Since the industrial revolution carbon dioxide and other greenhouse gasses have accumulated in the atmosphere at dangerous levels. Drawing down greenhouse gasses is a way in which to reverse the impacts of climate change, not only causing emissions to stabilise, but potentially decrease.
Importantly, it offers a hope for the future.
Emissions reduction alone will not address the stock of greenhouse gases which already exist at dangerous levels in the atmosphere. Global emissions continue to rise. If we are to reach our Paris commitments of keeping global temperature rises well below 2°C, efforts need to be made to draw down carbon from the atmosphere. Ocean sequestration has significant potential as a means to draw down greenhouse gases at scale.
Policy instruments which can be used to sequester carbon include subsidies and carbon pricing mechanisms. It is also possible to use compliance mechanisms, such as making it a part of contract design 1. In order to achieve sequestration at scale, we will need to explore a combination of policy mechanisms.
1 I.M. Gren, & A. Z. Aklilu, ‘Policy Design for Forest Carbon Sequestration: A Review of the Literature’, in Forest Policy and Economics 70, 2016, pp. 128–136.
Ocean sequestration is a natural biological process integral to the global carbon cycle.
The ocean already functions as a natural carbon sink, with carbon sequestration occurring without any human intervention.
Ocean forestation, similar to land-based carbon capture through the growing of land based trees, aims to the scale natural process of drawing down CO2 through seaweed growth and then burying the carbon in the deep ocean.
Ocean sequestration can also include ocean fertilisation to stimulate the growth of plankton.
Carbon captured in seaweed farms can be sequestered through pelletisation into biochar, sinking seaweed fronds to the ocean floor, or alternative means.
Ways of achieving carbon sequestration include:
- Soil sequestration - Enhancing the storage of carbon in soil, such as through the use of ‘biochar’ to increase the soils capacity as a carbon sink, or through regenerative farming systems
- Plant sequestration - Enhancing the storage of carbon in forests and vegetation by slowing deforestation, or pursuing reforestation or afforestation
- Geo-sequestration– methods of storing CO2 in underground reservoirs / geology
- Mineral sequestration – storing carbon through chemical processes in stable carbonates
More experimental geo-engineering proposals include:
- adding sulphur dioxide to the atmosphere – to make it more reflective of solar radiation
- using shades in space – essential building complex space crafts to shade the earth from space
- ‘re-freezing’ the poles - by spraying salt into the atmosphere to make clouds more reflective
These geo-engineering methods do not draw down carbon dioxide. Rather than climate repair, they seek to mask the climate problem.
There are very few alternatives, yet rather than inventing something new, biological means such as the growing and sequestration of seaweed have the benefit of strengthening the Earth’s own self-regulation systems.
Almost all new technologies have unforeseen implications. It is only through research and attempting to achieve ocean sequestration projects that any effects can be understood. This is in part why the Ocean Forest Foundation has been established: to explore the feasibility of large scale ocean sequestration.
Through piloting smaller demonstration projects the process of ocean sequestration can be better understood and developed.