Harnessing the Power of the Ocean to Fight the Climate Crisis
photo: Cast B on Unsplash
The Earth Day is an opportunity to celebrate the awe-inspiring wonders of this planet – a place teeming with biodiversity hotspots, from lush rainforests to scenic mountain ranges, home to a wealth of endemic species. These pristine, ecologically unique landscapes are increasingly threatened by anthropogenic stressors such as greenhouse gas emissions, which exacerbate the harmful effects of climate change on people and the planet.
Tackling the climate crisis requires a multifaceted approach. We know we must quickly and dramatically reduce greenhouse gas emissions, including through a just transition to an economy powered by renewable energy. We must also be better prepared for the impacts of climate change that have already occurred or are expected to occur in the future.In recent years, climate litigation has increasingly been used to push governments and others to reduce emissions and invest in adaptation (see Sabin Center’s Climate Litigation Database here). International agreements such as the Paris Agreement, and US domestic legislation. and elsewhere, are also important in driving change.
While progress is being made, much work remains to be done. In addition to reducing emissions, greenhouse gases may need to be drawn from the atmosphere to slow climate change, the IPCC said.this Sabin Center for Climate Change LawAffiliates of Columbia Climate Schoolhave been exploring various approaches, including through “blue carbon” method. Blue carbon is Carbon captured by marine and coastal ecosystems. In this article, we will focus specifically on ocean-based carbon dioxide removal and storage, also known as “ocean CDR”.
The ocean covers 70% of the Earth’s surface and is a major carbon sink. Through natural processes, the oceans have so far absorbed about 25 percent of the carbon dioxide emitted by humans, and may absorb more in the future.Ocean uptake of CO2 occurs through two biological processes—for example, through carbon sinks such as phytoplankton and whale – and non-living.
Ocean-Based CO2 Removal Technologies
Schematic representation of several ocean-based carbon dioxide removal technologies. artwork: Rita Owen/GEOMAR
The Sabin Center for Climate Change Law has published a series of four white papers addressing the legal issues associated with a range of marine CO2 removal strategies, outlined below. These white papers by Romany Webb, Korey Silverman-Roati and Michael Gerrard provide the most comprehensive analysis of the legal aspects of marine CDR.These authors also published a book on “Ocean CO2 Removal for Climate Change Mitigation: A Legal Framework” this week. For the purposes of this article, we will provide a broad overview of these technologies, and the potential benefits and risks associated with them.
- artificial upwelling and downwelling: This technique involves the use of vertical pipes to circulate nutrient-rich water from the depths up to the surface, stimulating the growth of phytoplankton. Phytoplankton absorb carbon dioxide during photosynthesis, and pipes transport carbon-rich water from the surface to the depths.
- seaweed farming (Also known as seaweed farming): This method involves growing or cultivating seaweed, also known as macroalgae, which converts dissolved carbon dioxide into organic carbon as they grow through photosynthesis.The seaweed can then be harvested (e.g. for bioenergy or low-carbon products such as packaging made from seaweed) or sunk into the deep ocean for carbon sequestration. How long can biomass be quarantined? It depends on a variety of factors, including the location of the sinker.Biomass may be sequestered for 500 years If it sinks below 1,000 meters in some parts of the ocean, but if the biomass sinks in shallower waters, the length of time is much shorter.Environmental co-benefits include reduced levels of ocean acidification, etc..
- ocean fertilization (Also known as microalgae cultivation): In this technique, iron, nitrogen or phosphorus are discharged to the ocean surface to stimulate the growth of phytoplankton. The hope is that phytoplankton absorb carbon dioxide and then die and sink, carrying the carbon they contain to the deep ocean or in seafloor sediments for long-term storage. Some scientists speculate that these benefits could include increased growth rates of fish populations due to increased phytoplankton productivity, while others worry that this could lead to harmful algal blooms or possibly divert nutrients elsewhere.
- Increased ocean alkalinity (Also known as enhanced weathering): This method involves adding ground limestone or other alkaline rocks to seawater. The addition sets off a series of chemical reactions that allow the oceans to absorb additional carbon dioxide from the atmosphere. The materials needed for this approach would be mined on land and then spread on beaches or added to seawater via pipelines or ships. This approach has the potential to greatly speed up the process of natural mineral weathering, which absorbs carbon dioxide but typically takes thousands of years. Like seaweed farming, this would also lead to less ocean acidification. Potential risks include increased levels of toxic metals and other minerals, with impacts on biodiversity largely unknown.
law of the sea
Determining how and where these ocean CO2 removal technologies work best, what risks they pose and how best to ensure the marine environment is protected will all require ongoing research. Most technologies have not been tested on a large scale, and more investigation is needed before we can decide whether and how to use them to fight climate change.
While there are international and domestic laws governing ocean activities, such as the United Nations Convention on the Law of the Sea and the London Convention and Protocol, there is still a need to develop a strong legal framework specific to ocean CO2 removal research.
With this in mind, the Sabin Center developed and recently issued model legislation to advance CDR research for a safe and responsible ocean in the United States.According to a recent Opinion piece Authored by Korey Silverman-Roati and Romany Webb, the goal of this model legislation is to promote safe and responsible marine CDR research, including by “creating a licensing authority within a single federal agency, designating preferred areas for marine CDR research through simplified licensing, as And calls for a balance between climate goals and environmental risks.”
When conducting marine CDR research projects in the United States, high priority must be given to involving Native American tribes, states, and the public in these decision-making processes.If you are interested in learning more about the significance of this model legislation, please join this Internet Conference Presented by Ocean Visions, featuring Romany Webb, Associate Director of the Sabin Center.
The bigger question about these ocean-based CO2 removal technologies, especially those utilizing labor and cost-intensive technologies, is: Can these approaches make a meaningful contribution to the fight against climate change? Do the economic, social and environmental benefits and risks of these activities justify their use? Until we have clearer answers to these questions, we should not overlook collective action to substantially reduce existing emissions.
Can we avoid the worst effects of climate change? It depends on how fast we move. Our planet needs us to step up climate action now.
