Climate change is the biggest threat to mankind. It is the elephant in every room, only a whole lot more deadly. The good news is that globally we are doing a whole lot to slow down the negative effects. The bad news is that we might have already passed the tipping point’ as our C0² surpasses 400 parts per million (ppm). Thus, to save the World, we not only need to block the harm we are doing now but reverse generations of human planetary abuse.

Well, our world has radically cooled in the past so why don’t we replicate the mechanics that caused one of these events?

Among the larger of those events was the Azolla Event 49 million years ago. A small adorable plant called the Azolla fern caused the world to go out of a hot-house, together with palm trees and turtles residing at the poles, to the beginning of the fridged Ice Ages. The epitome of miniature yet powerful, you can still find these adorable plants in lakes and ponds around the globe.

But how does a tiny plant cool the entire world? Its superpower is that it is great at growing and really very good at dying… Allow me to explain.

49 million years ago the Arctic appeared very different, all of the landmasses were bunched up about it, there were no ice caps and it had a nice climate. This left the Pole resemble a temperate sea cut-off from the remaining oceans. It had a couple of straights to connect it, but nothing more. This meant that currents such as the Gulf Stream couldn’t mix up the Arctic waters so it was really still. What is more, high rainfall on the continents poured tonnes of nutrient-rich freshwater (namely phosphorus and sulphur compounds) to this tranquil saltwater.

What this created was a distinctive environmental cocktail as the saltwater and freshwater didn’t blend — in fact think elaborate cocktail, James Bond-style, but not shaken rather than stirred. The heavy denser saltwater sank to the bottom and stayed there just like your sugary cocktail syrups and also the freshwater stayed on the top like your lighter spirits.

Since there was no mixing the saltwater coating had next to no oxygen. On the other hand, the surface of freshwater was highly oxygenated and obtained months of continual sunshine! In such balmy waters, Azolla flourished. This little plant grows rapidly, reproduces quickly and expires remarkably fast too. To top it off, Azolla needs minimum nourishment, and they get all of their nitrogen in the atmosphere. This implies that they can blossom and die off without draining a lot of the nutrients out of the water. Thus, every summer there was a huge Azolla bloom round the Arctic, potentially covering the entire sea. Afterward this grand bulk of Azolla rapidly died.
Whenever these ferns died they sank into the syrupy saltwater below. As there was virtually no oxygen, there was no bacteria to breakdown the plant matter.

This lack of decomposing is the reason the Azolla had such a massive impact on the air as it locked CO² into the seabed. Let’s dig a bit deeper…

The huge majority of any organism is made from carbon and plants get their carbon in the atmosphere. They take in CO², use the carbon to construct their body and release the oxygen. Ordinarily, when a plant dies it’s consumed by an animal, fungi or bacteria — to cut a long story short these organisms reunite the plants carbon to the air in the kind of CO² and methane through respiration or decomposition. This is known as the Carbon Cycle. But Azollas were not recycling the carbon, but rather were burying it in the seafloor.

Thus, Azolla’s knack for growing fast with little nutrients and dying quickly, together with a sour seafloor along with a freshwater high layer made a super-efficient carbon sink.
This effect was so great that over the span of the Azolla Event (800,000 years) these ferns pulled 80% of the CO² from the atmosphere! The CO² concentration went in the wapping 3500 parts per million to 650 parts per million.

We’re currently around 410 parts per million CO² that is lower than if those Azolla ferns were around. Our ecosystems have evolved for this colder climate and warming them up too fast can wreak havoc. To get our CO² levels back to pre-industrial revolution levels (in other words to undo human-made climate change) we need to reach sub 300 parts per thousand.

Nowwe don’t need to cause a second Ice Age. I think I speak for everyone once I say I like my summer holidays! But could we exploit this kind of natural carbon sink to fight climate change issue? Time to get a little maths, but don’t worry, I’ve done it all for you!
Well, normally, the Azolla Event decreased global CO² annually by 0.0035625 parts per thousand. That means to take our 410 ppm into 300ppm would take 30,877 decades.

If we replicated one of the fastest cooling events in the planet’s history it’d take over 30,000 decades to undo the atmospheric harm we have done in the last 70 years. This should show you precisely how fast the planet is changing up now and just how difficult it’s to undo the changes we have set in motion.

If we could neutralise our own CO² emissions during the next few decades, then we can keep CO² degrees under 450 ppm. But even then it will still require tens-of-thousands of years to restabilise the atmosphere — but at geologic time scales that is nothing. If we want the human race to live long term, and not just be a blip in the Earth’s long term, we will need to reset the international climate to shield us and the ecosystems we depend upon.

Therefore, if we could neutralise our CO² in 450ppm, repeat the Azolla Event and become very patient we can undo climate change!

But there is only one problem. After all, the global cooling of the Azolla Event came from an whole sea being flipped into an Azolla farm. We will need to replicate the Arctic sea 49 million decades back and its’ conditions without having a global effect.
Sadly, there is not any component of the planet now that closely resembles the Arctic 49 million years ago, so we will need to be a little more hands-on . We can not section off a part of the seas as we’ll interrupt the important oceanic balance and possibly alter all of the ocean’s biodiversity. But, lucky for us, Azollas are freshwater plants. Unfortunately, such a huge presence of water would distrust weather patterns and international nutrients. For example, the Amazon has been fed nutrients from the arid, dusty wind that sweeps in the Sahara Desert.

So rather than using an artificial lake, we can engineer some of the world’s biggest lakes to be our plantation. This means the ocean isn’t influenced by our plantation, and unlike creating completely fresh human-made lakes, we won’t be messing with weather patterns too much.
The ancient Arctic sea was 4,000,000 km² (1,500,000 sq mi) which is only a smidge bigger than the biggest lake in the world by surface area, the Caspian Sea in 371,000 km² (143,000 sq mi). We could add a bigger lake to top up the surface area, something such as the Lake Malawi in 29,500 km2 (11,400 sq mi). If we use these two lakes, we have enough surface area to replicate our sea.

We can engineer these lakes to huge Azolla farms. Primarily we need to kill off all native life, after which by closely monitoring what goes in the lakes, we could engineer the oxygen dead zones around the bottom along with the nutrients needed to kick start an Azolla Bloom. What’s more, with modern farming procedures, we could have an even greater rate of CO² absorption compared to the original Azolla Event by making sure that we always have perfect conditions.
Now, ruining unique ecosystems in these lakes does not sound like a great way to save the planet, does it? However, to create these Azolla powered carbon sink, then you need to. Can this sacrifice worth the reward? I don’t understand, that is not for me to pick.

So, can Azolla save the entire world? Quite possibly, but it would come in a massive sacrifice and using a degree of devotion never done by humans before. We would have to desecrate some of the world’s most distinctive habitats and work tirelessly for tens-of-thousands of decades just to reverse 70 years of human activity. So it’s questionable whether this method could be used or even should be used. In the very least this puts the scale of climate change to a sharp focus.
Having said that, there may be another way to create Azolla carbon dioxide, like closed-off tubes of hydroponics, which could work in less biodiverse areas like desserts without changing global weather patterns. Additionally, there are lots of other ways of pulling carbon out of the air like utilizing atmospheric carbon to generate graphene batteries. Azolla is one of many tools we have to fix our biggest problem.