Assessment of the NASA carbon monitoring system wet carbon stakeholder community: data needs, gaps, and opportunities

Wet carbon (WC) ecosystems are a critical part of the carbon cycle, yet they are underrepresented in many policy and science communities due to the relative under-investment in stakeholder and boundary organizations. WC systems include the hydrosphere and carbon cycling systems that operate in wetlands, oceans, rivers, streams, lakes, ponds, and permafrost. In this article, we provide evidence from a desk review of WC stakeholders, that includes individuals, groups or organizations that are affected by climate change, and utilize carbon data. These stakeholders are involved in decision-making processes in WC ecosystems, and can be private companies, non-governmental organizations, government agencies ranging in scope from local to federal, parastatals, international organizations, and more. In this paper, we identify and describe the links and interests of WC stakeholders and analyze the gaps between scientific understanding and information needs. A continued focus on WC systems could lead to increased stakeholder engagement and methodological and scientific progress. Our study revealed that stakeholder interest in WC systems was not primarily determined by its role in the carbon cycle, but rather by its significance for local policy, economics, or ecology. To bridge the gap between stakeholders and available WC data, we need improved communication of data availability and uncertainty, capacity building, engagement between stakeholder groups, and data continuity. Enhanced stakeholder engagement across various systems will facilitate greater utilization of carbon monitoring data derived from remote sensing; thereby creating more informed stakeholders as well as more effective decision-making processes.


Introduction
Understanding the long-term impacts of changing climate requires knowledge of the global carbon cycle (Michalak et al 2011). The global carbon cycle encompasses a suite of physical and biogeochemical processes by which carbon is dynamically exchanged between the biosphere, hydrosphere, geosphere, and atmosphere (Ver et al 1999). Although previous research has focused on the impacts of a changing environment on the biosphere (Keith et al 2021) and atmosphere (Xiao et al 2019), here we concentrate on the hydrosphere and carbon cycling systems that operate in wetlands, oceans, rivers, streams, lakes and ponds as well as in permafrost. Collectively known as wet carbon (WC) systems, they are critical to the carbon cycle (Campbell et al 2022). They are also essential to support humanity, including agriculture, hydroelectric power, groundwater systems, and a multitude of sanitary and drinking water systems. Fish and seafood are a primary source of protein for more than 1 billion of the poorest people on earth (FAO 2010) and fishery and aquaculture sectors are the source of income for millions of women and men in low-income families (Béné et al 2015).
A recent review of monitoring WC via remote sensing (Campbell et al 2022) examined 574 publications across nine WC systems: mangroves, tidal marshes and flats, mineral wetlands, peatlands, permafrost, lakes, rivers, oceans, and coastal and continental shelf seas. By including all freshwater, saline and brackish aquatic and wetland ecosystems, the review focused on a broad grouping of carbon-cycle systems with shared data needs, restoration and preservation priorities, and research directions. Remote sensing data and in situ measurements provide the necessary inputs to fine-tune models for monitoring WC systems, enabling improved understanding of how global environmental change may affect these critical systems.
Understanding and tracking the impact of net carbon emissions on the carbon cycle is the focus of monitoring, reporting and verification (MRV), an area of research that has rapidly expanded over the past few decades (Krug 2018). The National Aeronautics and Space Administration (NASA) carbon monitoring system (CMS) program aims to inform regulatory and management policy decisions from the local to international levels by using NASA's science centers and NASA-funded investigators to create and improve the accuracy of carbon data products for stakeholder use . Furthermore, they aim to create carbon MRV systems and improve their accuracy to increase their functionality for carbon trading programs (Hurtt et al 2019). The NASA CMS program focuses on prototyping methods of MRV for the entire carbon cycle, including WC systems.
Stakeholder engagement plays a major role in the CMS program. We define stakeholders as individuals, groups or organizations that are affected by climate change, and who use CMS data to make policy, investment, or activity decisions with carbon data as well as provide outreach and education. They are involved in WC decision-making processes in the systems of interest, and can be private companies, nongovernmental organizations (NGOs), government agencies ranging in scope from local to federal, parastatals, international organizations, and more . CMS stakeholders can also include cities and townships, international organizations, nongovernmental bodies, universities, and sub-national bodies (Campbell et al 2022). The objective of this paper is to identify and characterize stakeholders associated with WC systems, evaluate their interests and relationships with the system, and determine existing gaps between scientific knowledge and their information requirements.
In this study, we conducted a desk review of individuals and organizations who are part of the scientific community and who use WC data from funded CMS activities. Our primary objective was to gain valuable insights into the ways in which stakeholders involved in WC utilize information in their work, and to identify any existing unmet information requirements. Specifically, the focus of research was to assess whether the current datasets and the research presented in the academic review of Campbell et al (2022) are adequate to support the current decision-making processes and to gauge the knowledge and awareness of organizations about satellite-derived carbon datasets.
We conducted a desk review to identify organizations that work and focus in the following ten categories listed in Campbell et al (2022): Identifying areas where there is a clear need and demand for data, but where few datasets are available, or where there is poor knowledge of existing datasets, presents a unique opportunity for the scientific community. By recognizing and addressing these gaps, the scientific community can develop new datasets and research to support these areas, which can further scientific understanding and inform decision-making processes.
To conduct our review, we used a search engine to identify non-profit, government, companies or research institutions that used the keywords 'blue carbon' or 'WC' on their website as part of the organization's focus or in the description of a specific project. Next, we looked for organizations by combining 'carbon' with a category from Campbell et al (2022) (e.g. 'carbon mangroves' or 'carbon seagrass'). To be included as an organization in the desk review, their website's information about their work with WC had to be within the last 3 years and have direct indication of WC work or use of research. Indicators of WC work include a description of their work with carbon, a staff member's bio that describes a focus in WC, or a blog post/website feature detailing work in WC.
We identified 183 organizations and institutions in the WC area, with NGOs being the most common and comprising 30.6% of the total. Figure 1 shows the different types of institutions we identified in the desk review.
We also extracted from CMS project summaries during the 13 years of the program's existence the total number of projects that mention keywords from Campbell et al (2022). We found that there have been 106 funded projects during the CMS program that include one of the ten keywords mentioned. Here we report on the percentage of each WC category of these 106 projects.

