Kelp’s role in carbon sequestration

Source: NOAA, Thriving Kelp forests help remove carbon dioxide from the atmosphere

In the title alone there are at least three words that can be seen as “climate jargon,” but if you’re reading this, we’ll assume you have some knowledge of what you are digging into. But if you are starting from scratch, let’s start with kelp. 

Kelp is similar to seaweed in that it is an underwater plant found in the ocean, but unlike seaweed, it grows incredibly fast – up to 18 inches a day – and in clusters like a forest. Kelp offers a habitat and protection for many species from fish to otters and can be found all over the world in cool waters right off the coasts.

When it comes to carbon sequestration, their fast growth is what makes kelp so attractive. Let’s find out why.

Excess atmospheric carbon

Source: NOAA, Chart from Mauna Loa Observatory showcasing the increasing concentration of atmospheric carbon dioxide from 1960-2020

Carbon dioxide (CO2) is a naturally occurring part of the atmosphere, it helps warm the world and is what plants “eat” to grow. But when fuels like gas are burned off, it emits CO2 as pollution. It’s pollution because unnatural chemicals are being burned off as well and because this extra CO2 throws off the ideal balance within the atmosphere.

If it is not removed by plants, CO2 can last in the atmosphere for over 100 years – and every single day we are adding billions of tons of CO2 to the atmosphere with much of it unable to be absorbed. 

We’re in this dilemma because while we continue to emit more CO2 we are actively removing natural environments like forests that act as CO2 “vacuums” by removing the CO2 from the air to fuel their growth.

What is carbon sequestration?

Carbon sequestration is a more scientific term for CO2 “vacuum” and it can be anything that removes and stores CO2 from the atmosphere. This can range from kelp, which feeds on CO2 and stores this carbon until it either dies or is eaten, to machines that remove CO2 from the atmosphere and store it in rocks. 

The goal of these methods is to remove the carbon and store it for hundreds, if not thousands of years so that it cannot continue to warm the planet. 

How does kelp help sequester carbon?

As we noted, kelp grows quickly. To do this, it absorbs carbon via photosynthesis and this CO2 is then stored within the kelps tissue. The CO2 stays there until it is either eaten by another animal or the kelp dies and breaks down, becoming detritus on the sea floor, where the CO2 stays forever. 

Potential drawbacks to kelp farming 

One of the largest challenges to kelp farming, and other natural options like trees, is that if an animal eats the kelp, that carbon is considered emitted. Meaning, that it is no longer being stored, it does go into the atmosphere. The act of cutting down a living plant, from broccoli to trees, emits part of the carbon it is storing. 

To decrease the amount of carbon emitted, kelp farms can be monitored and then purposefully cut and moved to deeper waters, sinking to the bottom to allow the carbon to remain on the sea floor. 

Another potential use for kelp is that it can be used as a biofuel, like sustainable aviation fuel to power planes. Carbon would be emitted, but it would be significantly less than traditional fossil fuels. Seaweed can also be used to create biodegradable “plastic.”

So even if carbon is not sequestered in kelp forever, other uses for kelp make it worthwhile to farm.

Opportunities in kelp space 

There are not many kelp sequestration opportunities available because it is still a relatively new field. There are kelp and seaweed farms all over the world that grow and harvest kelp for food or cosmetic use, but there are not as many operations that exist just to store carbon. 

One of the best ways to do this is to keep natural kelp habitats intact by making them marine sanctuaries and allowing them to thrive undisturbed. But, as kelp-focused roles pop up in Europe, Jobs for Planet will be sure to post them!