Dear reader — I am writing this from a fishing village called Henningsvær, with the smell of diesel and saltfish in my coat, on the second evening of a three-week stay with the Lofoten Kelp Cooperative. The lamp on the table is one of those small enamel things that has been here since the 1960s. The dog at my feet is called Frost. I begin every dispatch by telling you where I am, because the where is most of the story.

This is, properly, a letter to the members. But our editor has asked that I post a copy in the journal this quarter, as several of you who are not yet members have written to ask what we actually do out here. So: what we actually do.

The work, in plain words

Twice a week, weather permitting, four divers from the cooperative descend to a kelp meadow about a kilometre off the coast. They are mapping the meadow — not its whole extent, which is several hundred hectares, but a series of permanent transects laid out in 2022, each marked with steel pegs driven into the seabed.

On each transect they take photographs with a calibrated stereo camera, count plant density in standardised quadrats, and clip ten frond samples for laboratory analysis. The frond samples are weighed wet on the boat, then dried and weighed again at the small laboratory in Bodø. The dry weight is what we care about — that is biomass, which is mostly carbon, which is what the credit pays for.

That is the whole protocol. There is nothing here that anyone with a dive certification, a sharp knife, a careful temperament and access to a precision balance could not do. The point is to keep doing it, in the same place, in the same way, for thirty years.

What we don't know

Kelp is, in honest terms, the hardest of the carbon storage stories to tell. A forest stays where it is. A bog stays where it is. A kelp meadow loses fronds constantly — they break off, drift, sink. Some of that carbon sinks to the deep ocean, where it stays out of the atmosphere for a thousand years or more. Some is eaten by sea urchins six metres away and immediately recycled. The fraction that "counts" depends on the local depth, the currents, the season.

The cooperative has spent three years instrumenting this. They have current meters at five depths, sediment traps at the meadow edge, and a small remotely-operated vehicle on loan from the University of Tromsø. Even with all of that, the published number for sequestration per hectare carries an uncertainty band of about thirty percent. We publish the band. We will not publish the midpoint without the band.

"We will not publish the midpoint without the band. The honest carbon market is the one that admits what it does not know."

This is not as marketable as a tidy round number. It is, we think, the only honest version of the work.

Why the cooperative exists at all

Lofoten kelp has been declining for forty years, mostly because of warming seas and a population boom in green sea urchins. The cooperative does not plant kelp — the meadow is wild — but it manages urchin density, removes ghost gear, and protects the area from bottom-trawling by working with the local fisheries authority. Without that management, the meadow would be smaller by now. We can show you the time series.

This is what additionality looks like in practice. Not "we planted a thing." Closer to: "we held the line on a thing that was already there, and would have shrunk without us."

The boat, the dog, the kettle

I will end where these letters end — with the small things. Tonight the cooperative is hosting a dinner for the divers, the laboratory team in Bodø who handles the dry-weight measurements, and three of our members who happened to be in the country. We will eat poached cod and boiled potatoes. We will not talk about carbon for the first hour. Frost the dog will be under the table looking for fish skin. Outside, the dark is total, and the sea — the sea, I am told, is calm tonight, which is generous of it.

If you would like to come to one of these visits, the spring intake opens in March. We accept a small number of buyers, and an even smaller number of custodian organisations. The cod is always good.

With warm regards from a cold place —

Ingrid