The real payoff from the Apollo missions had nothing to do with the moon. The prize was travelling far enough out into space to look back properly at planet Earth. Those two unforgettable images – Earthrise and Blue Marble – showed us our fragile and precious planet, defined by its blue. Since then, we’ve talked proudly about our “blue planet” but without thinking any further about what that blue actually is. We talk about fish and whales, plastic and pollution – the things that are in the water – but not the water itself. The great ocean engine has just kept turning while we scurry about near its surface, only caring when its churning causes something dramatic that we can see – an algal bloom or a giant swarm of jellyfish.
More than 50 years after Apollo, the ocean is starting to get more attention, but a growing slice of the discussion is based on the assumption that it is there for us to use, a resource to be exploited, a great volume of “nothing” that human inventiveness is going to turn into “something”. And this is incredibly dangerous. Unless humanity starts to see the ocean for what it really is – a critical part of our planetary life support system – we risk sleepwalking into destruction.
Things are starting to change. The ocean was formally mentioned in the Paris climate agreement of 2015, but it was only in 2019 that an “ocean and climate change dialogue” became part of the UN’s climate COP processes. We’re hearing about the importance of the sea for the Earth’s carbon cycle, and possible changes in ocean circulation due to polar ice melt. But alongside all that, there’s a detectable assumption that the sea is available space to expand into. We’ve filled up the land with our buildings, infrastructure and agriculture, and just look at that vast expanse of water, waiting for humans to give it a purpose!
The two most obvious examples of this are schemes to use the ocean to take up more carbon from the atmosphere, and to mine critical minerals from the deep sea. Carbon dioxide removal schemes do not allow us to keep burning fossil fuels – the focus must be on rapid decarbonisation – but they will be necessary in a few decades’ time to reach our current climate goals and maybe even reverse some of the damage. Some of the proposed technologies involve using the sea as a carbon sink, and advocates for scaling them up often give the impression that all this blue is just a giant pond to be exploited, ignoring the fact that the 3D ocean engine is intricately structured and that its living components are already under considerable stress.
You can’t “just” fertilise the ocean, or change its alkalinity, or park huge new farms there, or dump billions of tonnes of biomass into the deep sea without affecting the existing ocean physics, chemistry and biology. I have frequently heard engineers and businesspeople state that they have two aims – to restore a pristine ocean and to make the ocean do the clearing up for us by taking up carbon, producing vast quantities of seaweed as a material resource, or whatever this week’s scheme is. That betrays an ignorance of just how intricately woven together the ocean’s systems are, and how interlinked the whole thing is. It is also the language of control dressed up as concern for everyone else’s welfare. Of course, restoring ocean ecosystems is beneficial for lots of reasons, and it will have climate benefits, but we need to focus on the restoration, not manipulating the ocean environment to do stuff for us before we fully understand how it works now.
Tracking the long term net effect of these ocean carbon uptake schemes is incredibly difficult, because it’s hard to predict how much carbon they will move from the atmosphere to the ocean and whether it will stay there. We don’t yet have the science (known as “measurement, reporting, and verification”, or MRV) to be sure that any of these interventions in the ocean would work. And it ignores what the sea is already doing for us. Before the industrial era, it was a small source of carbon dioxide to the atmosphere, but now it takes in around 25% of all our carbon emissions. That’s 10bn of the 40bn tonnes of CO2 we emit every year. When it comes to removing carbon from the atmosphere, the ocean is already doing us a gigantic favour, and we are still working out whether we will continue to benefit from that favour in the future.
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Back in 1858, the Great Stink of London finally convinced the politicians of the day to find a way to pay for Joseph Bazalgette’s sewer system, as they accepted that the Thames was overwhelmed with human waste, the slop from abattoirs and tanneries, and the general dross of a huge and dirty city. But the language of the time talked of the Thames itself being the problem, rather than recognising that this tidal estuary had been quietly disposing of London’s disgusting mess for centuries. If anything, the Thames was due an enormous thank you for allowing the city to ignore its excesses for so long, and an apology for being biologically ruined in the process.
We are guilty of this same attitude with the sea all the time – the assumption that it’s a place called “away”, which makes pollution vanish, and that access to this convenience is a natural right rather than a failing of our own systems. We’ve used the sea as a dump for years – not just for sewage, but for toxic materials, space junk, unwanted munitions and far more – and it’s high time we stopped.
Dismissal of the idea that the ocean matters is apparent in a different way with deep-sea mining. There are vast areas of the deep sea floor that are covered with “polymetallic nodules” – potato-sized lumps rich in manganese, nickel, copper and cobalt. The nodules take millions of years to form in this incredibly calm environment. These plains are home to a phenomenal array of strange life that drifts and crawls across the nodules, secure in the darkness and the quiet.
The advocates of mining these nodules give their investors the impression that there is nothing there that matters so the mining is consequence-free. But of course that’s not true. These are delicate ecosystems that are difficult to study, and we’re still picking apart the basics. Two things are clear: any mining would generate huge plumes of sediment that would have great effects downstream, and monitoring the mining carefully enough and for long enough to check for the full environmental consequences and compliance with regulations would be extremely hard to do. Society needs to have the debate about the pros and cons of this – maybe the eventual decision will be that it is a necessary trade-off – but you can’t start from the assumption that the ocean isn’t doing anything of value down there already.
I’m not saying that we shouldn’t have any ocean infrastructure. Offshore wind is going to be a critically important energy resource, and there may be places where tidal and wave energy generation is the best option. But even these projects should start from the recognition that there is already a physical fluid engine and an ecosystem there, and we should understand that and minimise our influence on it as we stamp our mark on the sea.
The ocean of salty water that surrounds our planet has layers, currents, an intricate structure and a very dynamic existence. Life is woven through the physical engine, its locations and abundance dictated by the character of water produced by the swirling, flowing patterns generated by a liquid engine on a spinning planet fed with solar energy.
Life in the sea is different from life on land. On land, a tree is our model for the best of the natural world: huge, decades or centuries old, stationary, a reliable feature in a fixed landscape. In the sea, about 60% of the biomass is too small for us to see with the naked eye, and it has rapid, fleeting lives with no long-term storage of resources. These living passengers form the foundation of the ocean food chain, and there is almost as much photosynthesis in the sea as there is on land (although it’s not true that the ocean generates half the oxygen we breathe, because almost all of the oxygen produced in the ocean is consumed in the ocean). The dolphins are lovely, but to think that sea life is all about such charismatic megafauna is to miss the point.
It is time to move on from this language and this mindset. What if we could look at the remains of Earth’s last great wilderness and have some humility in how we approach it? The first deep sea explorer, William Beebe, travelled into the depths in a small metal sphere with tiny windows, which he described as “dangling in a hollow pea on a swaying cobweb a quarter of a mile below the deck of a ship rolling in mid-ocean”. He knew his place: a visitor to an alien world, there to look and admire, not to plunder or conquer or modify. We need to shift our view of exploration from drawing maps to understanding processes. And we need to shift our expectations for our activity in the sea from creating our own processes to fitting in with the ones that are already there.
Our planet is defined by its ocean, and therefore so are we. We cannot afford to speak of the ocean as though it is simple or empty or worthless. We have to see this dynamic engine as a critical part of our existing planetary life support system, in whose shadow we are privileged to live. Instead of seeing the ocean as a “solution” for climate change, we need to see it as a test of a new attitude to our planet, one that doesn’t treat it as a combination of universal rubbish bin and exploitable resource. Ask not what the ocean can do for you, but what you can do for the ocean.
Blue Machine: How the Ocean Shapes Our World by Helen Czerski is published by Torva (£20). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply
