The Global Climate Observing System (GCOS) is launching an open review of the current requirements for Essential Climate Variables (ECV) that are the basis for the global systematic observation of the climate system. GCOS would like to invite as wide a possible range of reviewers to participate. This is the first step in a revision and update of the requirements planned for 2021/2. Revisions to the existing ECV and ECV products or proposals for new ECV or ECV products can be made and support for the existing requirements is also encouraged. These requirements are intended to be user requirements: what is needed by users. We encourage the marine biogeochemistry community to review these user requirements, in particular the ones set for Ocean Biogeochemistry ECVs: Inorganic Carbon, Nitrous Oxide, Nutrients, Ocean Colour, Oxygen and Transient Tracers - all of which have their corresponding Essential Ocean Variables (EOVs) as defined by GOOS.

Comments should be submitted by end of 2017 using the on-line form at:

 https://www.research.net/r/ECVRequirements.

Established in 1992 by WMO and other partners, GCOS maintains a list of ECV that are required to understand the climate system, to monitor changes in it and to be the basis of planning to mitigate or adapt to changes in the climate system. GCOS recognises that observation capabilities improve and the needs of users change over time. Thus, the list of ECV and their requirements must evolve as well. The current list of 54 ECVs and their individual observation requirements were published in the recent GCOS Implementation Plan and welcomed by the UNFCCC at its meeting in Marrakech in November 2016. 

More information about ECV and this review can be found HERE. The ECV requirements can be downloaded by selecting the following links:

• the threshold, a value that should be achieved for the data to be of use
• the goal, a value beyond which no further benefit can be derived, and
• intermediate values for specific applications.