This article is a brief description of carbon offsetting through projects related to blue carbon, which are nature-based projects related to aquatic ecosystems. It is for someone intending to offset their carbon footprint, providing the basics for how these projects achieve carbon offsetting, what carbon accreditation auditors look at when evaluating them, and issues commonly associated with them.

For preparatory reading, and links to other articles in this Carbon Offsetting series:


Carbon Offsetting & Net Zero Emissions

Since the global warming phenomenon was first confirmed in the 1990s, the need to scale back greenhouse gas emissions has been known.

Greenhouse gases have increased at an unprecedented rate in planetary history, driven by mankind’s burning of fossil fuels within a relatively short period of time. The increased heat trapped by the added greenhouse gases have begun to change the balance of climate systems, some of which lead to the release of even more greenhouse gases (e.g. forest fires, permafrost melts).

In 2015, the Paris Agreement saw the nations of the world agree that global warming needs to be kept below 2 degrees above pre-industrial global temperatures (aiming for no more than 1.5 degrees to avert the worst effects of climate change to vulnerable nations).

Net zero carbon emissions is not about that.

You may notice a growing number of companies pledging to be ‘net zero’ or have ‘net neutral’ carbon emissions. Invariably this will involve changing the way their businesses operate so that they emit less carbon. And, if there are any carbon emissions left over, they have to be offset.

However, without needing to be particularly good in math, you would realise that even if all businesses are net neutral from now on, we would still not be in carbon balance. The greenhouse gases already in the atmosphere now will continue to heat the earth, and climate change that is already underway will release other greenhouse gases from natural reserves.

So this is why I say upfront that going net zero is not about solving climate change. Additional things have to be done over and above that. Going net zero is about not making the problem worse, so that it isn’t harder and harder to solve.

Carbon offsetting verification standards

Carbon projects rely on carbon accounting to qualify as carbon offsetting. (Jargon cheat sheet article link is at the top). Like financial accounting, you need audits to make sure the carbon accounting is honest. Unlike financial accounting, which has been around for longer, carbon accounting is still being tweaked, since is it still a relatively new discipline. That this is still going on, does not mean that carbon accounting isn’t trustworthy, or that it isn’t essential.

Carbon projects may be fully dedicated to a company intending to meet net neutral targets (e.g. Qantas’ reforestation project), or generate credits which can be bought by individuals, like you and I. The latter are usually managed by carbon offsetting service providers, such as Terrapass.

We can rely on audits carried out by the service providers to be assured that projects are managed to standards submitted to the United Nations Framework Convention on Climate Change (UNFCCC). Examples include the Gold Standard, and the Verified Carbon Standard.


Blue Carbon Offsetting Projects

OK, with the context out of the way, now on to the project type. This article will cover blue carbon projects and touch on the ones that now qualify for carbon credit funding.

What are blue carbon ecosystems?

When we think about nature-based carbon storage, we think of forests. After all, most cultures are continental.

However, countries with long shorelines are more familiar with coastal ecosystems. Despite existing only within a narrow strip of coastal land, these ecosystems range widely from forest (mangroves) to the ‘grasslands’ of salt marsh. Offshore, there are yet more ecosystems such as seagrass and kelp meadows.

Like forests, all of these marine ecosystems also capture carbon. It is now suspected that many of them also store carbon. The term ‘blue carbon’ is used to distinguish them from carbon stored by terrestrial ecosystems.

Tanjung Piai mangrove edge, Malaysia

What is the difference between blue carbon and terrestrial stored carbon?

Why is the distinction necessary?

While part of it is to draw attention to the potential of these undervalued ecosystems, there’s also a more practical reason. Coastal and marine ecosystems harbour different processes that influence the way carbon cycles through, and whether it gets stored or emitted. Additionally, carbon enters the ecosystem in more ways. Blue carbon ecosystems absorb carbon dioxide in the form of gas during photosynthesis in the way that terrestrial forests would. But carbon also enters the ecosystem through water flows. Therefore, blue carbon balance is more dynamic than forests.

How do blue carbon ecosystems combat climate change?

Up until recently, the mainstream view was that coastal ecosystems are not important in climate action at all. In fact, wetlands were thought to be carbon sources, because the waterlogged conditions favour anaerobic degradation, which generates methane. Methane, of course, is an even more potent greenhouse gas than carbon dioxide.

However, research in recent years have discovered that coastal ecosystems actually store large quantities of carbon. For example, mangroves can store between 3-5 times more carbon than tropical forests, and can continue doing so for longer. Protecting and restoring mangrove ecosystems can mitigate 108 million metric tonnes of CO2e per year.

The reason for this is because mangroves do not just store carbon in woody biomass. They also trap sediment from river flows which carry carbon from all the ecosystems upstream. The carbon-laden sediment then stays in storage for hundreds of years. This means, unlike terrestrial forests, mangrove forests can continue to store carbon even after the forest itself is mature and respirates in equilibrium.

Coastal ecosystems are important for climate action for another reason. Existing coastal ecosystems have been storing carbon in this way for a long time. They hold more carbon in sediment and soils, than forests. Therefore, if these ecosystems are lost through land use conversion, all of that carbon will re-enter the atmosphere.

Per acre, coastal ecosystem degradation has a bigger climate impact than deforestation. Its protection is critical to limit global warming. Today, degraded coastal ecosystems release 1.02 billion tonnes of CO2 annually. Protection can reverse this to storage. Yet, coastal ecosystems continue to be lost.

salt marsh stock photo

Why is there no data for non-mangrove ecosystems?

