The ocean already has a shared carbon observing system. Repeat hydrography, ship lines, floats and moorings, supported by nations together, put the ocean sink at about 3 GtC a year, a quarter or more of our emissions. Nobody has written down what that system costs, what would make it good enough to verify a tonne of carbon removal, or what a shared system would save compared with every project measuring the ocean for itself.
Three white papers answer those three questions, about one system at three moments. Each is written with the programmes and groups that hold the numbers, and each is written only if its numbers come back.
What the current system costs
The first network-by-network cost of the ocean carbon observing system, next to the uncertainty it buys.
Paper 1, March 2027 → 2What would make it MRV-grade
The accuracy and density verification requires, and the advances in sensors, platforms, autonomy and models to get there.
Paper 2 → 3What a shared system saves
The cost of one shared system against every project doing its own MRV, as a function of scale, and where it pays for itself.
Paper 3 →Why now
The ship-based carbon data stream has been shrinking since 2017 while the demand on the system is growing. Carbon-removal projects must detect their own small signal against the background ocean, and since October 2026 the London Convention and Protocol frameworks expect every research experiment at sea to show rigorous monitoring. Every project pays to measure the same background on its own.
The background ocean is a public good. A shared system, the one we already have made MRV-grade, measures it once. These papers put a cost on today's system, a specification on the upgrade, and a number on the saving.