Calcarea targets ~$76 / ton CO2 Pilot reactor headed for a Lomar cargo ship in 2026 Up to half a ship's emissions, caught in the wake Shipping emits ~1 gigatonne of CO2 a year From Caltech garage to onboard carbon capture Calcarea targets ~$76 / ton CO2 Pilot reactor headed for a Lomar cargo ship in 2026 Up to half a ship's emissions, caught in the wake Shipping emits ~1 gigatonne of CO2 a year From Caltech garage to onboard carbon capture

Jess Adkins - tenured at Caltech, on leave to chase a gigatonne.

Founder / Scientist / CEO

Jess Adkins

He read carbon in ancient corals. Now he catches it off a smokestack.

A chemical oceanographer who spent twenty years decoding how the deep sea quietly buffers the planet's carbon - then bolted that same chemistry onto cargo ships. His startup, Calcarea, scrubs CO2 with limestone and seawater and leaves it stored in the ship's wake.

1998PhD, MIT / Woods Hole

~50%Ship CO2 captured

$76/tTarget cost of storage

2026First shipboard pilot

The Dispatch

A reactor on the back of a boat

Picture a steel tank bolted to the deck of a container ship. Exhaust that would normally vanish up the funnel gets routed into it instead, bubbled through seawater and a bed of crushed limestone. What comes out the other side is, more or less, saltwater. The carbon dioxide that went in does not float back to the sky. It leaves as bicarbonate, the same dissolved salt the ocean has used to balance its books for millions of years, trailing behind the hull and staying put. That tank is the whole idea behind Calcarea, and Jess Adkins is the man feeding exhaust into it.

Adkins is the co-founder and CEO. He is also, still, the Smits Family Professor of Geochemistry and Global Environmental Science at Caltech - a named chair he reached in 2017 after seventeen years climbing the academic ladder. Most professors who reach that perch stay on it. Adkins took a leave and went to build hardware. His pitch is not that capturing carbon is novel. It is that doing it cheaply, on equipment that already moves the world's freight, might actually scale. Shipping pumps out roughly a gigatonne of CO2 every year, in the same league as aviation, and it has stubbornly few ways to clean up. Calcarea wants to be one of them.

The number that makes people lean in is the cost. Calcarea aims to store carbon for around seventy-six dollars a ton. The leading direct-air-capture systems hover near a thousand. That gap is the entire thesis, and Adkins is blunt about why it matters: a climate fix only sticks if the spreadsheet works.

Origin

The garage question

The company did not start in a boardroom. It started in lockdown, in the back of a garage, with a scientist talking himself into something. Adkins had spent decades on deep curiosity - deep-sea corals, stalagmites from Borneo, sulfur isotopes, the slow chemistry of how calcium carbonate dissolves on the seafloor. Fascinating work. None of it was built to ship.

Then he asked himself the uncomfortable question - what is the single most important thing I could be doing - and the honest answer was not another paper. It was getting carbon out of the atmosphere at scale. The strange luck was that he had already, accidentally, done the groundwork. A decade studying limestone weathering kinetics had taught him something useful: the reaction that eats limestone speeds up sharply at around five percent CO2. Cargo-ship flue gas runs at roughly that concentration. The lab curiosity and the industrial smokestack turned out to be a match.

He had never led a startup. He built the rest of the founding team around the gaps: Melissa Gutierrez, a former Caltech undergraduate who pushes the company on environmental justice and port-community relationships; Pierre Forin, an engineer out of Norway's green-shipping world; and Will Berelson, a USC biogeochemist who had studied the same ocean chemistry from the other coast.

The inspiration even has a name from his old field: carbonate compensation, the planet's own slow trick of neutralizing CO2 against limestone over geological time. Calcarea's bet is that you can do the same thing in a tank, in seconds, on a moving ship.

The lucky coincidence

Limestone dissolves faster at ~5% CO2. Ship exhaust happens to run at about 5% CO2. A decade of pure research walked straight into an industrial use case.

Mechanics

From smokestack to seawater, in four moves

Catch the exhaust

Flue gas from the ship's engine, roughly 5% CO2, is routed into a reactor instead of out the funnel.

Meet the limestone

Inside, the gas contacts solid calcium carbonate while seawater flows through the tank.

Make bicarbonate

The CO2 reacts and converts into dissolved oceanic bicarbonate - benign, stable, permanent.

Release in the wake

The bicarbonate-rich seawater goes overboard. The carbon is stored where the ocean already keeps it.

In tests the system has scrubbed up to three-quarters of the CO2 in a stream, with a realistic target of cutting a ship's emissions by about half. No exotic solvents. No giant onshore plant. The chemistry is old; the packaging is new.

The Spreadsheet

$76 versus $1,000

Adkins is unsentimental about money. The reason Calcarea points at shipping and limestone rather than fans pulling CO2 from open air is cost per ton sequestered. Here is the gap that drives the whole company.

Calcarea (target)

$76 / ton

Leading direct air capture

~$1,000 / ton

Figures cited by Calcarea / Caltech Magazine. Bars scaled to the ~$1,000 reference.

In His Words

The founder, talking

Ultimately, what we're trying to do only works when there's an economic balance sheet.

By offering a capture technology that can be fit onto existing ships, and that can sequester CO2 in the wake, we think that Calcarea can help the industry reduce its emissions faster.

The shipping industry emits roughly 1 gigatonne of carbon dioxide per year, similar in size to the aviation industry, and has relatively few options with which to decarbonize.

Our technology offers lower energy demands, lower costs, and lower infrastructure requirements than comparable alternatives to cut emissions from shipping.

The Long Road

Three decades, one pivot

1990

B.S. in chemistry, Haverford College.

1998

PhD in chemical oceanography, the MIT / Woods Hole Joint Program.

2000

Joins Caltech as Assistant Professor.

2006 - 2010

Climbs to Associate, then full Professor.

2017

Named Smits Family Professor of Geochemistry and Global Environmental Science.

2020

The garage question. He pivots toward carbon at scale.

2023

Calcarea closes a $3M seed round.

2024

Joint development deal with Lomar Shipping's lomarlabs.

2025

Land prototype at USC; system shown cutting ship CO2 by up to half.

2026

First pilot reactor slated for a Lomar cargo ship.

Marginalia

Five things that stick

He dove for his data. Before he was a CEO, Adkins logged deep-sea research dives and oceanographic expeditions across the Atlantic and Pacific.
The byproduct is basically saltwater. What Calcarea releases overboard is bicarbonate-rich seawater - the carbon stored, the discharge benign.
A coincidence of concentrations. Limestone dissolves fastest at about 5% CO2, the exact neighborhood of cargo-ship flue gas.
First startup, late. He had never led a company until Calcarea - and started it after he was already a named-chair professor.
It grew from pure curiosity. The whole venture traces back to research on coral biomineralization and ancient climate, not a business plan.