Can’t I Just Write a Check

Can’t I simply purchase carbon offsets to cancel out the greenhouse gas emissions my actions cause? Many carbon offsets have serious issues that impact the answer.

I was enticed to pay for carbon offsets for my natural gas use and signed up to pay a monthly stipend for the Enbridge GreenTherm program. But when I examined the offsets more closely, I realized that the math does not really add up. I withdrew from the program and dug in to better understand offset products that I’ve seen offered by my natural gas utility, my electric utility and by airlines. What I found was not encouraging.

It is nearly impossible to live within a developed economy and not produce any greenhouse gas emissions. Changing our diet can cut a ton of carbon dioxide equivalent (CO2e) emissions per year by eating no beef and less meat (or simply no meat, dairy, eggs). Yet even a low-emissions diet causes over a ton of CO2e per person per year. And sometimes it is difficult to completely avoid air travel if your family lives in another part of the country or world. Another additional ton of emissions.

One option to balance out these emissions is to buy a carbon offset which represents the reduction, avoidance, or removal of greenhouse gas emissions and match these offsets with the extra emissions we are causing. The carbon offsets we can purchase are often linked to projects in specific places that reduce emissions and sold to compensate for emissions in a different place. Carbon offsets are frequently bought either by

• corporations or companies that have made a commitment to reduce their greenhouse gas emissions or market their net zero emissions to their consumers, or

• governments that have passed laws or agreed to reduce their emissions but can not meet the requirements from actual emissions reductions within their boundaries.

But people also buy these offset credits. And some companies specifically offer these offsets as a way to help consumers that are concerned about climate change rationalize using their products. One example is the Enbridge Gas GreenTherm program to offset emissions from burning natural gas in our home or business.

Costs for these products can range from $20 per ton CO2e to over $1,000 per ton of CO2e avoided or removed. On the higher end of this price range, an individual can pay $400 to over $1,000 per ton CO2e for actual isolation of carbon atoms where they will be sequestered for thousands of years, leading to a removal of CO2 in the atmosphere. Capturing carbon atoms and keeping them from cycling back into the atmosphere as carbon dioxide is frequently referred to as carbon dioxide removal or CDR.

On the lower end of the price range, an individual might pay $20 to a few hundred dollars per ton CO2e for a carbon offset, where the buyer pays for the reduction, avoidance or removal of a unit of greenhouse gas emissions by different entities to counterbalance a unit of emissions by the person or organization that purchased the credit. Carbon offsets are commonly subject to rules and environmental integrity criteria which I’ll discuss below. When examined closely, many offsets appear to fail to meet some of these criteria.

As an example, an individual might pay to offset the emissions from burning natural gas to heat their home and water. Enbridge supplies my natural gas and offers offsets for purchase through a program they branded GreenTherms. Enbridge states that “a typical residential customer can offset their entire natural gas carbon footprint each month by purchasing four $3 blocks a month, or $12 total a month, achieving net zero carbon emissions from their monthly natural gas usage.” The actual accounting for this program is not disclosed on any page I can find at Enbridge, but when the program was introduced by a previous owner of my gas distribution, the price appears to have been equivalent to $3 per 12.5 therms of natural gas which is equivalent to $45 per ton of CO2e. But the typical purchaser would not know they were paying $45 per ton of CO2e offset. In North Carolina GreenTherms currently support four different landfill gas capture and combustion projects, including the landfill that my trash goes to, the Buncombe County Landfill.

Problems with carbon offsets have been identified and extensively discussed. A solid overview of the problem of carbon offsets was published in the 2025 “Annual Review of Environment and Resources: Are Carbon Offsets Fixable?” by Joseph Romm, Stephen Lezak and Amna Alshamsi (DOI 10.1146/annurev-environ-112823-064813).

Some corporations are being forced to admit that many of these offset credits are not reliable. A few years ago, Delta Airlines claimed that their flights were carbon neutral by relying on offset credits, then Delta reversed this decision after Delta was sued. The lawsuit against Delta claimed that the benefits from the offsets were likely temporary and would have happened even without the firm’s investment (AP), issues of permanence and additionality discussed below.