You may have noticed that all of the statistics so far, are for mangroves. There is some data for other coastal ecosystems such as salt marshes and seagrass. However, they are not yet as well studied. Even though there is potential for carbon storage, estimating how much happens still requires some work. Even for mangroves, how to estimate the storage of carbon that comes into the ecosystem is still in progress.

Are there blue carbon offsetting projects?

Last year, I would have answered a clear no. However, just this year Verra submitted a methodology to the UNFCCC to qualify and audit blue carbon projects.

At the moment, existing methodologies only cover restoration of degraded mangroves, and small scale wetlands recovery. These methodologies are conservative, since they only consider carbon captured through tree growth. This is because in issuing carbon credits, certainty for what the credit means is more important. Remember that carbon offsetting is really about putting climate action into an accounting framework, so that we can better manage it.

When the science is more certain about storage of carbon inflows, methodologies would probably be updated to account for it. It could be soon; the Blue Carbon Initiative have issued a manual that provides guidance for how to consider this for mangroves, salt marshes, and seagrass.


Local exploring the long history of China with present-day Indonesia, in the form of Chinese graves in Semarang from Ming Dynasty.

https://t.co/VnFKK1G9oO

Here in #Vanuatu, main concern is about reviving tourism. There’s a plane shortage due to lease arrears, hence the unreliable domestic transfers. But w/o those planes, tourism on the islands would die.

I say: go to the #Pacific anyway, but be very flexible.

#TravelNews


Clean Development Mechanism (CDM) methodologies for blue carbon

Due to the developing state of knowledge, most blue ecosystem projects do not qualify as carbon offsetting projects. This is not because they do not store carbon. It’s because a carbon offsetting project gets to earn carbon credits. So you have to be able to calculate how much carbon was removed – and stayed removed – by the ecosystem. And that’s the part that’s missing or incomplete for now.

At this time, it is possible to have a genuine accredited mangrove or wetland project. However, the storage estimates per credit sold would definitely be less than the real storage, because prevailing methodologies simply don’t count the major way that these ecosystems can store carbon.

At the moment, they are basically the same as would apply to a reforestation or afforestation carbon offsetting project. The additional considerations are on what kind of land would or wouldn’t qualify. Largely this is related to hydrology changes due to the project. For example, large scale restoration of degraded mangroves must not include more than 10% of non-mangrove species, unless it will not impair coastal hydrology.

The downside of this situation is that your blue carbon offset is probably worth more than the project can tell you. The upside is that if you did your carbon offset via a blue carbon project, you’re really net positive rather than just neutral. You just don’t know by how much, that’s all.

Tanjung Piai mangrove forest

What are potential future blue carbon projects?

At the moment, the blue carbon ecosystems that we focus on are semi-land, semi-marine. This is because these ecosystems are similar to forests and grassland.

However, blue carbon potential is greater than that. There are fully marine ecosystems that may also be significant carbon storage. After all, more than 80% of the carbon cycle passes through the oceans. Here are some possible future blue carbon projects.

Seagrass meadows

Seagrass occupies less than 0.2% of the ocean, yet they store 10% of carbon buried in the ocean every year. Its restoration is also attractive from a Biodiversity Crisis perspective, providing habitat and feeding grounds for various marine species.

Algae cultivation & kelp forests

Algae such as seaweed and kelp are another kind of photosynthesising life form. Therefore, they will also absorb carbon through natural processes. Kelp can grow into underwater forests that constitute a kind of ecosystem, providing habitat and shore protection benefits. On the other hand, seaweed cultivation can scale up as an agricultural activity.

Boardwalk path through the mangrove section in Cairns Botanical Gardens

The role of blue carbon in Small Island Developing States (SIDS)

There is another reason that blue carbon is special. Most carbon offsetting projects and green financing relate to activities more commonly carried out in larger or continental states. Most renewable energy projects, even if offshore, are only viable if they supply a large land demand. Agricultural projects and reforestation are all related to continental countries. Even REDD+ funding would only go to developing countries that have significant forests.

But there is a category of states that are missing out. Small Island Developing States (SIDS) are nations with no significant land mass, but a lot of sea. They are the most exposed to global warming. Some islands would be submerged with sea level rise, their people becoming refugees. Most are still developing, and have less technology to mitigate the consequences.

But, if coastal and marine ecosystems can in fact slow down climate change, carbon credit funding could be an additional flow of finance to help SIDS respond. It would also be funding that does not have ‘aid’ connotations, which probably means a great deal. As someone who is also from the developing world, I would guess so.

Environmental justice is practical: it opens up more solutions.

Issues of environmental justice are unique for SIDS even relative to the rest of the developing world, as you can see. On the one hand, they are the most at risk, yet probably contributed the least to the problem.

But on the other hand, if we view SIDS only in this context, it would overlook the potential of their unique worldview. For technology may now allow us to go fully oceanic as a form of climate adaptation. And the worldview of SIDS can turn it into a new era for all humankind.

Should I Offset My Carbon Footprint with a Blue Carbon Project? | Carbon Offsetting series article on sustainable travel blog Teja on the Horizon | Cairns mangrove wetlands

Further reading:


An important part of the Paris Agreement is recognition that countries must have the freedom to choose the combination of methods for how they meet their climate ambitions, because each nation has vastly differing circumstances. A solution that doesn’t make sense to one country – however large and influential – may be perfect for another. Can blue carbon solutions be how your country meets its climate commitments?

Article explaining how to understand blue carbon offsetting projects

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