Blue Carbon: Why are we destroying some of the most useful tools to combat global warming?

When thinking of ways to combat global warming, often we look to new and advanced technologies. However, some of the most effective methods use fairly simple and natural means to tackle the looming problem of global warming.

One such method is carbon sequestration. Carbon dioxide, being the most commonly produced greenhouse gas, is relatively abundant in the atmosphere. Carbon sequestration involves capturing the CO₂ in the atmosphere and storing it, effectively locking it away in the absorbing substance and reducing the amount remaining in the atmosphere. This can be achieved in various ways, for example carbon sequestration can occur naturally in plants and trees (via photosynthesis), in rocks and oceans, and even using technology to sequester carbon.⁽²⁾

Using the ocean to store carbon dioxide can be incredibly effective at storing large amounts of CO₂ and keeping it locked away for a very long time. However, it should be noted that storing  our CO₂ in the ocean isn’t without its issues; it does remove harmful CO₂ from atmosphere, though increased CO₂ increases the acidity of the ocean and can have an effect on ocean life, which we are already seeing.⁽³⁾ Despite this, they are still useful. ‘Blue carbon systems’ are coastal and ocean environments that sequester carbon, such as mangroves, salt marshes and sea grass. These systems have incredible carbon-capturing power and are able to capture carbon at a much greater rate than other systems, even tropical forests⁽⁴⁾. These systems can thus be vital in our efforts to reduce our emissions and become ‘carbon neutral’. Particularly, seagrass and kelp can be extremely useful. Seagrasses cover less than 0.2% of the ocean floor, yet they store around 10% of the carbon buried in the oceans each year⁽¹⁾.

Surely we should therefore be doing everything we can to protect and nurture these important environments? As it turns out however, these environments are among the most threatened. Due to human activities such as coastal development and trawling, we are losing these ecosystems at a rate of around 1-2% per year, and some have lost almost half their historical global coverage^{(1, 5)}.

With their immense ability to capture carbon, it is devastating that this is the case. Since the carbon that is captured by these systems is stored within it or in the soil below, once they are destroyed, the carbon has nowhere to go but to escape back into the atmosphere. This is not a small impact either. Since these ecosystems are so effective at capturing large amounts of carbon, all of their hard work is reversed as they then become significant sources of greenhouse gases themselves (up to 19% of tropical deforestation emissions globally)^{(1, 5)}.

Clearly, it is of utmost importance that we reinstate these systems as they are so useful in sequestering carbon. In a recent report published by Natural England⁽⁶⁾, (the government’s adviser for the natural environment⁽⁷⁾) the importance of the blue carbon systems were highlighted using research carried out by Dr Ray Ward of Brighton University⁽⁴⁾. Dr Ward is also on the scientific advisory panel for the Sussex Kelp Restoration Project (called ‘Help our Kelp’). This project aims to restore the large kelp forest that once stretched along the south coast of England, which 96% of has now been lost since 1987 due to human trawling, storm damage and other measures.^{(8, 9)}This destruction can be seen in the two images below⁽⁸⁾.

In March of this year, a byelaw was passed after campaigning with the support of Sir David Attenborough which means trawling along the Sussex coast, where the large kelp forest used to live, is now banned^{(8, 10)}. This is an extremely important step as this allows the first kelp restoration project in the UK to begin rebuilding the coastal area. Research is now being carried out to help understand and support the restoration of the kelp forest, while raising awareness of kelp’s importance. Currently, environmental DNA (DNA which is released by organisms into the environment⁽¹¹⁾) is being collected to help understand the baseline biodiversity and to enable the researchers to track the change in biodiversity as the kelp is restored⁽¹⁰⁾. This is because not only is kelp beneficial for climate change, but it is great for the marine environment. It provides habitats and breeding grounds for a vast number of different species of fish and ocean animals, allowing them to thrive⁽⁹⁾.

Below, see a video narrated by Sir David Attenborough highlighting the importance of kelp forests⁽⁸⁾.

It is hoped that, once the kelp is restored and the benefits are clearly seen, awareness will be raised as to the benefits of kelp and other blue carbon systems, not only for the environment but also economically and socially⁽¹⁰⁾. With increased recognition, other areas may stop destroying these vital environments and allow them to thrive. Sir Attenborough himself claimed that the passing of the byelaw was a “landmark decision”⁽¹⁰⁾. Hopefully governments around the globe will take note and begin to enact more policies to benefit the planet and reduce global warming and climate change.

Ideally, to further help combat global warming, we would plant large industrial style kelp farms across the globe. However, this is not very feasible. The technology is not yet available to grow and plant large kelp farms out at sea. Also, kelp and other seaweeds have a surprisingly large number of uses resulting in them being very high demand materials. For example adding seaweed to livestock feed can reduce their greenhouse gas emissions, of which they produce a significant amount, by up to 70%⁽¹²⁾. As a result, it is not economically favourable at this time to invest in the technology needed to begin planting and burying large scale kelp farms.

Research is however being done investigating kelp reforestation and new methods which are both cheaper and easier to implement are being discovered^{(13, 14)}. Hopefully in the future kelp’s potential will be realised globally and more will be done to utilise this powerful plant to combat global warming.

 

Author: Oliver Pearce

 

 

 

 

 

 

References:

1. The Blue Carbon Initiative. Blue Carbon 2019 [Available from: https://www.thebluecarboninitiative.org/
2. UC Davis. Biological Carbon Sequestration [Available from: https://climatechange.ucdavis.edu/science/carbon-sequestration/biological/.
3. Hume D. Ocean Storage of CO₂2018 31/07/2021. Available from: https://www.maritime-executive.com/features/ocean-storage-of-co2.
4. Researcher provides vital input to major report on natural carbon capture [press release]. Brighton University, 30/04/2021 2021.
5. Luisetti T. Some countries donate blue carbon. Nature Climate Change. 2021.
6. Natural England. Carbon Storage and Sequestration by Habitat 2021. In: Environment, editor. 2021.
7. gov.uk. Natural England [Available from: https://www.gov.uk/government/organisations/natural-england/about.
8. Blue Marine Foundation. Sussex Kelp 2020 [Available from: https://www.bluemarinefoundation.com/projects/sussex-kelp/.
9. Sussex Inshore Fisheries and Conservation Authority. Kelp 2021 [Available from: https://www.sussex-ifca.gov.uk/kelp.
10. Sussex Wildlife Trust. Sussex Kelp Restoration Project 2021 [Available from: https://www.sussex-ifca.gov.uk/kelp.
11. Freshwater Habitats Trust. What is eDNA? [Available from: https://freshwaterhabitats.org.uk/projects/edna/edna/.
12. Woody T. Seaweed ‘forests’ can help fight climate change2019; (Environment and Conservation). Available from: https://www.nationalgeographic.co.uk/environment-and-conservation/2019/08/seaweed-forests-can-help-fight-climate-change.
13. Fredriksen S, Filbee-Dexter K, Norderhaug KM, Steen H, Bodvin T, Coleman MA, et al. Green gravel: a novel restoration tool to combat kelp forest decline. Scientific Reports. 2020;10(1):3983.
14. Layton C, Coleman MA, Marzinelli EM, Steinberg PD, Swearer SE, Vergés A, et al. Kelp Forest Restoration in Australia. Frontiers in Marine Science. 2020;7(74).