Carbon Offsetting Cheat Sheet - How to Understand the Terms
The purpose of this article is to serve as a quick primer of terms used in carbon offsetting and global warming discussions. Think of it as a 'cheat sheet' to help you understand carbon offsetting well enough to follow the other (upcoming) articles in this Carbon Offsetting series, or elsewhere.
This will be a live article. I plan to update it as I discover additional terms that seem useful to explain, or if I think of better ways to illustrate these concepts. If you are an artist or some kind of visual communicator who can think of creative ways to have these concepts come across more intuitively to regular people, please get in touch.
- What does a carbon offset mean?
- Why is it called 'carbon' emissions?
- What is a carbon credit?
- What is the difference between carbon capture and carbon sequestration?
What does a carbon offset mean?
In order to understand carbon offsetting, first you need to understand global warming. Global warming refers to the increase of the sun's heat energy in the earth's atmosphere.
In its long history, the earth has gone through periods of highs and lows in the radiation it gets from the sun (i.e. 'solar radiation'), as well as other events that make the atmosphere worse or better at trapping the sun's heat. These include carbon dioxide accumulation, volcanic activity, and formation of carbon-fixing ecosystems (like, forests). But the warming in recent times is unusual because its speed is driven by the rate of fossil fuel burning by humans.
To put it another way, human beings are releasing carbon dioxide into the atmosphere (i.e. 'carbon emissions') faster than the ability of other systems on the planet to re-absorb it. The excess carbon dioxide hanging around is a problem because it has the effect of trapping solar radiation on earth, i.e. a 'greenhouse gas'. (It's called a greenhouse gas because it makes the earth like a greenhouse!)
Sunlight can reach the earth's surface as light waves. But it's mostly then released into space as heat radiation, which can be blocked by greenhouse gases. This is not a bad thing in itself. It is what makes Earth warm and habitable for us in the first place.
The problem is when too much of it starts to change the climate systems that ecosystems have evolved to rely on (i.e. 'climate change'). It's even worse when the rate of change is so fast that plants and animals in the ecosystems have no time to adapt or evolve.
What does carbon offsetting do?
To solve this problem, we have to constrain - or at least slow down - the rate of change. We need to drastically reduce our carbon emissions rate, and increase the planet's ability to re-absorb past and current emissions that are overbalanced.
Carbon offsetting is about quantifying how much greenhouse gas is released from an activity such as burning fuel for energy (i.e. 'calculating a carbon footprint'), and then increasing carbon absorption capacity somewhere on earth by the same amount. The activity is then considered 'carbon neutral' or 'net neutral'. (If it captures more greenhouse gas than it releases, then it is 'carbon positive'.)
What carbon offsetting doesn't do.
What carbon offsetting doesn't do, is solve other environmental problems. Unless the carbon offsetting project coincidentally has such benefits, carbon offsetting is not an action directly related to efforts around problems of water scarcity, biodiversity, plastic pollution, etc.
That said, carbon offsetting projects bearing the Gold Standard do solve some additional issues (see section on accreditation programs below). This is so that we don't get in a situation where solving one environmental problem creates a different one.
Additionally, carbon offsetting is only about human-caused emissions. Climate change itself can cause additional carbon emissions from previously dormant storage. For example, consistently warm winters are causing permafrost melts which release previously trapped methane, a more potent greenhouse gas than carbon dioxide.
Carbon offsetting does not attempt to neutralise these emissions. These emissions, along with past emissions, are the reason why we have to emit less greenhouse gases overall. Carbon offsetting is not enough.
For why carbon offsetting is a thing that we need, even though it's not enough on its own, see this section in my first Carbon Offsetting article.
How do carbon offset projects remove carbon?
There are many ways to re-absorb carbon dioxide from the atmosphere.
Some projects seek to increase the natural ability of the planet to re-absorb carbon emissions. They do so by increasing the acreage of carbon-fixing ecosystems (or 'carbon sinks'), or ensuring their permanence. Examples include re-planting forests and protecting wetland habitats. These are called 'nature-based solutions'.
Some projects seek to help developing countries afford renewable power generation. Energy growth is projected to be highest in developing markets. Removing any cost difference between renewable power and conventional fossil fuels helps ensure that newly-built power generation is sustainable, and does not come with even more carbon emissions in the future.
Other projects seek to reduce or capture methane losses into the atmosphere. Examples include methane leaks from old landfills, as well as - no lie! - farts and burps from cows. Although present in smaller quantities compared to carbon dioxide, methane is better at trapping heat than carbon dioxide. Without carbon offsets, such research and infrastructure upgrades would often not be funded.
Aside from the more common methods, research and technology trials are also in progress to invent new ways of capturing greenhouse gases already in the atmosphere. At the moment we only have nature-based solutions for this. Eventually nature-based solutions will max out, but we will probably still need to remove more. This is why these efforts are important. Examples include 'carbon capture and storage' (CCS) and biochar.
Other articles in this series will cover the more common project types in greater detail. I will try to write them to help you understand the different carbon offsetting methods, well enough to be able to ask questions (work in progress).
Where do carbon offset projects take place?
They take place everywhere!
Because of the diversity of carbon offset methods, and the diversity of need and opportunity around the world, different projects have the most impact in different parts of the world.
For example, renewable power generation capacity projects usually takes place where there is growth in demand, plus cheap fossil fuels. (If fossil fuels were already expensive, the renewable energy project would probably happen anyway because it costs less).
Forest protection projects might take place in countries where deforestation threat is real, but also with sufficient rule of law. (Otherwise, a corrupt government can chop down the forest and the project can't honour the carbon offset you purchased).
