There is an ancient, living, vast world beneath the surface that literally carries the memory of every storm and every calm moment after. Covering more than 70 per cent of Earth’s surface, regulating our climate, generating half of the world’s oxygen, and sustaining the livelihoods of billions, the ocean is the single most consequential ecosystem on the planet. On World Oceans Day 2026, we mark not only its extraordinary scale and complexity, but the weight of our collective responsibility toward it.

This year’s theme, ‘Reimagine’, is an invitation to finally see clearly what has always been there: a living, breathing ecosystem. We have long treated the ocean as something distant from our daily lives, when in fact it underpins the air we breathe, the food we eat, and the climate stability that makes human society possible. With world leaders now committed to protecting at least 30 per cent of the ocean by 2030, and the High Seas Treaty entering into force, the framework for meaningful action exists and what we now require is the will to follow through.

Last year, I had an unforgettable experience in Cape Town, experiencing the Great African Sea Forest with Craig Foster and Swati Thiyagarajan of the Sea Change Project. I remember being immersed in the deep blue sea and seeing this wonderful ecosystem of kelp forests stretched into the ocean.

I was intrigued by the biodiversity of marine life within it and the soft might of the kelp. Being immersed into the Kelp Forest made me feel like I was in a forest under water, and despite the cold of the waters, I could see clearly how interlinked the green of the land is to the blue of the ocean.

Supporting life on Earth

Kelp forests such as those on the Cape Coast invite us to reimagine a world of oceans that we may not so easily see. In fact, the Great African Sea Forest is the world’s only “sea bamboo” stretching more than one thousand kilometres from Namibia’s desert coast down to the tip of South Africa.

Because of how rare some marine ecosystems are, this theme encourages us to rethink humanity’s connection to not only them but the oceans which house them. It serves as a call to move beyond simply harvesting ocean resources and instead become active dedicated stewards of the sea.

This call couldn’t come at a more important time as we can no longer ignore our oceans. About 80 percent of marine pollution comes from land based activities, causing rapid changes to entire marine ecosystems. The ocean itself tells us this story of our lack of care as rising temperatures have warmed marine ecosystems, industrial waste, oil spills have choked marine life, and plastic pollution has drastically affected our oceans too.

Our usual focus is so terrestrial that it feels as if we have forgotten the role the ocean plays in supporting life on Earth.

Oceans contribute food and shelter and they provide about half of the oxygen that we breathe. It is also the chief climate regulator and one of the planet’s greatest tools for capturing carbon dioxide emissions and excess heat. Without healthy oceans, there can be no stable climate, no thriving biodiversity and no sustainable future for humanity.

Importance of our oceans

Oceans must take centre stage in conversations on climate change and biodiversity loss. Scientists estimate that 91 per cent of ocean species are yet to be classified and more than 80 per cent of our ocean is unmapped, unobserved and unexplored. If environmental destruction were to persist, I wonder what we may lose without even knowing. What is encouraging is that this year Marine Protected Areas (MPAs) surpassed the 10 per cent mark. Another 20 per cent is needed to reach a 30 per cent goal. With world leaders now committed to protecting at least 30 per cent of the ocean by 2030, and the High Seas Treaty, winner of the 2025 Earthshot Prize in the “Revive Our Oceans” category, having entered into force in January 2026, the framework for meaningful action exists: countries are now legally bound to support the conservation and sustainable management of high-seas biodiversity, closing the regulatory gaps that will prove critical in achieving our climate and biodiversity objectives.

For Kenya and Africa, this conversation is timely. Next week between June 16 and June 18, the 11th Our Ocean Conference (OOC) will be held in Mombasa, guided by the theme “Our Ocean, Our Heritage, Our Future”. It is the first time OOC will be held on African soil and it will place a global spotlight on ocean action and leadership across Africa and highlight the unique coastal communities, biodiversity and ecosystems of Kenya and East Africa. Africa as a whole has 38 coastal or island states and the importance of our oceans cannot be unstated. The Swahili coast itself, where the conference will be taking place, too, is complex with histories of communities coming together for trade, fishing and cultural exchanges.

This conference in Kenya hopes to engage the private sector and deliver investment in the sustainable blue economy, empower and elevate youth leaders, catalyse ocean finance, collaboratively combat illegal, unreported and unregulated fishing, and advance marine conservation and restoration efforts. Our blue economy is not simply about extracting more value from the ocean, but it is also about ensuring economic development occurs alongside ecological protection. The ocean provides us with a potential to heal both ourselves and our planet. Nature often reminds us that restoration is possible when we choose stewardship.

As attendees gather in Mombasa, the success of the conference will not be measured by the speeches delivered but by whether governments, businesses, communities and individuals act with the urgency oceans demand. We cannot build a climate-resilient future while neglecting our oceans.

Ms Mathai is the MD for Africa & Global Partnerships at the World Resources Institute and Chair of Wangari Maathai Foundation