Results
We found that seagrass, permafrost, and peatlands appear to be among the least interesting research categories for stakeholders as there are the fewest stakeholder organizations working on them. Peatlands have the largest percentage of research papers on WC, followed by ocean research. Mangroves do not appear to be a leading category either in terms of research, CMS projects or stakeholders. We found that carbon in tidal marshes and wetlands are an important focus of our stakeholders, while there is a noticeable lack of ocean or ocean shelf stakeholders despite their critical role in the carbon cycle. This section highlights the outcomes of the desk review, especially pertaining to the activities of stakeholders, their use of carbon datasets, and their interest in scientific information.
Our desk review indicated that from a disciplinary perspective, the WC community is highly diverse, and includes those working in open oceans, coastal marine waters, and lacustrine ecosystems, as well as in wetlands, forested wetlands, and mangroves. Figure 2 shows the areas that the 183 organizations work in, with 28% of stakeholders working in the ocean, but nearly twice working on the coastline or ocean shelf area where most of the economic value is generated through fishing, recreation, and farming. These coastal environments are both rising in acknowledged importance and have targeted ecosystem and carbon management strategies in the stakeholder community, including reforestation and protection.
Although mangroves comprise only a small fraction of the global forested area (0.3%-0.5%) they have significant carbon storage capacity. There have been new data products created that use satellite remote sensing, which has enabled the mapping of previous and current mangrove forests (Bunting et al 2018, Lagomasino et al 2019. They are also increasingly recognized as central to coastal protection from the impact of storms and sea level rise (Spalding et al 2014). There has been significant effort in using satellite remote sensing data, tested at sub-national regions, to create global, consistent time series such as has been done by Global Mangrove Watch, a scientific data initiative that has mapped mangrove change and provided carbon monitoring data (Bunting et al 2018). Although 12% of the research focuses on mangroves, our desk review revealed that only a small fraction of institutions (5% of the total) are using and only 6% of all CMS projects are developing these datasets.
Studying submerged aquatic vegetation (SAV), including seagrass and kelp, is an active area of interest to researchers, and our study shows a 41% increase in research in this area since 2004 (figure 3). Along with permafrost and peatlands, SAV is an important potential target for carbon sequestration and economic development across multiple regions. Aquatic vegetation and macroalgae are estimated to store 10%-20% of the ocean's carbon within 0.2% of the total ocean area (Mcleod et al 2011). However, since seagrass and kelp biomass are below the water surface, mapping their extent and carbon concentration both by conventional and non-conventional means is problematic. As a result, their spatial extent has been shown to be an order of magnitude less than the modeled extent (Jayathilake and Costello 2018, Duffy et al 2019), but significant effort is being directed into identifying SAV areas and quantifying their biomass (Campbell et al 2022, Lebrasse et al 2022. Only 1% of all CMS projects focus on creating carbon datasets with remote sensing information. We anticipate a significant rise in stakeholder interest in these biomes in the upcoming years.
The desk review found that permafrost and peatlands ranked among the areas of least interest to our stakeholder institutions, with 1.6% and 3.8% identified as showing interest or activity in these regions. Although peatlands take up approximately 3% of the earth's terrestrial area, these ecosystems represent approximately 30% of the total belowground soil organic carbon (Xu et al 2018). Permafrost, which dominates peatland types, is both remote and isolated from human population centers and economic activities. However, it is widely recognized that including boreal and permafrost peatlands is critical for understanding the global carbon cycle. Peatlands pose unique challenges to in situ and remote sensing data collection and data production (Campbell et al 2022). Although these ecosystems are rarely the target of stakeholders, new initiatives such as the International Union for Conservation of Nature (IUCN) United Kingdom and NASA's Arctic-Boreal Vulnerability Experiment (ABOVE) seek to promote peatland restoration, improved policy, increased focus on identifying new science data users and fund usable science related to these ecosystems (IUCN 2018, Brown et al 2020. Similarly, our results showed that carbon derived from lakes, ponds (10.4%), rivers, and streams (3.8%) is also infrequently the focus of stakeholder engagement, with few organizations creating or using carbon data on these ecosystems. Nearly 24% of all CMS projects in the WC space provide some information about rivers in their analysis. Freshwater lakes and ponds are very diverse and numerous and support food production systems, tourism, drinking water and other critical economic livelihoods (Ssekyanzi et al 2021). Campbell et al (2022)'s review pointed that recent research indicates significant variability in cycling of carbon in individual lakes, depending on a range of factors. Given their size and the difficulty in observing their carbon cycling, much more work is needed to gain a comprehensive understanding of these processes and to develop management policies relevant to carbon management.
Our categorization of ocean stakeholders into two distinct groups, namely, ocean and ocean shelf, has revealed that the number of organizations associated with the ocean is only half as many as those related to the ocean coastline category. This lack of ocean stakeholders stands in contrast to the oceans being the largest reservoir of carbon on the planet with recent estimates suggesting that oceans sequester the equivalent of more than 40% of anthropogenic CO 2 (Friedlingstein et al 2020). The disparity between the substantial role that oceans play in the carbon cycle and the limited number of stakeholders involved in ocean carbon cycle applications underscores the urgent need to engage with additional potential stakeholders beyond those examined in this study. Further research is needed to reach out to these stakeholders and expand the scope of ocean carbon cycle applications.

