Please Mow Your Lawn
The Challenge of Additionality in Carbon Markets
Markets are only a tool to reduce greenhouse gas emissions if they change business as usual
Sometimes the simplest examples reveal the most significant problems.
When a neighbour pays you to mow your lawn, something you'd do anyway, it feels like easy money. But scale this up to carbon markets worth hundreds of billions of dollars, and you've uncovered one of environmental policy's thorniest challenges.
Carbon offset schemes promise to tackle climate change by paying landowners to sequester carbon in soil and vegetation. The catch? These payments should only reward actions that wouldn't happen without the financial incentive; a principle called "additionality."
Yet many of the most effective carbon-building practices, from improved grazing to cover cropping, also boost farm productivity and soil health. This creates a problem of how to prove that carbon payments, rather than good business sense, drove the decision to change.
For mindful sceptics, this additionality challenge offers a perfect case study in questioning well-intentioned policies that may not deliver what they promise.
As we'll explore, the tension between market mechanisms and environmental necessity reveals deeper questions about how we approach climate solutions and whether paying for actions that should become standard practice might be missing the point entirely.
Please mow the lawn.
My neighbour comes over and asks a favour.
“Hey, for God’s sake, would you mow your lawn?” she says with an urgency that crosses every boundary known to civilised man. “We’re selling and, well, your lawn just… It’s a neighbourhood disgrace.”
“It is?”
“Yes. It’s terrible. Look, I’ll pay you $100 if you get it done by Friday.”
“Sure, why not,” I said.
What’s not to like about $100 for a job you would do anyway? Heck, I could even get the neighbour’s son to do it for 50 bucks.
But here is the thing.
Even if I were the laziest resident of the district, I would mow my lawn in the future, even if it was after a couple of nasty letters from the local council urging me to get on with it.
The payment from my overzealous neighbour did not change the fact that the lawn would be clipped sooner or later. All the payment did was to bring the event into her timeframe.
This is a classic example of additionality failure, non-additionality.
The payment made no material difference to the lawn mowing outcome.
This idea is crucial to how effective market mechanisms are going to be for activities that benefit the collective and hurt the individual or the corporate.
What is additionality?
Additionality is a concept that lives in the carbon markets.
The idea is simple enough. Market mechanisms are applied to incentivise activities that reduce net greenhouse gas emissions compared to business as usual. This can happen through fewer GHG emissions, the sequestration of carbon into vegetation and soil, the mechanical removal of CO2 from the atmosphere, or some combination of these activities.
The critical word is net.
Actions that the market promotes must result in a net reduction in greenhouse gases over what would have happened if the market mechanism were absent, which is the business-as-usual or baseline scenario.
Approved activities can earn credits for reducing emissions or pulling carbon from the atmosphere. When plants do this, we call it sequestration, and some of that carbon also goes into the soil.
These credits are placed in an official registry and can be purchased by entities with a carbon liability. Buyers could be individuals who want to offset a flight or companies with a heavy emissions profile that they cannot reduce, such as an aluminium smelter.
A key feature of approved activities that generate credits is that they only happen because of financing from the sale of credits. If there were no returns from credits, the activity wouldn't happen.
In other words, they are an addition to business as usual.
Here is the formal definition of additionality…
Project activity is additional if it can be demonstrated that the activity results in emission reductions or removals that are in excess of what would be achieved under a “business as usual” scenario and the activity would not have occurred in the absence of the incentive provided by the carbon markets.
All the carbon registries that hold or trade carbon credits have some form of this additionality concept built into their program.
Sometimes, the registry approves the activity as additional. More typically, each project that generates credits has to demonstrate that the activity at the project level is additional through a barrier analysis, a way of testing whether it would happen anyway.
In the lawn mowing example, my neighbour paid for an action that would have happened under business as usual. It is a baseline activity because the lawn is mown every three weeks or so in summer.
Giving me a financial incentive to mow my lawn is not additional, even though I benefit.
Permanence and risk reversal
Additionality is not the same as permanence or risk of reversal. There are rules for these attributes, too.
Carbon credits have a defined lifetime that depends on the registry's requirements. This is usually called a permanence obligation, which requires the carbon stored by a project to be maintained for the chosen period, typically 25 years, 100 years, or even in perpetuity.
Some carbon projects could go belly up. The trees might die, a wildfire could destroy the vegetation, or a drought might reduce the grass cover. There are many reasons why a project might not sequester all the carbon it claims.
