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Greenhouse gas removal
Our work on greenhouse gas removal is currently focused on four projects
Marine Biomass Regeneration:
In the marine biomass regeneration (MBR) project, we’re exploring a novel approach to add nutrients to the ocean to stimulate phytoplankton, which naturally sinks into the deep ocean and carries carbon away from the climate system.
Phytoplankton, which are microscopic algae, are the oceans’ primary producers. They do the vast majority of photosynthesis in the oceans, converting inorganic carbon to organic carbon in the ocean.
Some phytoplankton are consumed by zooplankton and enter the broader food chain. Others stick together to form marine snow – often observed by scuba divers and snorkellers in productive water, like around the UK – and this slowly floats down into the deep ocean; some of it makes it all the way to the sea floor.
The timescales for the water to come back to the surface are quite long. Once the material and the carbon it carries go down into the deep ocean, it can take hundreds to thousands of years before that carbon comes back to the surface. This makes this a long-term removal of carbon from the climate system.
We’re exploring a novel approach to add nutrients to the ocean to stimulate phytoplankton and to increase the natural uptake of carbon by these microalgae. The approach we’re looking at is using what we call “buoyant flicks”: using rice husks that are left over from farming and coating them with nutrients that the phytoplankton need. The advantage of this approach is that they can stay floating in the water and slowly release the nutrients to stimulate the algae.
The MBR project is being developed by a consortium including the University of Cambridge, University of Hawaii, University of Southern California, University of Capetown, and National Institute of Oceanography in India.
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You can read about one of our student's summer research project with Stanford University here.
Role of giant kelp in the surface waters of the deep ocean:
As a fast-growing marine organism, kelp has significant potential for carbon sequestration and could potentially play a crucial role in mitigating climate change.
Depending on the species, kelp can live for over a year and, during its life, can grow from two to 30 metres tall, with some species reaching growth rates of up to 61 centimetres per day. This rapid growth increases its capacity for photosynthesis, which, in turn, increases the absorption of carbon dioxide from the surrounding environment.
When kelp reaches the end of its life cycle, much of the carbon it has absorbed is stored in its tissues. As the kelp decomposes and sinks to the ocean floor, this carbon is effectively sequestered, delaying its release back into the atmosphere. Due to its high growth rate compared to land forests, kelp offers a unique advantage in terms of carbon sequestration, capturing CO2 at a faster rate than many land-based ecosystems.
At CCR, we are trying to further increase our understanding of how we might get more macroalgae to grow and provide new ecosystems in the ocean, together with a flux of carbon from the surface waters to the deep ocean. This project is being undertaken in collaboration with groups such as Kelp Blue.
Accelerated oxidation of methane:
Methane is a short-lived pollutant which drives climate change and harms human and ecosystem health by contributing to the formation of ground-level ozone. Methane is significantly more potent as a greenhouse gas than carbon dioxide (CO2): it is 120 times more potent upon emission and remains 80 times more potent over a time span of 20 years. The atmospheric burden of methane has almost tripled since the pre-industrial era due to both anthropogenic and natural emissions, contributing to 30% of global warming over the last 150 years.
Anthropogenic methane emissions can be partially reduced by improved engineering standards in the fossil fuel sector, but certain sources, particularly livestock and rice cultivation, are more challenging to address. Natural methane emissions are expected to continue growing, due to environmental feedbacks in wetlands and the cryosphere. Despite its potency as a greenhouse gas, methane can be abated through oxidation, specifically photocatalytic oxidation. By passing air over a substrate surface with a particular catalyst embedded, methane can be removed from the air, producing CO2 and water vapour.
We are working on the development of catalysts which could be applied to help not only reduce emissions from point sources of methane (such as cowsheds or old coal mines), but atmospheric conditions too. Dr Tzia Ming Onn is leading the research.
Strategies for the Evaluation and Assessment of Ocean based Carbon Dioxide Removal (SEAO2-CDR):
SEAO2-CDR aims to establish and evaluate the mechanisms and processes required to ensure the environmentally safe, socially acceptable and economically viable implementation of appropriate ocean-based CDR approaches in support of global climate policies. It will achieve this by developing the tools and frameworks that facilitate the evaluation and application of archetypal biological, chemical and physical ocean-based CDR techniques. Common assessment processes, governance structures and technologies will be used to explore system-level interactions between different approaches in order to deliver the insights, tools and guidelines required for the safe and effective implementation of ocean-based CDR. These advances will enable SEAO2-CDR to help establish the extent to which such approaches can support climate change mitigation and adaptation strategies and the transition to a climate-neutral and resilience society.
For more information, please visit the project website.
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