Discussion
This analysis has showed the critical need for additional WC related datasets to meet the policy and decision making in environmental management.
Here we provide additional information on the reasons behind the lack of WC stakeholders, the need for information on carbon across different sectors critical for carbon cycling.

Ocean carbon stakeholder context
Despite the size and importance of ocean-related carbon, and its critical role in balancing carbon between the ocean and atmosphere for an equitable climate future, only a limited number of stakeholders expressed relevance or interest in any of these three categories, (open ocean, ocean shelf and coastal ecosystems) and their use in carbon accounting. Some of the major challenges in identifying stakeholders for ocean carbon systems stem from: (1) Lack of awareness of the importance of the oceans in carbon sequestration, (2) Poor representation of ecosystem services and the scale of economic significance provided by the oceans' biological pump in carbon policy and management narratives, (3) problems in determining jurisdictional boundaries in the oceans and (4) perception that land based carbon systems are static and easier to map while oceans are dynamic and so difficult to map.
While stocks and flows of carbon in the ocean have been identified and described in broad terms, the role of the oceans as a long-term sink for anthropogenic carbon is not well known to stakeholders (Luisetti et al 2013). None of the IPCC projections address accuracy of current estimates of global ocean primary production or export of carbon, and there is no effort to understand the socio-economic costs (Luisetti et al 2013) associated with the projected reduction in the global ocean's carbon sequestration service anticipated in warming and increasingly stratified oceans (Rogers et  Every coastal country (sovereign state) has an EEZ which stretches generally 200 nautical miles (370 km) offshore (as defined by the United Nations Convention of the Law of the Sea, 1982). Within the EEZ, each country has the rights and jurisdiction to manage its marine resources, and the management strategies employed by each country differ. Waters not within an EEZ are termed the high seas, or more informally 'international waters' , and are under international jurisdiction. However, there are agreements in place for certain activities within international waters, and international bodies for marine and ocean management (e.g. the Intergovernmental Oceanographic Commission (IOC) of UNESCO). Building relationships and engaging with these stakeholders with such a diverse portfolio (e.g. IOC) is challenging and time-consuming, particularly when these stakeholders do not have existing mechanisms for monitoring carbon emissions.

