How Azolla Can Save The Planet
Solving the Climate Crisis by Re-Engineering What the Earth did 50 Million Years Ago
Fellow Nerds,
Climate change is no longer a looming threat. It's here. It has arrived. Hannibal has crossed the alps. And our response collectively as humanity has been, as ever, lazy and outlandish, focussed on high-tech solutions like nuking mars or finding another earth like planet in the galaxy.
Terraforming Mars or building carbon capture machines are more like sci-fi than a practical fix. We’re investing billions in projects that distract us from solutions that are far more grounded and dare I say, obvious.
Instead of fantasising about starting over on some desolate rock millions of kilometres away, why not look back at how Earth itself solved a similar problem millions of years ago? That’s right. Earth already did this once, around 50 million years ago, during the Azolla event. What if I told you that we could re-engineer exactly what nature did back then? What if we could use a humble plant to help reverse the damage we’ve caused, without the need for rockets or colonies on distant worlds?
Sounds too simple? Sometimes the simplest solutions are the most overlooked. And although simple, I never said it would be easy. So let’s talk about it. Let’s talk about Azolla.
Before we begin, I would like to give a shout out to Zoë Schlanger. It is by reading her book, The Light Eaters, that I first got introduced to the idea of Azolla as a solution for global warming. It's a great book that I definitely recommend reading.
The Azolla Event
Fifty million years ago, Earth was in trouble. The planet was in the grip of an intense greenhouse effect, with CO2 levels far higher than they are today. Tropical temperatures reached almost to the poles, and the Arctic Ocean was more like a warm, shallow lake. It was a world on the brink, teetering under the weight of its own atmosphere. But just when it seemed the planet couldn’t get any hotter, something remarkable happened.
The warm Arctic waters became a breeding ground for one of Earth’s most unassuming plants, the Azolla, a tiny aquatic fern. Conditions were perfect for this little plant to explode in growth. The Arctic Ocean, isolated from major ocean currents, was a stagnant, nutrient-rich pool, allowing Azolla to thrive in an environment with abundant sunlight and warm temperatures. It began to bloom uncontrollably across the surface, forming massive floating mats of greenery.
Azolla has the unique ability to form a symbiotic relationship with nitrogen-fixing cyanobacteria, allowing it to grow even in nutrient-poor environments. This adaptability, combined with its fast growth rate, allowed Azolla to absorb vast amounts of CO2 from the atmosphere.
As these blooms of Azolla died, they sank to the bottom of the ocean, trapping the carbon within their plant matter. Over time, this process repeated in a loop, creating layer upon layer of carbon-rich sediments. The result? CO2 levels plummeted, leading to a dramatic cooling of the planet.
What’s fascinating here is how perfectly these conditions aligned to let Azolla flourish. Earth literally engineered its own rescue. The Arctic Ocean created a greenhouse inside the greenhouse, only to allow Azolla to do what no machine ever could, i.e., pull the planet back from the brink by naturally sequestering carbon.
The Azolla event played a major role in transitioning Earth from a greenhouse world into the cooler, more temperate climate that followed. The sheer scale of this fern’s impact is staggering. It shows that natural processes, when given the right conditions, can reshape the entire climate of the planet.
Why Azolla Specifically?
Azolla is a carbon sequestration machine. Like all plants, it pulls in carbon dioxide (CO2) from the atmosphere through photosynthesis, converting it into organic matter. However, Azolla stands out because it’s incredibly efficient at this process. It has one of the highest rates of CO2 absorption among plants, thanks to its fast growth cycle and dense mats that spread rapidly across water bodies.
When Azolla dies, instead of releasing that stored carbon back into the atmosphere like many other plants, it sinks to the bottom of lakes, ponds, or oceans. Over time, layers of dead Azolla build up, trapping the carbon in sediment. This is how Azolla helped lower atmospheric CO2 levels during the Eocene epoch.
Azolla’s ability to thrive in nutrient-poor environments means it doesn’t need fertilisation or chemical inputs, which makes it an ideal candidate for sustainable carbon farming.
One of the reasons Azolla grows so rapidly is because of a unique relationship it has with Anabaena, a nitrogen-fixing cyanobacterium that lives inside the fern. Anabaena converts atmospheric nitrogen into forms that Azolla can use, making it self-sustaining even in areas with low nutrient levels.
This ability to fix nitrogen enriches the environment where it grows, turning nutrient-poor water bodies into healthier ecosystems. In some agricultural settings, Azolla has even been used as a biofertilizer because of its nitrogen content. Imagine scaling that potential to improve degraded lands or water systems while simultaneously capturing carbon. It's a win-win!
