Zhenbang Hao

The soil-biosphere nexus is a critical component embedded in the concepts of soil security and ecosystem services (ES) and is directly linked to several global challenges identified by the United Nations (UN). Although soil security has been proposed as a policy framework, a major problem is that there are no standard procedures to assess the five dimensions of soil security: capability, condition, capital, connectivity, and codification in relation to the soil-biosphere nexus. This study proposes a land cover change matrix, disaggregated by soil type (“biophysical soil security matrix”), as a tool to evaluate the biophysical soil security continuum and its temporary changes, integrated with ES valuation. The matrix was tested using the state of Minnesota (MN) as a case study. Although the dominant soil orders in MN possess high natural capability, widespread human-caused land degradation has dramatically lowered their actual biophysical condition and has fueled massive soil decarbonization. Historic land degradation in MN due to human activity totaled 98,516 km² through 2024, with nearly 480 km² of anthropogenically degraded land created between 2001 and 2024. Based on carbon emissions alone, we estimate that historic land degradation in MN has resulted in total social costs of nearly $50B (U.S. dollars, B = billion = 10⁹) through 2024, with about 10% of this total social cost being realized between 2001 and 2024. Trends like this threaten soil security by directly eroding the soil’s capacity to sustain ES. Based on the analyses and results, this study recommends conducting both soil-centric and human-centric analyses of soil security to ensure the sustainable use of soil.

Teaching wetlands in a global context requires a pedagogical shift from local field observations to planetary systems analysis. This study proposes a teaching approach that integrates wetlands, analytical tools, policy frameworks, and a global purpose, which can be used in Earth science education. Laboratory exercise was developed and tested using wetlands (including a wetland of international importance and a Ramsar site: Congaree National Park) in the state of South Carolina (SC) in the United States of America (USA). Multidisciplinary students (wildlife biology, forestry, environmental and natural resources) engaged in active learning about subject matter definitions (e.g., hydric soils), used various geospatial analytical tools (e.g., Web Soil Survey), learned about Ramsar Convention (RC), and identified ecosystem services provided by wetlands for achieving the United Nations (UN) Sustainable Development Goals (SDGs). Results of two study years (2024 and 2025) were consistent, showing an increase in wetlands knowledge and applied analytical skills. The online quiz, taken by 113 students, had an average score of 9.3 out of 10. Students increased their knowledge of UN SDGs and ranked SDGs 6, 13, 14, and 15 as the most relevant SDGs to wetlands. A newly proposed teaching approach can be adopted worldwide, as most materials and tools are publicly available.

Wetlands are an important part of the Ramsar Convention (RC) and Kunming-Montreal Global Biodiversity Framework (KM-GBF), which is a significant agreement committing 196 countries (the United States is not a participant of KM-GBF) to a reduction and halting of the loss of biodiversity by 2030. In comparison to the broadly focused KM-GBF, goals of RC (172 contracting parties) are wetlands-focused such as “wise use” and protection of wetlands, selection of wetlands of “international importance”, and international collaboration. The goal of this study is to explore how improved wetlands analytics can help achieve the goals of both the RC and KM-GBF using the state of North Carolina (NC) in the United States of America (USA) as an example. Several goals and targets of KM-GBF are applicable to wetlands, with only a handful of indicators (e.g., wetland extent trends (WET) index) to monitor them. The WET index is only relevant at the global or continental scale because it relies on a limited database of wetland sites over time. Unfortunately, the WET index does not allow tracking of smaller spatial extents and new methods are needed to understand how wetlands are changing over time. Geospatial analysis results and recommendations are presented for both RC and KM-GBF. Loss of wetlands can result in transboundary damage, harming biodiversity and ecosystem functions and services (ES). A case study of NC showed that almost 49% of the wetland area was lost between 1780 and 1980 in the state. Wetlands loss in NC continued between 2001 and 2021. Future RC and KM-GBF refinements could use sea level rise analysis to evaluate changes in wetlands.