Offsets are commonly subject to rules and environmental integrity criteria intended to ensure that the offsets achieve their stated mitigation outcome. In this post, I’ll explore four of these criteria and explore how they are frequently not met:

• Avoidance of double counting

• Additionality

• Leakage

• Permanence

Next week I’ll examine carbon dioxide removal (CDR) which is typically 10 times more expensive than a traditional carbon offset but passes more of these criteria.

Avoidance of Double Counting

If an organization makes an effort to reduce their greenhouse gas emissions and sells the carbon offset, the carbon offset only has value if no one else is taking credit for the specific reduction in emissions.

Let’s examine the offset of capturing and destroying the methane produced at my local Buncombe County landfill I mentioned above which is used as an offset for burning natural gas in my home. In a landfill, waste organic material is covered and naturally breaks down in the absence of air releasing methane and other gases. For this carbon offset, the methane (natural gas) is captured and destroyed (burned), and in the process of burning the methane, electricity is generated which is put on the grid. The county I live in chose to sell the credit for the capture and destruction of methane that the landfill creates. The people who enroll in the GreenTherm program through Enbridge write a check to believe they are the ones capturing and destroying the methane gas - a way to justify their own emission of carbon dioxide from burning the natural gas that Enbridge delivers to their homes or businesses.

However, the county where I live also takes credit for this. The solid waste manager for my county told a local reporter that the county “voluntarily invests in landfill gas collection and control through its landfill gas-to-energy facility.” But this is not really the case. Once the county sold the carbon offset, they could only say that some unnamed investors came in and paid the county to destroy this methane. But the cost of the offsets does not cover the full cost of the project, so even this statement would be false.

Let’s examine the full consequences of this double counting regarding who reduced these emissions. In my county, residents (and businesses) can dispose of their trash in a local landfill that creates methane gas as the trash degrades, and residents can also burn natural gas to heat their homes and water. Since their landfill captures the methane and destroys it, they can be proud that the emissions they cause by putting waste in their landfill are significantly reduced; and at the same time they can buy a carbon offset from the landfill to offset their emissions from burning natural gas in their home so - at that point these homeowners (or businesses) hold that their home emissions are zeroed out. And yet they are actually still emitting carbon dioxide from burning the natural gas to heat their home and water. The people who bought the offsets have simply helped fund a project that cuts the emissions from the landfill where they place their trash - where they would also be responsible for the emissions anyway.

This double counting is also rather easy to spot when examining carbon offsets that are used to generate low emission electricity. Renewable energy credits (RECs) are a special type of credits that are similar to a carbon offset. The purchaser of a renewable energy credit buys the environmental and social attributes of one megawatt-hour of electricity generated from a renewable source of electricity like wind or solar power. And, again, my local electric utility offers a program to offset the emissions from my electric bill using renewable energy credits (Duke Energy’s Go Renewable program.)

To understand the issue, imagine calculating the emission from a home that uses electricity in a state with lots of wind power, we’ll use Iowa as an example. The Energy Information Agency informs the person in Iowa how much CO2e is generated for a kWh of electricity they use in Iowa (699 lbs carbon dioxide per MWh), the statistics are based on the electric generation for their portion of the electric grid. While someone else may have bought the “environmental attribute” or emission reduction from their wind energy, a person (or business) in Iowa will still calculate their emissions as if their electricity has a lower emission profile (lower lbs CO2 per MWh or lower tons CO2e per kWh). So both the end user and the person who bought the renewable energy credit (REC) are taking credit for the same low-emission wind energy powering the grid in Iowa.

It is important to understand that the price of these carbon offsets or renewable energy credits do not cover the cost of the emission reduction projects. The cost of the offsets can help cover some of the costs, but the price is not based on the total cost of the project, only the ability to get people to buy the offsets or RECs in an open market where these people gain no advantage other than claiming they have lowered emissions in some way. And all the while other people continue to claim they are emitting less after the offset or renewable energy credit is purchased.

The impact of carbon offsets being double counted go beyond simply reducing the true value of the offsets. These offsets remove the motivation to accomplish the actual emission reductions for those emissions that are offset. They caused the buyer of the offset to believe that they are not emitting greenhouse gases even though they continue to do so. These offsets falsely justify continued emissions from the person who buys them.