When it forms dense mats on the surface of water bodies, it provides natural shade, preventing sunlight from penetrating deep into the water. This reduces evaporation and lowers the temperature of both the water and the surrounding environment.
This cooling effect can have a multiplier effect on ecosystems. Cooler water temperatures can prevent harmful algal blooms, improve fish habitats, and reduce the heat absorbed by water bodies, which helps regulate local climates. In large-scale applications, Azolla could help mitigate the effects of urban heat islands and other localised warming effects.
Another intriguing aspect of Azolla is its potential as a source of biofuel. While biofuels made from corn or palm oil have been criticised for their environmental impact, Azolla grows quickly and doesn’t require the same level of inputs like fertilisers or irrigation. This makes it an eco-friendly alternative for biofuel production.
Azolla could be harvested and processed into biofuels, providing a carbon-neutral energy source. The carbon released when the biofuel is burned would simply be the carbon that Azolla had previously absorbed from the atmosphere, making it a closed-loop system. Unlike fossil fuels, where we’re releasing ancient carbon back into the atmosphere, biofuels derived from Azolla could offer a way to reduce reliance on fossil fuels while actively managing carbon levels.
When you combine these factors, i.e., rapid carbon sequestration, self-sustaining nitrogen fixation, cooling effects, and its potential for biofuel production, I can’t think of a reason not to farm Azolla. It’s a natural climate regulator, perfectly suited to help us combat the very problem it once helped solve millions of years ago. It doesn’t need complex machines, advanced technology, or massive energy inputs. It just needs the right conditions to do what it’s always done.
So Why aren’t We Working on This?
If you’ve read the above section in detail, you must be thinking, “if it's that straightforward, why haven’t we done this yet?” And you’d be right to ask that question. It’s proven, it’s natural, and it once saved the planet from a carbon crisis far worse than what we face today. So, why haven’t we tapped into this solution?
The answer, like most things in the fight against climate change, is a mix of ignorance, distraction, laziness, and a focus on the wrong solutions.
First off, lack of awareness plays a huge role. Most people outside the scientific community have never heard of the Azolla event. When we think of ways to combat climate change, our minds often jump to modern (read: stupid) solutions like high-tech carbon capture technologies. In contrast, Azolla seems almost too low-tech, too simple, to be taken seriously.
But what we fail to recognise is that sometimes the simplest solutions are the most powerful. The natural world has been regulating carbon cycles long before we ever got involved, but we’ve become so focused on human-engineered fixes that we’ve forgotten to look at what the planet already knows how to do.
Then, there’s the issue of distraction by flashy alternatives. It’s hard to deny that space colonisation and geoengineering capture imaginations in a way that Azolla farms just don’t. Projects like colonising Mars (by an individual who shall remain unnamed) sound visionary, futuristic, and full of promise, which makes them attractive to governments, tech moguls, and venture capitalists. These grand ideas, though, come with astronomical costs and very little guarantee of success. Yet they continue to hog attention and resources, while something like Azolla, which could be implemented right here, right now, is seen as less exciting.
There’s also a very real problem of policy inertia (read: laziness). Governments tend to fund and support what’s familiar and financially viable, like renewable energy, electrifying transportation, or reducing plastic waste. In other words, they try to delay the problem, not solve it. There’s very little financial or political incentive to explore natural methods like Azolla farming because there isn’t any financial viability in it for the politicians and bureaucrats. Scaling Azolla would require changes in agricultural practices, water management, and infrastructure, none of which are trivial undertakings.
One excuse that is often used is that Azolla grows fast, like very fast. While that’s part of its appeal as a carbon sink, it also means it can become invasive if not properly managed. Its rapid spread can disrupt local ecosystems, outcompeting other aquatic plants and even causing problems for water quality.
But these challenges, though real, aren’t insurmountable. With proper planning, regulation, and infrastructure, Azolla farming could be scaled in a way that benefits both the climate and local ecosystems. If the earth did it, we can too. The question is, are we willing to put in the work to make it happen? Or are we going to keep throwing money at distant planets and unproven tech fixes while the real solution might just be floating in a pond?
Re-Engineering the Azolla Event
Now, to address the big question, could we actually re-engineer the Azolla event today? The short answer is YES.
Scaling Azolla Farming
The idea of farming Azolla on a large scale might sound ambitious, but it’s far from impossible. In fact, small-scale Azolla farming has been happening for decades, primarily for agricultural uses, such as fertiliser or animal feed. What we need now is a push to scale these efforts for carbon sequestration on a much larger level.
We could tap into areas of the world with underutilised water bodies, from the wetlands of Southeast Asia to the man made reservoirs of the Western U.S. These Azolla farms would be relatively low-cost to set up compared to high-tech solutions like carbon capture machines or solar geoengineering.