Ocean carbon monitoring challenges
The ocean contains the largest reservoir of carbon on the planet, 37 000 Gt of dissolved inorganic carbon (DIC), and the ocean's organic carbon pool (700 GtC) is equivalent in size to the atmospheric carbon dioxide pool (Friedlingstein et al 2020). The flux of carbon into the oceans from the atmosphere, the movement of carbon from the surface ocean into its interior, and the exchange of carbon between the different carbon pools are controlled by ocean chemistry, biological processes, and physical conditions. There is a suite of observing platforms used for oceanic carbon monitoring on different temporal and spatial scales (e.g. satellites, moorings, buoys, autonomous underwater vehicles), each with different advantages and limitations. Our review showed a significant interest in networks that shared these data across multiple organizations, with 16 organizations identified in the desk review. For example, satellites only observe the surface ocean and do not capture deep ocean processes, whereas buoys or moorings can monitor below the surface but are fixed at one location. Therefore integrating these data sources is key to developing a comprehensive monitoring system.
Remote sensing of ocean biology and biogeochemistry relies on measurements of ocean color. Phytoplankton primary productivity and particulate carbon pools directly influence ocean color, thus research has focused on developing methods for monitoring this aspect of the carbon system (Behrenfeld et al 2005, Westberry et al 2008, Silsbe et al 2016, Mitchell et al 2017, Stramski et al 2022, Wu et al 2022. A major challenge in oceanic carbon monitoring has been the development of methods targeting the dissolved carbon pools ((DOC) and DIC) because they have limited or no impact on ocean color. Chromophoric dissolved organic matter (CDOM) is a subset of the DOC pool, and as it is colored it can be used as a proxy for DOC estimation (Mannino et al 2014, Cao et al 2018, Juhls et al 2022. Robust relations between DOC concentration and CDOM absorption (both as a function of depth or when isolated by an ocean basin) have eluded researchers (Nelson et al 2010, Nelson andSiegel 2013). More recently, researchers have found success in estimating DOC and DIC from space using machine learning techniques and combining ocean color, sea surface temperature and salinity satellite observations with reanalysis data products (Aurin et al 2018, Gregor and Gruber 2021, Bonelli et al 2022.

Future directions in ocean carbon stakeholder engagement
Moving forward, one promising approach to generate stakeholder interest in ocean carbon sequestration, is to assign a monetary value to the carbon cycle of the ocean. This can be achieved through carbon accounting, whereby the benefits of climate change abatement afforded by the oceans are quantified for every ton of carbon prevented from accumulating in the atmosphere. Assigning such a cost would not only allow a better cost comparison with land-based ecosystem services, but also help in charting alternative mitigation pathways and adaptation interventions across future socio-economic scenarios. Better predictions of the long-term consequences of climate change would aid governments and institutions craft better policies and frameworks for adaption and reduction of damages as well as society's willingness to pay for CO 2 abatement required to constrain planetary temperature increases. The value in loss in carbon sequestration service in the North Atlantic was estimated to be in the range of $170-3000 billion in mitigation costs and $23-401 billion in social adaptation costs (Barange et al 2017).
Marine food webs regulate carbon through a complex network of processes. They are a major component of the Earth's carbon system and thus it is imperative that global ecosystem models capture carbon flows through marine food webs (Stock et al 2014). Furthermore, changes in oceanic chemistry could impact the growth of marine organisms, particularly those that make calcium carbonate shells such as oysters, lobsters, and molluscs (Doney et al 2020). It is through these economically important species that the potential of a CMS focused on ocean acidification and changes in ocean carbonate chemistry could provide an avenue for engaging stakeholders. Other potential ocean carbon stakeholders include water quality managers (as DOC can act as a tracer for nutrient fluxes into aquatic systems) or those interested in water clarity (tourism and sports fishers) and underwater vision (e.g. defense industry).
Given the global ocean's potential for longer-term CO 2 sequestration through marine carbon dioxide removal (NASEM 2022), it is becoming increasingly important to establish a CMS, but the question still remains: which stakeholders hold the jurisdiction for implementing such a system?