CCS, on the other hand, might be installed at legacy power stations in countries where energy demand has plateaued. Where there's no demand for additional energy, it could be more expensive to replace existing power stations with a brand new one, compared to fitting old ones with CCS.
How do you buy a carbon offset?
The short answer is my article "2 Best Ways to Offset Your Carbon Emissions - Based on Personality!". In it, I guide you through two ways that you can buy offsets easily and with assurance that they're real.
There are two basic parts to assessing legitimacy. The first is whether the emissions reduction itself actually happens (like, in nature) and is additional. The second is whether the accounting part happens, to measure how much offset happened.
In my upcoming articles, I will describe the main types of carbon offsetting projects that you might come across independently, and how to get a basic understanding for whether they're likely to be legit.
Do I need to understand the carbon offsetting technology to participate?
No. You can participate in carbon offsetting as an individual even with a low level of knowledge.
Instead, you can rely on the verification of people who do have the knowledge. Look for the badge of at least one carbon accreditation program on the website of the carbon offsetting provider. Scroll down for examples.
Remember, there are two things that need to be verified in order for a carbon offsetting service to be credible.
First, there is some way to calculate your carbon footprint. For a detailed description for what a credible calculator looks like, see the first article in this Carbon Offsetting series.
And second, the project fulfils the legitimacy tests above: it can quantify how much emissions reduction is supposed to happen for a given amount that you're paying, and that it does really happen. If the project is verified under a carbon accreditation program, then you can participate without having the knowledge to validate it yourself.
Why is it called 'carbon' emissions?
I'll be honest with you. I'm not 100% sure.
When people talk about greenhouse gases in the context of climate change, they typically mean carbon dioxide. It's not because carbon dioxide has the worst effect, but because there's just way, way, too much of it, as a result of burning fossil fuels starting from the Industrial Age. Not only that, other greenhouse gases like methane (which is also a carbon-based gas) eventually break down to carbon dioxide in the atmosphere, adding still more.
I think it just became a shorthand for 'carbon dioxide emissions'. Especially since some of them start out as carbon monoxide or methane.
Why are carbon emissions measured in CO2e?
You might remember that CO2 is chemistry for carbon dioxide. So, what does the 'e' stand for?
Well, the 'e' means 'equivalent'. So, CO2e is 'carbon dioxide equivalent'. We use this unit because most of the greenhouse gas in the atmosphere is carbon dioxide, but we also want to measure other gases along with it.
CO2e is a measure of how much global warming effect a gas has, relative to carbon dioxide. In this way, we can compare the warming effect of a certain amount of methane to carbon dioxide using the same unit.
What is a carbon credit?
A carbon credit is basically a permit to emit (usually) one tonne of CO2e. The idea is for carbon emissions to come at a cost, because otherwise our modern economic system that is driving climate change doesn't swiftly transition to a more sustainable one. A common carbon pricing mechanism, on the other hand, uses the economic system itself to make low-carbon projects more financially attractive than projects which are carbon intensive.
In this way, polluting industries have the motivation to reduce their carbon emissions so that they can pay less for carbon credits. Or, they have to pay for carbon offset projects to earn the credits.
There is a starting quota of credits to kick off the whole mechanism, but this type of carbon credits is capped. So, a growing industry has to compete for a limited amount of credits, or figure out how to be less carbon intensive. Additionally, carbon offsetting projects can also generate carbon credits which can be traded in the same mechanism.
The more people join in to offset carbon emissions, the more carbon offset projects can happen because of demand for credits.
Conversely, if projects become limited for whatever reason, carbon credits increase in value, so it gets harder and more expensive for industries to just buy offsets, and are forced to find ways to decarbonise.
Major Carbon Accreditation Types
There are a few types of carbon accreditation programs. They range from the basic 'did the carbon offset really happen' kind of audit, to programs that take into consideration additional environmental or social benefits ('co-benefits') associated with the carbon offset project.
These are three that I've heard of, and that you'd probably come across.
Climate Action Reserve (CAR)
Climate Action Reserve (CAR) is a registry of carbon offset projects in North America. CAR assures that emissions reductions of its projects are real, additional (wouldn't have happened anyway without carbon credit funding), and permanent.
Verified Carbon Standard (VCS)
VCS is a voluntary greenhouse gas emissions reduction program managed by Verra. Like projects under CAR, emissions reduction of projects verified by VCS are assured to be real, additional, and permanent.
Gold Standard verification goes beyond just validating that the emissions reduction of the carbon offset project are real. This program tries to maximise the benefit of the project by lining up with suitable UN Sustainable Development Goals.
Therefore, projects assessed under the Gold Standard do something extra than just climate action (SDG #13). They might also contribute to other Sustainable Development Goals such as alleviating hunger (#2), or accelerate transition to sustainable cities (#11), or facilitate gender equality (#5).
What is the difference between carbon capture and carbon sequestration?
If you've come across these two terms, you might wonder if they're different, or interchangeable. I'm going to use a metaphor to explain how they're different. Otherwise, it gets complicated because there are many ways this can look like.
Basically, carbon capture is like when you divert water from a river into a canal. Now, if you were to irrigate a farm with the canal water, that's like carbon sequestration. The water can't go back to the river - at least not for a long while.
And what is carbon storage?
So after you irrigate the farm with the canal water, the plants take up the water and grow. Now the water is part of the plant matter. That's like carbon storage. The water isn't just water anymore; it's become part of something else. In order to get back to the river, it has to undergo additional processes to turn it back into water.
Do you have questions? What other terms do you think I should add? Comment below!