Carbon registries circumvent this risk of failure problem by providing a risk of reversal buffer that reduces the carbon credits issued to a project, typically 5%, sometimes more for riskier projects.
The risk of reversal buffer is not an insurance option for the project; it is insurance for the integrity of the registry. In most instances, the project owner must reestablish carbon from fire or natural disturbance so the buffer pays for the time when the credit volume is absent.
This complexity might seem daunting, but understanding these nuances is exactly what separates mindful sceptics from those who accept simple solutions to complex problems.
But take with you the important idea that the carbon registries did everything they could to make carbon credits real. So when you hear people saying its all rubbish, a ponzi scheme or whatever, know that this is a failure of policy not a failure of the procedures.
If you are still with me, here is a closer look.
Soil carbon additionality.
The Australian government formally recognised the role of agriculture in carbon sequestration with the introduction of the Carbon Farming Initiative (CFI) in 2011, under the Clean Energy Future Plan led by the Gillard government.
The Carbon Farming Initiative Act 2011 was designed to provide a framework for farmers and landholders to earn carbon credits by adopting approved agricultural and land management practices that reduce greenhouse gas emissions or sequester carbon in vegetation and soils. This marked the first time that the federal government explicitly integrated soil carbon management into national climate policy, transitioning from earlier focus areas like energy and forestry to also include broadacre farming.
Although soil carbon had been studied and promoted by scientists and agricultural innovators for some time, it was not until the CFI that financial mechanisms were introduced to support and verify its increase as a carbon offset. This was part of a broader shift in the national climate strategy, which included carbon pricing and the eventual establishment of the Emissions Reduction Fund (ERF) under the Abbott government in 2014, which absorbed and replaced the CFI. The ERF continued to include soil carbon as one of the approved methodologies for generating Australian Carbon Credit Units (ACCUs).
Despite policy fluctuations and political resistance to broader climate action, the recognition of agriculture’s role in carbon sequestration has remained a relatively bipartisan element. Recent policy updates, especially under the Albanese government post-2022, have reinvigorated interest in soil carbon and climate-smart agriculture as part of Australia’s commitments under the Paris Agreement and the net-zero 2050 target.
In short, soils are a net zero opportunity too good to miss because most agricultural soils are depleted in carbon relative to their local potential. Beyond the sequestration, restoring carbon in soil makes good sense because it fuels biological activity and improves soil health. The sequestration potential is real but also a bonus.
In its net-zero emissions strategy, titled The Australian Way, released late 2021, the Australian government projects that up to 17 million tonnes of carbon dioxide equivalent could be sequestered through soil carbon projects by 2050. This sequestration is anticipated to generate approximately $400 million in additional revenue for landholders. This is forecasted potential revenue based on market participation and is not a direct government payment. The actual realization of this revenue depends on several variables, including the adoption rate of soil carbon farming practices, advancements in measurement technologies, and the stability of carbon credit markets.
$400 million in payments for soil carbon in 2050 sounds like a substantial sum. It would be roughly 0.3% of the predicted $131 billion agricultural output. But when spread across many farms, academics suggest that this income level will be a decisive trigger for practice change in only a tiny minority of cases.
Recall that for sequestration to be real in carbon market terms it must be additional to business as usual. The extra carbon storage in soil from keeping cover crops, reduced tillage, changes to grazing would be incentivized by the carbon payment.
The problem is that farming practices that increase soil carbon sequestration generate sufficient private benefits for some (but not all) farmers to adopt them without payments because of a general and straightforward rule…
Improved soil health increases yield and resilience to climate extremes.
And adding carbon to soil increases soil health.
As the researchers suggest
If these farmers receive payments for adopting these sequestering practices, such payments would contribute nothing to our sequestration targets, because the farmers would have adopted the practices anyway, without the payments (i.e., the sequestration is “non-additional”).
Thamo, T. and Pannell, D.J. (2016). Challenges in developing effective policy for soil carbon sequestration: perspectives on additionality, leakage, and permanence, Climate Policy 16, 973–992.
One cattle, lamb and feral goat farmer south of Cobar in Western NSW, uses 22,000 of his 122,000 acres for carbon farming. He said carbon farming is beneficial as it allows him to make some of his rougher country productive, which he usually wouldn’t earn any income from. He values it especially as a continuous, guaranteed income, enabling farmers to use it to make the property more viable.