Additionality

A carbon offset is only supposed to be created if the reduction in emissions is new (additional) and would not have happened if the credit was not purchased. Often, if there was no payment for the offset, the change in emissions would not have been as significant as the carbon offset assumed. Maybe even the entire project would have proceeded any way and the lack of the offset would not have changed the total emissions at all.

Let’s return to the example of buying a carbon offset for the capture and destruction of methane being emitted from my county landfill. The county I live in (Buncombe County, NC) committed to reduce greenhouse gas emissions and to rely on 100% renewable energy for County operations. If there were no offset credits, a likely baseline scenario is that the County still would have taken action to capture and destroy the methane being emitted from the landfill, they would have simply been required to find a way to make up some additional funding. If the county would have acted to reduce the methane emissions even without the sale of carbon offsets, then payment for the offset does not create an additional reduction in greenhouse gas emissions and the offsets should not be certified nor sold.

Many lower cost carbon offsets are for the preservation of forest land. These offset credits may account for the different land use emissions (or carbon sequestration) between a plot of land continuing to grow a forest or the same plot being logged and maybe converted to farmland. However, if the offset was never sold, another alternative is that the trees would have remained on the property for some period of time, maybe even a long period of time. If this were the case, again, the carbon offset sold does not cause an additional reduction in greenhouse gas emissions and the offset should not be certified nor sold. This issue is common for offsets sold to address deforestation or improved forest management.

Leakage

Leakage occurs when the emissions reduction that is sold as a carbon offset is simply shifted from the project boundary to an area outside the project boundary. When this happens, there is no real reduction in emissions. This is a frequent critique of projects related to reducing deforestation - a category in a United Nations framework referred to as Reducing Emissions from Deforestation and Forest Degradation (REDD+). If the demand for timber is not changed, and the sale of offset credits simply shifts which sections of a forest are logged, then no real emissions reductions occur even when the offset is sold.

For forestry projects, appropriate losses to leakage are hard to measure but are estimated at 80% or higher.

Permanence

If carbon emissions are avoided for a single year, that is different than if emissions are avoided for a decade or for 100 years. On the extreme end, many carbon dioxide removal projects costing $400 to over $1,000 per ton CO2e removed isolate the carbon from the atmosphere for durations of thousands of years or longer. On the other extreme, many nature based solutions such as forest preservation have both a shorter duration and less control on the permanence. Concerns with the duration of forestry based projects have risen as climate change has worsened issues such as pest control, drought and wildfires which directly threaten the trees.

A 2021 study of organizations planting trees world-wide stated that “there was little to no discussion of monitoring across organizations, so the number of trees that actually survive is likely much lower. Only 18% of the organizations (n = 32) mentioned monitoring at all, and of these, only eight measured survival rates and/or ensured some level of maintenance post-planting.”

Carbon Dioxide Removal (CDR)

Next week I’ll explore the longer term benefits of carbon dioxide removal (CDR). There are now opportunities to pay for the long-term removal of carbon from the biosphere and atmosphere - isolating the carbon molecules so the carbon will not return to the atmosphere as carbon dioxide. The cost of commercial carbon dioxide removal you can pay for starts around $400 per ton CO2e removed and extends up over $1,000 per ton CO2e removed. Even in this market place, when you buy a ton of carbon dioxide removal there are some issues you should understand before paying for the offset.

Personal Emissions Reductions

Exploring carbon offsets has solidified my decision to focus on reducing the emissions my purchases and lifestyle cause and changing my behavior to reduce my emissions – that is the basis behind co2mmit. As I get to areas that are harder and harder to further reduce my emissions, I may rely on carbon dioxide removal. True carbon dioxide removal credits at $500 to $1,000 per ton of CO2 for my full emissions might be a good way to financially motivate further action.

And, at the same time, I will continue to support organizations that help people that are not able to afford the investments to reduce their utility bills and emissions.

I will also support and work for policy and legal changes to reduce emissions. But I will not wait for a law to tell me to lower my emissions when I can already make the choices required to bring my emissions down today. With no new law and with the existing technology and available products and services, I can lower my emissions significantly through focused, intentional action.

Jim