A new paper in Nature Reviews Earth & Environment has mapped out the uncertainties that still plague enhanced rock weathering (ERW) as a carbon dioxide removal strategy. Meanwhile, Germany’s Thünen Institute — a federal agricultural research body — has gone further, calling ERW “not yet a reliable climate protection measure.”

This is getting attention, and it should. But let’s read past the headlines.

What the Paper Actually Says

The Nature paper doesn’t claim ERW doesn’t work. It catalogs the variables that make precise quantification difficult: soil type, mineral grain size, local climate, microbial activity, and leaching dynamics all influence how fast basalt dissolves and how much CO₂ is actually captured and stored.

In other words: ERW works in principle, but the how much varies enormously depending on where and how you deploy it. That’s a measurement challenge, not a fundamental flaw.

The Thünen Perspective

The German researchers are particularly cautious about over-promising. Their concern is that ERW could enter carbon credit markets before measurement, reporting, and verification (MRV) methods are robust enough to guarantee what’s being sold. That’s a legitimate worry — one shared by serious people in the CDR space.

Where CDI’s Research Fits

This is exactly the kind of uncertainty that Carbon Drawdown Initiative has been working to resolve. CDI’s EW greenhouse experiment includes a detailed four-part series on the lifetime carbon balance of ERW, addressing the LCA (life-cycle assessment) methodology that separates real CDR from hopeful estimates.

CDI’s ongoing leachate proxy series is also tackling MRV head-on — testing whether electrical conductivity, pH, and other proxies can reliably track alkalinity changes at macro and micro scales. The findings are nuanced: EC tracks alkalinity well at aggregate level, but breaks down under specific conditions like fertilizer events.

“Uncertain” ≠ “Useless”

Every CDR pathway started uncertain. Direct air capture was once a lab curiosity. Biochar permanence was debated for a decade. The question isn’t whether ERW works — it’s whether we can measure it precisely enough to build credible markets around it.

The Nature paper is a map of the work still needed. Not a tombstone.

Source: Nature Reviews Earth & Environment (2026) | Phys.org coverage

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