But to make this work, we need global cooperation. Countries with large water resources could lead the way, much like reforestation efforts. Nations could designate specific zones for carbon farming, where Azolla would be grown under controlled conditions to maximise its CO2 absorption and prevent it from becoming invasive.
Water Management and Infrastructure
Growing Azolla requires water management systems. Fortunately, Azolla thrives in stagnant, nutrient-poor waters, the kind that most plants can’t survive in. This opens up possibilities for growing Azolla in areas where water quality is already poor, or where the environment is not suitable for traditional agriculture.
With the right infrastructure, we could create artificial ponds or floating farms in urban areas, industrial zones, or even deserts where water is scarce but could be recycled efficiently. These water systems would need to be managed to ensure proper growth rates and prevent overgrowth.
The good news is, we wouldn’t need the vast fertile lands that are often required for other forms of climate-friendly agriculture, like reforestation or crop-based biofuels. This allows us to focus on marginalised water bodies where Azolla could thrive without competing for prime agricultural land.
Managing Ecological Risks
One of the challenges in large-scale Azolla farming is the risk of invasiveness. Azolla grows rapidly, which means it could potentially outcompete native plants and disrupt aquatic ecosystems if not properly controlled. However, this isn’t an insurmountable problem. With proper regulation and oversight, Azolla farms can be managed to avoid the worst ecological impacts.
We could design containment strategies where Azolla is grown in isolated water bodies or floating farm structures that prevent it from spreading into natural ecosystems.
Another option would be to plant Azolla in degraded ecosystems that need restoration, effectively using it as both a carbon sink and a tool for ecosystem recovery. In such cases, the benefits of Azolla could outweigh its invasiveness, especially in areas where biodiversity has already been severely compromised.
Economic and Social Benefits
Large-scale farming of Azolla could create jobs in both developed and developing nations. From building and maintaining the water systems to harvesting and processing Azolla for biofuel or agricultural uses, there’s a wide range of economic opportunities tied to this plant.
On top of that, Azolla could be a source of low-cost biofuel for regions that need affordable energy. With the push toward carbon-neutral economies, Azolla could play a role in helping countries meet their renewable energy targets, all while pulling CO2 out of the atmosphere.
Policy and Global Cooperation
For Azolla to have the kind of impact we’re talking about, it would need to be part of a global strategy. Governments would have to incentivise carbon farming in the same way they currently subsidise renewable energy projects. International bodies like the UNFCCC could create frameworks for Azolla credits, allowing nations or companies to offset their carbon emissions by investing in Azolla farms.
In the same way that reforestation projects have gained international traction, Azolla could become the next big nature-based climate solution. It’s scalable, it’s affordable, and most importantly, it’s been proven to work.
Clock is Ticking…FAST
We are out of time. Global temperatures have risen by 1.1°C since the pre-industrial era, and if we don’t act now, we’re on track to hit 1.5°C within the next two decades. The consequences of this rise are already becoming painfully clear, wildfires, floods, extreme heat waves, and biodiversity collapse. Meanwhile, carbon dioxide levels are higher than they’ve been in 4 million years, and we’re still pumping out 36 billion tons of CO2 annually.
At a time when we need real solutions, we’re distracted by high-tech fantasies of escaping to Mars or inventing machines to undo our mistakes. But Earth has already shown us the way 50 million years ago. And yet, despite its proven ability, Azolla remains overlooked in the climate conversation.
We cannot afford this oversight any longer. If we’re serious about pulling the planet back from the brink, we need to act fast.
We need to fund large scale research and trials to explore the potential of Azolla to draw down carbon. We’re spending billions on geoengineering experiments, what not invest in something that already worked once before?
As citizens of countries across the world, it's our responsibility to push our governments to adopt nature-based climate policies. The world has committed to limiting warming to 1.5°C under the Paris Agreement, but our current efforts fall far short. We need urgent political action to make Azolla part of our carbon farming strategies.
Raising public awareness about Azolla will be key. For too long, climate discussions have been dominated by technological solutions. It’s time to remind the world that nature itself offers some of the best answers.
The truth is stark, if we don’t bring atmospheric CO2 down to 350 ppm (we’re currently at over 420 ppm), we risk triggering catastrophic climate feedback loops that could devastate ecosystems and human life.
Azolla worked once before to save the planet. It can work again, but only if we stop ignoring the obvious and start putting nature back at the centre of the climate fight.
Time is running out! Let’s not gamble our future on dreams of distant planets or untested machines. The answer could be floating on a pond, waiting for us to harness it.