This example reads like the farmer needs the financial incentive from carbon farming to change practice. But if the land wasn’t productive before and is now, why wouldn’t other farmers change practices anyway?
In the carbon markets, this is the problem of baseline setting when we know that practices will change over time, meaning the baseline business as usual changes too.
Soil carbon measurement
It used to be the measurement of carbon in soils that prevented market adoption of this sequestration option.
Soil carbon is technically difficult or cumbersome to measure directly because the innate variability of soil requires a huge sampling effort to obtain a reliable estimate of average carbon content. The cost of estimation became prohibitive given the volume of sequestration and the price per ton of credits. Many farmers couldn’t recover the cost of establishing a project.
Recent technical advances in measurement, including remote sensing, have eased this constraint.
More importantly, the market mechanism has allowed the modelling of soil carbon to predict sequestration followed by measurement to validate predictions as an alternative method of accounting.
This is a substantive step forward.
But as Michael Crwawford noted
The reality of soil carbon is that it is highly variable, hard to measure, shift, and easy to lose.
We are back to additionality, actions that go above and beyond business as usual and not only need carbon finance but actually result in soil carbon gains within the permanence and risk reversal rules.
We must not let these realities stop us from trying.
Soil carbon gains are not just essential to tackle climate change; they are critical to food production.
Market mechanisms
Market mechanisms to alter behaviour are one of our clever, convoluted, and capricious inventions. They work well in theory, but every nuance and rule creates opportunities for interpretation, manipulation and the risk of failure.
Additionality is essential for a carbon market to achieve emission reduction. It ensures that the activity change happens because of the mechanism.
Mowing the lawn a few days early is not additional.
Ensuring that reforestation, avoided deforestation, carbon registration into soil and other AFOLU practices would not happen anyway. They all improve soil, and ecosystem services delivery is a big ask.
The irony is that, as with the lawn mowing, they must happen anyway.
Humans are very clever. Set us a challenge and we can invent tools and tricks to achieve just about anything, constrained only by cost and the laws of physics.
Market mechanisms to influence behaviour are among our most ingenious, convoluted, and capricious creations. On paper, they’re elegant ways to nudge people toward the greater good through incentives. In practice, every rule spawns a loophole, every definition invites interpretation, and every layer of complexity brings new risks of confusion, manipulation, or outright failure.
We now know that a foundational principle of carbon markets is additionality. It’s the idea that the emission reductions or carbon sequestration would not have happened without the mechanism in place. Without additionality, the whole system is a mirage where the taxpayer or they market pays for actions that would have occurred anyway, and pretending it's progress.
Cutting your lawn a few days early? Not additional. You were going to do it anyway.
In the realm of land use that includes reforestation, preventing deforestation, improving soil carbon, and other AFOLU (Agriculture, Forestry, and Other Land Use) practices, the demand for proof of additionality is especially fraught. These are good practices. They restore degraded land, improve water retention, support biodiversity, and build ecological resilience. But under market rules, they only earn credits if we can argue persuasively that they wouldn’t have happened without the financial nudge.
And here’s the rub. These things must happen anyway. With or without credits. With or without schemes. The planet requires them. So we’re stuck in a strange game where we pretend they’re extraordinary, optional extras just to fit the rules, when in reality, they’re the very baseline of any credible path forward.
The additionality challenge reveals that environmental solutions are rarely as straightforward as they appear. As mindful sceptics, we can simultaneously appreciate the genuine attempt to create market-based solutions while recognizing their limitations.
The real question isn't whether carbon markets are perfect because they never are, but whether they're moving us in the right direction while we develop better approaches.
Mindful Momentum
The Carbon Credit Detective Challenge
Choose three companies that advertise "carbon neutral" products or services.
Visit their websites and trace their carbon offset claims back to the source projects. Look for specific details about additionality testing—do they explain how they know the carbon sequestration wouldn't have happened anyway?
This exercise develops critical evaluation skills for environmental marketing claims while revealing how rarely companies provide meaningful detail about their offset purchases.
Try this one for a more hands-on approach.
The Backyard Soil Carbon Experiment
Start a small-scale comparison in your garden, balcony planters, or even indoor pots.
Create two identical growing areas: one using conventional practices (regular digging, synthetic fertilizer) and another using carbon-building techniques (minimal disturbance, organic matter additions, cover plants).