Mountain ecosystems, strongly affected by climate-related variability and human impact, are degrading faster than other terrestrial ecosystems. Currently, the United Nations (UN) utilizes Sustainable Development Goal (SDG) 15: Life on Land (Target 15.4 and Sub-indicators 15.4.2a and 15.4.2b), along with the System for Earth Observation Data Access, Processing and Analysis for Land Monitoring, commonly referred to as SEPAL, to track mountain degradation. This SEPAL analysis does not include soil data, which is critical to understanding mountain degradation. The present research focuses on improving the tracking and evaluation of mountain land degradation (LD) utilizing soil data in the state of Colorado (CO) in the United States of America (USA) as an example. Total anthropogenic LD affects an estimated 19% of Colorado’s territory as of 2024, driven mainly by agricultural activities (80%). Between 2001 and 2024, overall LD in CO decreased (−0.4%), but LD from development increased by 23.3%. For mountain areas in CO, the mountain green cover index (MGCI) was 96% for 2024, and it decreased (−0.4%) between 2001 and 2024. The mountain LD proportion was 2.5% as determined by the SEPAL method compared to 4.4% by LULC analysis. Incorporation of soil data into LULC analysis found that between 2001 and 2024 LD increased to 6.6%. All soil types in the mountains exhibited anthropogenic LD due to development with a total developed area of 1385.1 km². Current total mountain LD (inherent + anthropogenic) in CO may be as high as 38.9%. Future estimates of total mountain LD should include both inherent and anthropogenic LD.

The Kunming-Montreal Global Biodiversity Framework (GBF) is an important agreement committing 196 countries (the United States is not part of GBF) to reduce and stop the loss of biodiversity by 2030. Biodiversity and soil diversity (pedodiversity) are intricately linked by sharing biosphere. Similarly to biodiversity, pedodiversity is classified using various classification systems adopted by countries in the world (e.g., United States Soil Taxonomy). The loss of pedodiversity is often caused by land use and land cover (LULC) changes, which impact biodiversity. These losses need to be acknowledged and accounted for by the GBF. The innovation of this study is that it proposes to include pedodiversity and its metrics into the GBF using the contiguous United States of America (USA) and GBF targets as an example. This study proposes to use geospatial technologies (e.g., land cover change matrix) linked to soil databases to monitor temporal changes and no net loss in pedodiversity. Loss of pedodiversity can result in damages (e.g., pollution), which can harm biodiversity and ecosystem functions and services (ES). As of 2021, over two million square kilometers were anthropogenically degraded in the contiguous USA, with all ten soil orders being affected by this degradation (relevant to target ten focused on the sustainable use of natural resources). Analysis of changes in LULC between 2001 and 2021 showed an increase in anthropogenic land degradation (LD) (+3.4%), which resulted in a net loss of pedodiversity and affected all of the ten soil orders in the contiguous USA. Future GBF refinements could use pedodiversity metrics to analyze the ability to support biodiversity.

The concept of nature-based solutions (NBS) is widely promoted as an approach to effectively counteract climate change and land degradation (LD) as well as simultaneously add environmental and socio-economic benefits. To have a worldwide impact from NBS, it is important to consider potential land and soil resources at various scales, including administrative units (e.g., country, state, county, etc.). Nature-based solutions are considered by many United Nations (UN) initiatives, including the Paris Agreement and the UN Convention to Combat Desertification (UNCCD). Currently, there is no consensus on how to define NBS and their indicators. The innovation of this study is that it defines and evaluates soil- and land-based NBS potential while suggesting indicators for land- and soil-based NBS using the contiguous United States of America (USA) as an example. This study defines potential land for NBS as the sum of the individual satellite-identified areas of barren, shrub/scrub, and herbaceous land covers, which are linked to climate and inherent soil quality (SQ), so that NBS could be implemented without changing other land uses. The potential soil for NBS, based on SQ, is a subset of land available for potential NBS. As of 2021, anthropogenic LD affected 2,092,539.0 km² in the contiguous USA, with 928,618.0 km² (15.1% of the contiguous US area) of actual potential land for NBS. The contiguous USA had a negative balance between anthropogenic LD and actual potential land for NBS to compensate for anthropogenic LD of −1,163,921.0 km². Thirty-seven states also exhibited a negative balance for LD compensation with Iowa having the worst balance of −124,497.0 km². Many states with positive anthropogenic LD and NBS balances showed that most of the potential NBS land was of low SQ and, therefore, may not be suitable for NBS. Planning for NBS should involve a feasibility analysis of “nationally determined NBS” (NDNBS) through site and context-specific NBS.