Climate action requires new accounting guidance and governance frameworks to manage carbon in shelf seas

Abstract

Accounting guidelines exist for the recording of carbon flows in terrestrial and coastal ecosystems. Shelf sea sediments, while considered an important carbon store, have yet to receive comparable scrutiny. Here, we explore whether effective management of carbon stocks accumulating in shelf seas could contribute towards a nation's greenhouse gas emissions reduction targets. We review the complexities of carbon transport and fate in shelf seas, and the geopolitical challenges of carbon accounting in climate governance because of the transboundary nature of carbon flows in the marine environment. New international accounting guidance and governance frameworks are needed to prompt climate action.

Fig. 1. Transport of carbon across territorial boundaries.

Input, production, transport and storage pathway of carbon in marine waters, including movement across maritime zones of national jurisdiction: territorial sea, Exclusive Economic Zone (EEZ), continental shelf, high seas, and deep seabed. The rights within each territorial boundary and marine zone relevant to carbon management in the marine environment are summarised for each zone.

Fig. 2. Transport of carbon on the North West European shelf.

Illustrating the inflows and transport pathways for carbon in the marine environment, including movement across agreed Exclusive Economic Zone (EEZ) boundaries between [11] countries: (FR) Faroe Islands; (GB) Great Britain; (IRL) Ireland; (F) France; (E) Spain; (B) Belgium; (NL) Netherlands; (D) Germany; (DK) Denmark; (S) Sweden; (N) Norway. Source for coordinates of EEZ boundaries: http://www.marineregions.org/eezmapper.php. The main transport pathways on the North West European shelf^,, are based on the main water flow (residual pathways), which will transport particulate and dissolved forms of carbon and sediment. The flows are largely driven by tides, wind driven transport, and density driven flows driven by temperature and salinity differences or by Atlantic inflow (white). They vary in strength, rate and depth depending on season and many cross national EEZ boundaries. EEZ and bathymetry (blue scale) from http://portal.emodnet-bathymetry.eu/#. Adapted from Hill et al. and Luisetti et al..