Blue and teal carbon stakeholder context
Blue carbon includes coastal ecosystems such as wetlands, mangroves, salt marshes, and sea grasses, and is an attractive climate mitigation target due to the large volumes of carbon stored. Blue carbon is a major driver of WC science and policy needs and is associated with numerous societal and ecological benefits for local communities.
For example, NASA's BlueFlux project is designed to develop mangrove carbon budgets for both carbon dioxide as well as methane, where methane emissions to some degree offset climate mitigation (Poulter et al 2023). Stakeholders identified within the BlueFlux project with interests in mangrove carbon budgets anticipate that these carbon datasets will help them address the numerous opportunities emerging for conservation, restoration, and the need for greenhouse gas accounting to inform new market opportunities and incentives.
Unlike the oceans, terrestrial wetlands have clearer jurisdiction and a large community of potential stakeholders with decision-making and policy making capabilities. While the existing network of wetland laws and policy tools are complex, they provide a framework to directly implement actionable science into decision-making and monitoring activities. However, despite the available avenues for actionable science and a large potential community of stakeholders within the terrestrial wetland community, we found that few stakeholders are using CMS related products in their work.
For example, the wetland community has data from wetland mapping over the past three decades, but this data has not been utilized to garner information on changes to wetland boundaries, ecosystem health, and/or degradation due to invasive species etc. Although individual wetlands are well studied and characterized, changes in wetland health over the entire land cover class through time is largely unavailable to the community. A lack of fundamental remote sensing baselines, such as location, extent, and change for terrestrial wetlands is critically needed foundation for WC monitoring (Campbell et al 2022).
Although terrestrial wetlands in the United States account for nearly ten times more carbon (termed 'teal carbon' by Nahlik and Fennessy 2016), than tidal saltwater sites, the teal carbon wetland stakeholder community is generally far less developed compared to the blue carbon community. This lack of a strong and organized terrestrial WC stakeholder community may be due to the lack of awareness within the community of the role of wetlands in the carbon cycle, limited research on carbon dynamics within wetlands, and few economic incentives compared to other ecosystems (e.g. forests). While the number of remote sensing publications referencing blue carbon has grown exponentially over the last decade, research focused on remote sensing of teal carbon is far less (Campbell et al 2022) and is largely focused on peatlands. Only 7% of CMS products are related to terrestrial wetlands. While wetlands in the United States are regulated through a series of federal, state, and local laws, with provisions under the Clean Water Act as the primary federal policy tool, they rarely contain clear incentives related to carbon management.
As scientific research on teal carbon grows and new insights arise, it has the potential to shape policy and incentive programs, leading to the demand for increased and improved decision-making capabilities. For example, recent research demonstrated that forested inland wetlands in the Pacific Northwest stored three times more carbon than the old growth trees in the same watershed. These discoveries as well as easily understood maps derived from remote sensing data products may energize greater interest in carbon within the wetland community.

