Direct air capture — the technology that sucks carbon dioxide directly from the atmosphere — currently costs between $400 and $1,000 per tonne of CO₂ removed at early full-scale plants. Venture capitalists love it. Climate conferences celebrate it. The startup nation, predictably, is pouring money into it. But the most effective carbon capture technology ever devised requires no breakthrough engineering, no proprietary membranes, no Nobel-calibre chemistry. It requires a shovel.

Controlled burial of biomass — wood waste, treated timber, agricultural residues — is the oldest and cheapest form of carbon sequestration on earth. It is also, by a wide margin, the most undervalued. And Israel, of all places, may be uniquely positioned to exploit it.

The science nobody wants to talk about

The principle is embarrassingly simple. Organic carbon, buried in engineered conditions that exclude oxygen and water, does not decompose. It sits there. For centuries. For millennia. A landmark 2024 study published in Science by Ning Zeng and colleagues at the University of Maryland examined a log buried 3,775 years ago in compact clay soil and found carbon loss of less than five per cent. The wood was near-perfectly preserved. The researchers proposed “wood vaults” — engineered burial sites using clay seals to maintain anaerobic conditions — and estimated a global sequestration potential of up to ten gigatonnes of CO₂ per year.

The standard objection is methane. It is valid for conventional landfills but largely irrelevant for purpose-built biomass vaults, which select feedstocks that produce negligible methane — woody biomass and stable cellulosic material, dried below the threshold at which microbial life can function. Graphyte, a US firm backed by Bill Gates, does exactly this, drying and compressing waste biomass into blocks before burial and selling carbon removal credits at between $100 and $150 per tonne with costs expected to fall further.

Current wood vault projects run at $100 to $200 per tonne of CO₂ sequestered. Zeng’s team estimates optimised costs of $30 to $100 per tonne within ten to twenty years. A separate study in the Proceedings of the National Academy of Sciences arrived at approximately $60 per tonne. Compare any of these with direct air capture at five to ten times the price.

Hiriya: an accidental proof of concept

Israelis know the Hiriya story as environmental redemption. For decades, the site southeast of Tel Aviv was the country’s largest landfill — sixty metres high, sixteen million cubic metres of refuse. It closed in 1998, was capped, landscaped, and reimagined as Ariel Sharon Park. The ugly became beautiful.

But beneath the parkland and the cycling paths, twenty-five million tonnes of buried material remain. No study has specifically quantified how much carbon is sequestered in the Hiriya mound — and that is itself revealing. The site has sixty gas wells extracting methane, generating electricity for the entire facility and feeding surplus power to the Israel Electric Corporation. The infrastructure for managing buried carbon already exists. What does not exist is the framework for recognising it as a climate asset.

Hiriya is not a purpose-built carbon vault. It is messier, less controlled, and full of materials that a well-designed burial facility would exclude. But it demonstrates the foundational principle: buried material, in the right conditions, stays buried.

The Negev as carbon bank

If you were designing a landscape for engineered carbon burial, you would specify arid climate to minimise water infiltration, stable near-surface geology, sparse population, and existing transport infrastructure. The Negev’s surface conditions — extreme aridity, negligible rainfall, high evaporation — match these requirements closely. Biomass burial operates at shallow depths, just metres below ground, so the complex deep aquifer systems beneath the Negev are not directly at risk, though any site selection would require proper hydrogeological assessment.

Israel spent seventy years making the desert bloom. The next strategic use of that desert may be precisely the opposite — not growing things, but burying them.

Honesty demands confronting the obvious weakness. Israel has about six and a half per cent forest cover, much of it JNF plantations, against a global average of thirty-two per cent. Its agricultural waste streams are modest. A Negev burial programme would almost certainly need to import biomass — from Mediterranean neighbours with surplus agricultural residues such as Turkey, Egypt, and southern Europe — which introduces transport emissions that erode the cost advantage. This is not a fatal objection. It is a design constraint. The arid geology is the asset. The biomass is the input. Israel becomes a sequestration service provider: countries with biomass but without suitable burial geology pay for the storage. The Negev becomes not a desert wasteland but a carbon bank.

From startup nation to storage nation

The voluntary carbon credit market was valued at roughly four billion dollars in 2024 and is projected to reach somewhere between seven and thirty-five billion by 2030. The total carbon market — compliance and voluntary combined — could reach into the trillions. Sequestration capacity will become a tradeable commodity.

The economics point one way. Engineered biomass burial requires low capital expenditure, scales incrementally, and depends on no technological breakthroughs. Graphyte aims for five million tonnes per year by 2030. The largest operational direct air capture facility in the world — Climeworks’ Mammoth plant in Iceland — has a nameplate capacity of just 36,000 tonnes per year and fell far short of that in its first year of operation. The scale differential is staggering.

So why does the startup nation keep backing the speculative bet? Because Israel’s innovation culture — its greatest economic strength — creates a systematic bias toward novelty. The venture capital ecosystem rewards technical complexity and exponential upside narratives. It does not reward digging holes in the desert. This is a behavioural finance problem dressed up as a climate policy debate.

The Israel Innovation Authority or the Ministry of Energy could commission a feasibility study for a Negev pilot site tomorrow. The science is published. The cost data exists. The commercial precedents — Graphyte in Arkansas, Carbon Lockdown in Maryland — already exist. What is missing is not knowledge but will.

The cheapest tonne wins

In a decarbonising world, the country that can remove a tonne of carbon most cheaply holds a strategic advantage — the same structural advantage that low-cost energy producers hold today. The competition is not between good and bad technologies. It is between expensive and cheap ones.

Israel does not need to abandon its climate technology sector. But it does need to recognise that the best carbon capture is not the cleverest. It is the most cost-effective. And the most cost-effective carbon capture is, and always has been, a well-engineered hole in the ground.

The Negev is waiting.

BIO CHAR: https://link.springer.com/journal/42773

© The Times of Israel (Blogs)