Carbon offsetting: does it actually work?

Carbon offsets are real financial instruments with genuine potential — and a long track record of falling short. Understanding how they work is the best way to use them wisely, or to decide your money is better spent elsewhere.

What carbon offsets are

A carbon offset represents a reduction or removal of greenhouse gases — typically one tonne of CO2 equivalent — achieved somewhere in the world, which is then sold to someone else to "compensate" for emissions they've made. You pay a project to store, avoid or remove carbon on your behalf, and in theory the net effect on the atmosphere is zero.

The voluntary carbon market lets individuals and organisations buy offsets independently of any regulatory scheme. Prices vary widely, from a few dollars to over a hundred per tonne, depending on the type, quality and certification.

Main types of offset

Offsets fall into two broad families:

Avoidance and reduction credits — these fund projects that claim to prevent emissions that would otherwise have occurred:

• Forest protection (REDD+): paying landowners not to cut down forest that was at risk of deforestation.
• Renewable energy: building wind or solar capacity in regions still reliant on coal — though the additionality argument is weakening as renewables become mainstream and cheap.
• Methane capture: capturing methane from landfills or livestock operations before it escapes into the atmosphere. Methane is a potent warming gas, so genuine projects here can have real impact.
• Improved cookstoves: replacing open fires with more efficient stoves in low-income regions, reducing wood or charcoal use.

Removal credits — these fund the active drawing down of CO2 already in the atmosphere:

• Tree planting and reforestation: the most widely sold offset, though with significant permanence risks (see below).
• Soil carbon and biochar: storing carbon in agricultural soils or in charcoal-like material — promising but still hard to measure reliably at scale.
• Direct air capture (DAC): technology that pulls CO2 directly from the air and stores it underground. Currently expensive and small in scale, but offers high permanence.
• Blue carbon: protecting or restoring coastal ecosystems — mangroves, seagrass, salt marshes — that store carbon in sediment.

Removal-based credits are generally considered more credible than avoidance credits, because they actually pull carbon out rather than claiming credit for something that might not have happened anyway.

The real problems

A series of investigative reports and peer-reviewed studies have found that a significant share of offset credits on the voluntary market do not deliver the reductions they claim. The core problems are:

• Additionality: the project might have happened anyway, without the funding. A forest that was never going to be cut down cannot claim credit for saving it. This is hard to prove, and some audits have found that projects significantly overstated the baseline threat.
• Permanence and reversal: a forest planted today can burn, be logged, or die in a drought decades before it has absorbed the promised amount of carbon. Climate change itself is increasing wildfire risk in many forested regions, creating a troubling feedback loop. When forests burn, the stored carbon returns to the atmosphere, but the offset credit has already been sold and "used."
• Double-counting: some credits are counted by both the project host country (towards its national climate targets) and the buyer. The same tonne of reduction cannot legitimately cancel two parties' emissions.
• Over-claiming: satellite-based analysis of several major forest protection schemes has found that actual deforestation reductions were substantially lower than the credits issued.
• Very cheap, low-quality credits: the cheapest credits on the market are often cheap because they are unlikely to deliver. A headline price of a dollar or two per tonne should prompt serious scepticism.

The golden rule: reduce first

No offset is perfectly equivalent to not emitting in the first place. Emissions released today are real and immediate; the corresponding removal or avoidance is uncertain, future, and conditional. The hierarchy should always be:

1. Reduce emissions at the source — travel less, use less energy, eat fewer carbon-intensive foods, buy less stuff.
2. Where you cannot yet reduce — for example, essential long-haul travel, or heating a home while you wait for a better system — consider offsetting as a supplement, not a substitute.
3. Support systemic change: advocacy, policy engagement and investment in clean technology infrastructure have the potential to move far more emissions than individual offsets.

How to choose higher-quality offsets

If you've reduced what you can and want to offset a remaining portion, these factors distinguish better projects from worse ones:

• Look for recognised third-party standards. Gold Standard and Verra's Verified Carbon Standard (VCS) are the most widely used. The Science Based Targets initiative and newer high-integrity initiatives are also raising the bar. No standard guarantees quality, but verified projects are at least independently audited.
• Favour removal over vague avoidance. Direct air capture and enhanced weathering store carbon with high certainty. Reforestation with long-term land protection is more credible than uncertified tree planting. Methodologically complex avoidance claims (e.g. "this forest would otherwise have been cut down") deserve extra scepticism.
• Prioritise durability. Forest projects should have buffer pools or insurance mechanisms to cover reversal risk. Geological storage (as in DAC) is the most permanent option currently available.
• Demand transparency. The project registry should be publicly accessible with detailed monitoring data. If you can't look up the specific project and its audits, be cautious.
• Be willing to pay more. Higher-quality, independently verified removal credits cost more. That's often a feature, not a bug — it reflects real cost of genuinely reducing carbon.
• Avoid bundled or anonymous credits. Know specifically which project your money funds. Generic "offset your flight" buttons that don't name the project or standard are a warning sign.

Be sceptical of "carbon neutral" and "net zero" product claims

Many products and companies now advertise themselves as "carbon neutral" or "net zero." These claims are sometimes legitimate, but often rely heavily on cheap avoidance offsets of questionable quality. Regulators in several countries have begun scrutinising and in some cases challenging such claims as misleading.

When you see a "carbon neutral" label, useful questions are: what standard was used? What types of offsets? Were emissions measured across the full supply chain, or just selected parts? Has it been independently verified? A company confident in its claims should be able to answer all of these clearly and publicly.

Better uses of your money and effort

Before spending money on offsets, consider whether the same money might achieve more:

• Cut your own emissions directly. Insulating your home, switching to a more efficient heating system, or flying less will permanently reduce future emissions without any of the uncertainty of offsets.
• Support organisations working on systemic change. Policy advocacy, clean energy transition projects, and community resilience work can affect far larger flows of emissions than individual credit purchases.
• Invest in proven removal technologies. Some organisations allow direct investment in or donation to high-integrity permanent removal projects — biochar, enhanced weathering, or DAC — where the science and permanence are more robust.

None of this means offsets are worthless. A well-chosen, high-integrity offset is better than nothing. But the voluntary carbon market has a real quality problem, and the burden of proof is on the buyer to check.

How to vet an offset: checklist

• Is the project independently verified by a named, recognised standard (Gold Standard, Verra VCS, or similar)?
• Can you look up the specific project in a public registry and read its audit reports?
• Is the project additional — would it genuinely not have happened without offset funding?
• Is it removal-based, or if avoidance, is the baseline deforestation threat credibly documented?
• Is there a buffer or insurance mechanism to handle reversal (e.g. if forest burns)?
• Is there no risk of double-counting with the host country's national climate target?
• Is the price suspiciously low? (Very cheap credits warrant extra scrutiny.)
• Have you already reduced your own emissions as much as practically possible?