Reaching promised climate targets will require the deployment of carbon dioxide removal (CDR). Marine CDR options receive more and more interest. Based on idealized theoretical studies, ocean alkalinity enhancement (OAE) appears as a promising marine CDR method. We provide an overview on the current situation of developing OAE as a marine CDR method and describe the history that has led to the creation of the OAE research best practice guide.

Ocean alkalinity enhancement is a promising approach for long-term anthropogenic carbon dioxide sequestration, required to avoid catastrophic climate change. In this chapter we describe its impacts on seawater carbonate chemistry speciation and highlight pitfalls that need to be avoided during sampling, storage, measurements, and calculations.

Ocean-alkalinity-enhancement technologies refer to various methods and approaches aimed at increasing the alkalinity of seawater. This chapter explores technologies for increasing ocean alkalinity, including electrochemical-based approaches, ocean liming, accelerated weathering of limestone, hydrated carbonate addition, and coastal enhanced weathering, and suggests best practices in research and development.

This chapter summarizes some key general considerations for experimental research methods  and compares the strengths and weaknesses of the different approaches. It also considers best practices relevant to ocean alkalinization enhancement, such as the need to properly monitor and consider the addition of trace elements and byproducts and potential interactions with other naturally occurring drivers.

Recent concern about the repercussions of rising atmospheric CO₂ as a key heat-trapping agent have prompted ocean experts to discuss ocean alkalinity enhancement (OAE) as a CO₂ removal approach but also as a potential way to mitigate ocean acidification. This chapter provides an overview of best practice in OAE laboratory experimentation by identifying key criteria to achieve high-quality results and providing recommendations to contrast results with other laboratories. 

Mesocosm experiments represent a highly valuable tool in determining the safe operating space of ocean alkalinity enhancement (OAE) applications. By combining realism and biological complexity with controllability and replication, they provide an ideal OAE test bed and a critical stepping stone towards field applications. Mesocosm approaches can also be helpful in testing the efficacy, efficiency and permanence of OAE applications.

Ocean alkalinity enhancement (OAE) is a marine carbon dioxide removal (CDR) approach. Publicly funded research projects have begun, and philanthropic funding and start-ups are collectively pushing the field forward. This rapid progress in research activities has created an urgent need to learn if and how OAE can work at scale. This chapter of the Guide to Best Practices in Ocean Alkalinity Enhancement Research focuses on field experiments.

In addition to emissions reductions, methods of actively removing carbon dioxide from the atmosphere must be considered. One of these methods, called ocean alkalinity enhancement, is currently being studied to evaluate its effectiveness and safety. This article details best practices for the study of natural systems to support the development of ocean alkalinity enhancement as a carbon dioxide removal strategy. Relevant Earth system processes are discussed, along with methods to study them.

This paper describes biogeochemical models and modelling techniques for applications related to ocean alkalinity enhancement (OAE) research. Many of the most pressing OAE-related research questions cannot be addressed by observation alone but will require a combination of skilful models and observations. We present illustrative examples with references to further information; describe limitations, caveats, and future research needs; and provide practical recommendations.

This article examines the legal considerations for research into ocean alkalinity enhancement (OAE). It analyzes relevant international law to identify minimum rules and standards that domestic laws may wish to incorporate. Domestic law should ideally align with international standards and assist researchers in designing OAE research projects. Collaboration between different disciplines helps develop a comprehensive legal framework for responsible OAE research, minimizing negative impacts.

To ensure that ocean alkalinity enhancement (OAE) research is attentive to societal priorities and does not prematurely engender widespread social rejection, it will be critical to understand the conditions most likely to lead to social approval. To facilitate this, we (1) characterize what is known to date about public perceptions of OAE, (2) provide suggestions on how to conduct public engagement, and (3) suggest how knowledge gained can be integrated into ongoing scientific work.

Monitoring, reporting, and verification (MRV) refers to the multistep process to quantify the amount of carbon dioxide removed by a carbon dioxide removal (CDR) activity. Here, we make recommendations for MRV for Ocean Alkalinity Enhancement (OAE) research, arguing that it has an obligation for comprehensiveness, reproducibility, and transparency, as it may become the foundation for assessing large-scale deployment. Both observations and numerical simulations will be needed for MRV.

This paper provides comprehensive guidelines for ocean alkalinity enhancement (OAE) researchers on archiving their metadata and data. It includes data standards for various OAE studies and a universal metadata template. Controlled vocabularies for terms like alkalinization methods are included. These guidelines also apply to ocean acidification data.