Third in our biochar series. The first piece told you where biochar came from. The second told you how it works in soil. This one is about everything else people now say it can do — and which of those claims you can actually take to the bank.

Walk past almost any palm oil mill in Nigeria at the end of a working day and you will see the same thing: a pile of cracked palm kernel shells, smoking. Burning them is the cheapest way to make the heap disappear. Down the road, a sawmill is doing the same with its sawdust. A cashew processor is doing it with its shells.

That smoke is the start of this story. Because the same waste going up in it, treated a slightly different way, turns out to be one of the most useful materials in the climate toolbox. Not in a lab. On the kind of farms and in the kind of businesses that fill this region.

Biochar is sold today as a fix for almost everything: carbon, crops, dirty water, even cow burps. Most of those claims are built on real science. The trouble is that the people selling it keep the big number and lose the small print. So here is the version with the small print left in, because the small print is where the truth lives.

It quietly fights three pollutants, not one

Everyone talks about biochar storing carbon. That is the heart of what we do, and it is real. But the carbon it locks in the ground is only part of what is happening.

Soil also leaks two other gases that are far nastier than carbon dioxide, ton for ton. One of them, nitrous oxide, holds hundreds of times more heat. The other, methane, holds dozens of times more. They come off farmland quietly, and almost nobody notices them.

When biochar is worked into a field and kept up year after year, a large 2025 study that pulled together 438 separate trials found it cuts both of those gases noticeably, on top of the carbon it buries. You do not see it. The soil just leaks less of the bad stuff.

The catch worth knowing

This is the reward for sticking with it over several seasons, not a one-time trick. Add it once and walk away and the effect fades. And on waterlogged land like rice paddies, it can sometimes do the opposite. Right soil, long game. That is the rule.

The scale, if the world bothered, is enormous

Here is the part that sounds made up but is not. That same study did the math on all the crop waste the world burns or dumps every year. If just 70% of it were turned into biochar instead, it would cancel out almost 5% of all the pollution the world produces from burning fossil fuels. Every year. From rubbish. And it would grow extra food on the side — roughly a third of what the United States harvests in grain annually.

The catch

That is the dream scenario — the absolute ceiling if everyone did it everywhere. And on its own, the farming benefit pays for only about four-fifths of the cost of making biochar. The piece that closes the gap is selling the stored carbon to companies that need to offset their own pollution. That is not a side hustle. It is what makes the whole thing add up — and it is exactly how our model is built.

It can clean water too

That black, sponge-like structure that helps soil hold onto nutrients does something similar in water. It grabs poison out of it.

Scientists writing in 2025 found that specially prepared biochar can pull more than 90% of heavy metals like lead out of dirty water, and strip out most of the microplastics floating in it too. For a continent where clean water is not a given, that is a big deal.

The catch

Those headline results come from biochar that has been treated and tuned, tested on clean water under lab conditions. Drop ordinary farm char into a real, murky drain and it works less well. The promise is real and the research is racing ahead, but this is tomorrow's product, not something you bolt onto a borehole today.

The cow story: exciting, but don't bet the farm

You may have read that feeding biochar to cattle cuts the methane they belch. Some trials do show that — by a tenth or so, with the animals none the worse for it. For a region with a lot of cattle, it is a tempting idea.

Be careful here

The very same researchers found that once the cows were out grazing in a field instead of penned and measured, the effect vanished. Scientists themselves call the results in this area mixed and contradictory. So treat "biochar fixes cow burps" as a hopeful maybe, not a fact. Anyone selling it to you as proven is getting ahead of what we actually know.

For some countries, this is a national-scale lever

In 2023, researchers mapped biochar's carbon potential country by country. Twelve countries could lock away more than a fifth of their entire national emissions just by charring their crop waste. The top of that list was not a rich Western nation. It was Bhutan, at 68%, with India close behind.

The catch

That is what is physically possible, not what has been built. It assumes you can gather up all that waste and that nobody else needs it. But notice the pattern: the countries with the most to gain are farming nations in the tropics. That is us.

Why all roads lead back here

Step back and the same lesson keeps showing up. Biochar is not magic dust that helps a little everywhere. It is a tool that helps a lot in particular places: hot, wet, tired, acidic farmland, sitting next to businesses that throw away tonnes of plant waste every week.

Read that description again. It is West Africa, almost word for word. The soils that benefit most are the soils our farmers work. The waste that becomes biochar is already piling up at our mills. The need is sharpest right here.

That is the whole idea behind BIG. We take what the mill already burns — the palm kernel shells, the cashew shells, the sawdust — and turn it into biochar that goes back into local soil while the carbon it traps earns real money from companies abroad paying to offset their pollution.

One waste stream, two incomes: better land, and a cheque for the carbon.

The hype around biochar is finally catching up to the evidence. And the honest version of the story turns out to be the more exciting one, because it points straight at the soil under our feet and the smoke rising off our mills.

If your business makes that kind of waste, it is worth more than the cost of burning it. That is a conversation worth having.

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