Monitor plant health, soil appearance, and water retention over 3-6 months, longer if you can.
This hands-on approach helps you understand how soil carbon actually works while experiencing the practical benefits that make additionality challenging. I expect you'll prefer the "carbon farming" method regardless of any hypothetical payments.
Key Points
Additionality is a cornerstone principle that determines whether carbon markets actually reduce emissions. The concept requires that carbon sequestration or emission reduction activities only happen because of financial incentives from carbon credit sales, not as part of business-as-usual practices. Without genuine additionality, carbon markets become elaborate accounting exercises where buyers pay for environmental improvements that would have occurred anyway, undermining the entire system's credibility and effectiveness in addressing climate change.
Soil carbon projects face a fundamental additionality challenge because many carbon-building farming practices also improve productivity and profitability. Practices like cover cropping, reduced tillage, and improved grazing management increase soil health, boost yields, and enhance resilience to climate extremes. This creates a paradox where farmers may adopt these practices for economic benefits alone, making it difficult to prove that carbon payments were the decisive factor in changing land management decisions.
Technical advances in measurement and modelling have addressed previous barriers to soil carbon projects, but core challenges remain. While remote sensing and predictive modelling have reduced the cost and complexity of measuring soil carbon changes, the fundamental variability and complexity of soil systems persist. Soil carbon remains difficult to measure accurately, can shift between locations, and is vulnerable to loss through drought, fire, or management changes, requiring sophisticated risk management and permanence safeguards.
The additionality requirement creates a contradictory situation where essential land management practices must be framed as extraordinary to qualify for carbon markets. Reforestation, soil restoration, and improved agricultural practices are increasingly recognised as necessary baseline actions for environmental sustainability and food security. However, carbon market rules require these practices to be portrayed as additional voluntary actions that wouldn't occur without financial incentives, creating a disconnect between climate policy mechanisms and the urgent need for widespread adoption of regenerative land management.
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Curiosity Corner
This issue of the newsletter is all about…
Using the simple example of paying someone to mow their lawn, this issue reveals how carbon offset markets struggle to prove they're actually changing behaviour rather than just subsidising actions that would happen anyway.
5 Better Questions from this issue of the newsletter…
If carbon markets require proof that environmental improvements wouldn't happen anyway, how do we incentivise actions that should become standard practice? This question reveals the fundamental tension between market-based mechanisms and the urgent need for widespread adoption of sustainable practices, moving beyond whether carbon markets work to examining whether they're the right tool for the job.
When a farmer says carbon payments enabled them to change practices, how can we distinguish between genuine financial necessity and convenient post-hoc justification? This question acknowledges human psychology and economic complexity, recognising that people's explanations for their decisions aren't always reliable evidence of causation, which is crucial for rigorous policy evaluation.
What would happen if we designed environmental policies around what needs to happen rather than what's currently considered additional? This question challenges the entire framework of additionality by asking us to start from ecological necessity rather than market logic, potentially revealing more effective approaches to environmental problems.
How can we evaluate whether a carbon offset project delivers real climate benefits without getting lost in technical measurement debates? This question focuses sceptical attention on outcomes rather than process, helping readers develop practical skills for assessing environmental claims without requiring expertise in soil science or carbon accounting.
If soil carbon practices improve farming profitability and environmental outcomes, why aren't they already universal? This question exposes the real barriers to sustainable agriculture—which might include knowledge gaps, upfront costs, or institutional constraints—rather than assuming financial incentives are always the missing piece.
In the next issue
Three Questions That Transform Environmental Paralysis Into Action
What if the difference between productive environmental dialogue and frustrating deadlock comes down to asking better questions?
Next week, we'll share a simple three-step framework that consistently cuts through the usual response of "we need more research" to reveal actionable solutions hiding in plain sight.
Find conversation changers that work in university seminars, community meetings, and policy discussions… even around the barbecue on a lazy summer afternoon.
Master the art of moving from confusion to clarity.
I'll be honest—this isn't the fastest way to build an audience. Nuanced analysis doesn't generate the outrage clicks that simple answers do… or cute cat pictures.
But complexity deserves respect, and environmental challenges deserve our sharpest thinking.
If this approach resonates with your own experience of wrestling with difficult questions, I'm truly thankful.
Your contribution supports independent analysis that refuses to oversimplify.