The spectre of climate change looms, despite the recent pledges by various governments to, among other things, steer clear of fossil fuels like coal or halt deforestation. But eco-friendly chest thumping aside, many of these lofty goals making the headlines will only come to fruition in decades. In the meantime, carbon-spewing machines keep chugging along, temperatures rise, and sea levels along with them.

In short, it isn’t too crazy to start looking for a way to harness the ocean surface – which already covers more than two-thirds of the Earth’s surface – whether that be floating hotels, stadiums or farms. Enter Green Ocean, an ambitious project by Japan-based architecture firm N-Ark in partnership with Cultivera, a Japanese agri-tech firm. The premise of the oceanborne farm is simple – harnessing our world’s vast reserves of seawater as a direct nutrient source for crops.

(Related: Could cities floating on the ocean be the solution to land scarcity?)

The farm will be hosted on a platform the firm dubs Arktecture, a portmanteau that combines ark (the biblical kind), technology and culture. Said Arktectures are fashioned from thinned wood, coated for extra buoyancy, and held together by salt-resistant carbon joints.

They comprise two primary systems – an underwater space for the cultivation of algae, phytoplankton and other oceanic flora that feeds the actual food growing space above sea level. Plants grown there will be fed by a mixture of seawater and, to balance out the salinity and alkalinity of the stuff, rainwater (funnelled through the structure’s inward-sloping, solar-panelled roof). The cold seawater doubles up as air-conditioning, cooling the farm. 

(Related: How Singita is designing the sustainable safari experience of the future)

Green Ocean’s key selling point is the creation of a farm with “circular functionality in terms of the vegetable’s air-conditioning and nutrition systems,” says CEO of N-Ark Yuki Tazaki.

According to N-Ark’s website, Cultivera are the brains behind the seawater farming technology that makes Green Ocean possible. The plants are kept in a humidity-controlled environment on proprietary fibres, only 5mm in diameter, that reproduce what it’d be like to have 15cm of natural soil – and supposedly requires only a tenth of the water necessary compared to conventional farming with irrigation.

If you’re wondering what the cultivation of algae and phytoplankton’s for, that’s mainly for the good of the sea (and us). After all, algae isn’t just a vital part of the oceanic food chain. It’s also a producer of oxygen via photosynthesis, and plenty of it.

(Related: Anders Berensson Architects propose the world’s largest carbon dioxide storage facility)

As for the veg that we’re able to eat, only leafy vegetables can be grown for now, though they hope to start experimenting with other veg like tomatoes in the next stage, Tazaki tells us. Overall, they’re still in the prototyping stage for “testing seawater vegetable productivity and architecture functionality on the sea.” After all, the key for any alternative from the norm is feasibility and scalability – “Green Ocean has to be scalable. Otherwise, we can’t save people suffering from rising sea levels or water damage,” Tazaki adds.

For more on N-Ark.