. As such, the UNFCCC should adopt a new process similar to that used in developing the INDCs, in which Parties to the Convention would mobilise their national efforts, but on a wider scale and under certain agreed binding conditions. To ensure a comprehensive engagement, this Policy Brief recommends the introduction of a four-tier system in which the most developed nations called upon to take the lead, but with the very least developed nations also contributing to the intended UN objective.

Dissolved organic carbon in sediments of the central Arctic Ocean collected during POLARSTERN cruise ARK-XXVII/3 from August-September 2012

Marine organic matter (OM) sinks from surface waters to the seafloor via the biological pump. Benthic communities, which use this sedimented OM as energy and carbon source, produce dissolved organic matter (DOM) in the process of remineralization, enriching the sediment porewater with fresh DOM compounds. We hypothesized that in the oligotrophic deep Arctic basin the molecular signal of freshly deposited primary produced OM is restricted to the surface sediment pore waters which should differ from bottom water and deeper sediment pore water in DOM composition. This study focused on: 1) the molecular composition of the DOM in sediment pore waters of the deep Eurasian Arctic basins, 2) whether the signal of marine vs. terrigenous DOM is represented by different compounds preserved in the sediment pore waters and 3) whether there is any relation between Arctic Ocean ice cover and DOM composition. Molecular data, obtained via 15 Tesla Fourier transform ion cyclotron resonance mass spectrometer, were correlated with environmental parameters by partial least square analysis. The fresher marine detrital OM signal from surface waters was limited to pore waters from < 5 cm sediment depth. The productive ice margin stations showed higher abundances of peptides, unsaturated aliphatics and saturated fatty acids formulae, indicative of fresh OM/pigments deposition, compared to northernmost stations which had stronger aromatic signals. This study contributes to the understanding of the coupling between the Arctic Ocean productivity and its depositional regime, and how it will be altered in response to sea ice retreat and increasing river runoff.