b'FLUXES The European Greenhouse Gas BulletinPhoto: Pekka Pelkonen, ICOS RIDisparity between different domainsObservation-based MRV systems have not developed equally in all fields. While there are developments and projects based on atmospheric observations, ecosystem and ocean observation MRV systems are not as advanced for a number of reasons.One of the underlying reasons behind this disparity comes down to countries reporting requirements, suggests Professor Alistair Manning from the UK Met Office. Lets look at oceans. Countries have to report their own emissions, so why would they report emissions from, say, the mid-Atlantic, if they dont have to? They are not required to go beyond their borders.More generally, most human-related emissions take place over land and are required to be reported. Processes like ocean fluxes have no formal reporting requirements and so they are given far less attention, he adds.For the land ecosystem, the story is different. LULUCF is an important sector in official reporting, and so ecosystem modelling is extensively investigated, says Manning.But ecosystem modelling is really tricky because there are many significant uncertainties - the respiration of trees at night, the activity of bugs in soils, the list goes on. Things change by the hour. Therefore, it is really hard to upscale information from small field trials to the national level.'