Land management needs for WC data
WC stocks and fluxes are affected by numerous ongoing land management activities, such as agricultural conservation to mitigate water pollution; however it is not explicitly considered as an indicator of the sustainability of the system of concern. For example, the heath of streams and estuaries in the Chesapeake Bay watershed has been declining for several decades mainly caused by excessive amounts of nitrogen, phosphorus, and sediment from terrestrial ecosystems (CBF 2016), with agriculture contributing 40% of the nitrogen, 58% of the phosphorous, and 60% of the sediment entering the Bay. Therefore, agricultural conservation practices (such as cover crops, stream buffer and nutrient management) are being promoted solutions to address water quality degradation and sequester carbon into soils (CBF 2022). As nutrient and carbon cycles are closely coupled, water quality mitigation practices are poised to influence the amount of carbon transported from land to river networks, estuaries, and oceans.
For stakeholders who are managing WC, better understanding and monitoring of the sources of carbon entering wet environments is needed. For example, the New York City water supply system, which includes a diverse network of 19 reservoirs and three controlled lakes in the upper state of New York, faces the challenge of increased natural organic matter concentrations in source waters after storms and floods and associated risks of toxic disinfection byproducts van Dreason 2014, Du et al 2019). Sources of carbon in reservoirs can be traced to different land use/land cover (e.g. forests, grassland, cropland, and wetland (Wilson and Xenopoulos 2009, Abril et al 2014, Yang et al 2017, Williamson et al 2023) and atmospheric deposition (Liptzin et al 2022). Although New York City is a pioneer in safeguarding source waters via effective watershed management (NASEM 2018), there remains a significant uncertainty of the magnitude and spatial-temporal distribution of those sources, which creates a challenge in successful WC management. Accurately quantifying the causal relationships between the WC system and other interactive terrestrial and atmospheric systems is crucial for effective management of WC to achieve ecological, climatic, and socio-economic goals.

Gaps and conclusions
This paper has identified gaps or mismatches between data availability and the data need in the WC regime. These are: • There is a scarcity of wetland data as there are no stakeholders actively seeking it. However, without a baseline, it becomes difficult to discuss any changes or trends. Therefore, initial maps are crucial. • There are few incentives for wetland stakeholders to focus on carbon because wetland extent is very driven by regulations. Despite this, carbon in terrestrial wetlands is substantial and should generate significant interest in the carbon market community (Mack et al 2021). • The issue of jurisdiction in deep oceans remains ambiguous, as there are only a handful of identifiable stakeholders and non-profit organizations with sufficient motivation to address it. Boundary organizations working in WC are only slowly starting to think about carbon. • There are decades of delay between when and how carbon changes in the deep oceans and when we can measure dissolved organic or inorganic carbon due to circulation patterns that transport these constituents. Further research is needed to spur increased attention and facilitate the creation of datasets given the critical importance of oceanic ecosystems on carbon sequestration and cycling. • Small organizations and county and state governments focus on managing nutrients, agricultural productivity, and other land activities, without explicitly labeling these activities as part of carbon cycle science. They generally allocate their resources to nutrient production and harmful algal blooms which are highly relevant to carbon cycling, as was demonstrated by the Chesapeake Bay program. • Boundary organizations can bridge communication gaps between regulatory agencies focused on carbon cycle issues and scientific communities. These boundary organizations would be responsible for communicating relevant scientific data to decision-makers in regulatory agencies, particularly those who focus on issues related to the carbon cycle. By doing so, they would help ensure that the activities of regulatory agencies are informed by the latest scientific research on carbon cycle science datasets.
The institutions identified during the desk review presented here were sampled from partners involved with NASA CMS supported projects. While the institutions identified represent the diverse interests across WC systems, we note that there are additional institutional opportunities that CMS could consider in the future. These include partnerships with Minority Serving Institutions, Historically Black Colleges and Universities, and with Tribal nations. Through NASA's funding portfolio there has been an increase in opportunities to partner with historically underrepresented organizations thus providing the financial resources to develop and sustain such partnerships. We recommend that continued emphasis, support, and training be provided to expand the diversity of stakeholder institutions involved with WC initiatives.
As carbon cycle science continues to gain momentum, an increased focus on trends, time series and understanding change is key. We suggest putting more effort on data continuity, where we identify 'essential climate variables' relevant to the WC user community and transfer the code and models to local and/or international agencies. This will ensure that data is available and supported in the long-term as well as provide opportunity for the WC community to grow. For oceans, particulate organic and inorganic carbon products, including pools and fluxes are essential. Algorithms that produce remotely sensed carbon products covering the open ocean and ocean shelves are needed to ensure engagement across long periods. Finally, the WC community needs to identify and engage stakeholders in the research process from the initial stages via the co-production of knowledge and emphasize two-way communication and promotion of the use of data as they are developed.

Data availability statement
All data that support the findings of this study are included within the article (and any supplementary files).