Around 650 million years ago an explosion of algae kick-started human life. Now, this broad group of aquatic organisms could hold the key to help humanity in a very different way - or so says one start-up that is growing algae in the Moroccan desert.
When microscopic algae get the right surge of nutrients from an ocean current, they can multiply exponentially, creating swirling blooms that ripple through the ocean in a range of eye-catching colours from lime green and yellow to turquoise and electric blue.
Algae aren't plants, nor animals either, but they do photosynthesise as they grow. The thousands of algae species that exist together remove more carbon dioxide from the atmosphere even than forests, pumping out oxygen in exchange.
"Algae are the unsung heroes of carbon removal," says Adam Taylor, whose UK-based company Brilliant Planet is tapping their potential to combat climate change.
Every year, countries are emitting about 37 billion tonnes of carbon dioxide by burning fossil fuels, and counting. That figure is supposed to reach almost zero in less than 30 years, to fend off further global heating.
Algae is responsible for about half of all of that carbon dioxide that gets removed.
Brilliant Planet, a start-up backed by venture capital and Innovate UK, the government’s innovation agency, wants to increase that figure by replicating those blooms on land.
It’s growing algae in its pilot site in Akhfennir, a sleepy coastal town in the desert in southwest Morocco. This reddish Saharan landscape, where not even a blade of grass grows, now hosts bright green ponds that are teeming with life.
Using wind power, they pump in seawater to feed the local algae species, which grow at pace for about 30 days, before being harvested.
“We then dry the algae and bury it in the desert, and that keeps that carbon removed from the atmosphere, locked away for thousands of years,” explains Mr Taylor, the CEO.
The dried algae flakes are so dry, salty - up to 40% salt - and acidic, they’re effectively mummified before they’re buried in a semi-sealed “tomb”.
"From a technical perspective, it's impossible for it to rot," says Mr Taylor.
The process also de-acidifies the sea-water, which is then pumped back out to sea.
Carbon offsetting's bad reputation
Brilliant Planet is one of numerous companies around the world developing “carbon removal” technology.
It can be a risky business, but one we cannot afford to live without to reach climate goals, the UK’s Climate Change Committee and UN scientists say.
Brilliant Planet will sell the carbon removed from the atmosphere as credits to companies that have not or cannot yet cut their own emissions, so want to offset them instead.
But that will take time, and carbon offsetting doesn’t have the best reputation.
It can be hard to prove its efficacy. For example tree-planting can be foiled by disease or wildfires, and solar farms, which generate offsets by "avoiding" emissions from a fossil fuel power plant, may have gone ahead anyway.
Stuart Gilfillan, who tracks and verifies CO2 storage at Edinburgh University, says the carbon market is still new and “lacks consistent regulation”.
“Verification that the amount of carbon claimed to be removed, is actually being removed, for good, is critical," he says.
Taylor says when they promise to remove a tonne of carbon on behalf of another company, "we can be very sure that we've actually done that".
That's because they can verify it and measure it, including on their site on an agri-business centre in Harpenden, Hertfordshire.
In one of their labs, which are brimming with packets of dried out algae and the “AlgaeTron AG 230” incubator, they burn the algae in a small furnace to test how much carbon it stores.
For every square metre of algae pond, they absorb as much as 30 square meters of forest, every year.
They hope to build their first commercial site of 1,000 hectares by 2027, subject to further fundraising. This site would absorb 100,000 tonnes of carbon dioxide a year - the equivalent to the yearly emissions of around 20,000 Britons.
Although that’s a drop in the ocean of global emissions, they say they've identified enough suitable land - around 500,000 square kilometers, roughly twice the area of the UK - to remove over three billion tonnes of carbon per year.
New technology warning
But Dr Ajay Gambhir, senior researcher at Imperial College London, says any new technology brings a risk of “unknowns”, and does not scale quickly.
At every stage, companies must check “there are no side effects, no issues that you haven't thought of coming up,” says Dr Gambhir, who specialises in the technology required to transition to a low-carbon economy.
“Having said that, we do need to move really fast,” he adds. “Emissions are still rising. That’s a really terrible situation to be in.”
First, we need to cut those emissions urgently, he says.
“And then those carbon removal technologies - which, if we're lucky, work at scale, don't have adverse side effects, come in at a reasonable cost - can be deployed to offset the remaining emissions."
The other risk is that offsetting makes society “complacent”, he says, so we continue to burn fossil fuels in the hope that "someone, somewhere will come along in the future and clean up the mess with carbon removal technologies”.
Dr Gilfillan says climate change is such an enormous challenge, we need "a range of technologies and ideas, such as increased renewables, energy efficiency, switching to lower carbon fuels, electrification of transport and capture of CO2 from industrial sources.”
Mr Taylor agrees "the primary focus does need to be on reducing emissions".
But even if we do rapidly cut them - which at the moment globally we're not - there will still industries like flying that will be very difficult to stop from polluting, Mr Taylor says.
"And for those cases, we will need carbon removal.”
Humans are still benefiting from that algae explosion hundreds of millions of years ago.
Today, it seems these organisms have the potential to undo some of the damage we have done to our planet since then.
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