Abstract
Blue carbon is the carbon storage in vegetated coastal ecosystems such as mangroves, salt marshes, and seagrass. It is gaining global attention as its role in climate change mitigation and ...local welfare growth. However, a global assessment on the long-term spatiotemporal sustainable development status of blue carbon has not been conducted, and the relations among blue carbon ecosystems, driving forces for climate change mitigation, and socioeconomic interventions for development capacity on a global scale are still unclear. Here, we constructed a blue carbon development index (BCDI), comprising three subsystems: driving force, resource endowment, and development capacity, to assess the sustainable development level of 136 coastal countries’ blue carbon over 24 consecutive years and explore the relationship among subsystems. We further propose a cooperation model to explore the feasibility of global blue carbon cooperation and quantify benefit allocation to specific countries. The results showed an upward trend in BCDI scores with variations in regional performance over the past two decades, and we found a positive correlation between development capacity and blue carbon resource endowment. Based on the scenario simulations of global cooperation, we found that coastal countries could improve the global average BCDI score, add 2.96 Mt of annual carbon sequestration, and generate $136.34 million in 2030 under Global Deep Cooperation scenario compared with the Business-As-Usual scenario.
The exotic plant Spartina alterniflora was introduced to Yueqing Bay more than 20 years ago for tidal land reclamation and as a defense against typhoons, but it has rapidly expanded and caused ...enormous ecological consequences. Mapping the spread and distribution of S. alterniflora is the first step toward understanding the factors that determine the population expansion patterns. Remote sensing is a promising tool to monitor the expansion of S. alterniflora. Twelve Landsat TM images and Support Vector Machine (SVM) were used to delineate the invasion of S. alterniflora from 1993 to 2009, and SPOT 6 images and Object-Based Image Analysis (OBIA) were used to map the distribution of S. alterniflora in 2014. In situ data and Unmanned Aerial Vehicle (UAV) images were used as supplementary data. S. alterniflora spread rapidly in Yueqing Bay over the past 21 years. Between 1993 and 2009, the area of S. alterniflora increased by 608 times (from 4 to 2432 ha). The rapid expansion of S. alterniflora covered almost all of the bare mudflats around the mangrove forests and the cultivated mudflats. However, from 2009 to 2014, the rate of expansion of S. alterniflora began to slow down in Yueqing Bay, and the total area of S. alterniflora in Yantian decreased by 275 ha. These phenomena can be explained by the landscape changes and ecological niches. Through the expansion of S. alterniflora, it was found that the ecological significance and environmental impact of S. alterniflora was different in different regions in Yueqing Bay. The conservation plans for Yueqing Bay should consider both the positive and negative effects of S. alterniflora, and the governmental policy should be based on the different circumstances of the regions.
Based on satellite-observed and reanalysis data, this study investigates a thermal front east of the Gulf of Thailand (TFEGT) during the winter from 1982 to 2021. TFEGT exhibits distinct seasonal and ...interannual variation, emerging in December, peaking in February, gradually diminishing in March, and completely dissipating in April. Notably, the occurrence probability, area, and intensity of the thermal front are significantly higher in January and February compared with December and March. Through the application of a mixed temperature equation, we identify that geostrophic advection, driven by wind-induced western boundary current in the South China Sea (SCS), plays a crucial role in the formation of the TFEGT. In winter, the prevailing northeast monsoon propels the western boundary current through wind stress curl, causing the southward transport of cold water from north to south. This cold water encountered warm water within the Gulf of Thailand (GoT), leading to the formation of TFEGT. Furthermore, the interannual variation of TFEGT is closely associated with the El Niño-Southern Oscillation (ENSO). In El Niño (La Niña) years, the northeast monsoon weakens (enhances), resulting in a weaker (stronger) western boundary current, ultimately influencing the weakening (enhancement) of TFEGT.
The frequent occurrence of extreme weather and the development of urbanization have led to the continuously worsening climate-related disaster losses. Socioeconomic exposure is crucial in disaster ...risk assessment. Social assets at risk mainly include the buildings, the machinery and the equipment, and the infrastructure. In this study, the wealth capital stock (WKS) was selected as an indicator for measuring social wealth. However, the existing WKS estimates have not been gridded accurately, thereby limiting further disaster assessment. Hence, the multisource remote sensing and the POI data were used to disaggregate the 2012 prefecture-level WKS data into 1000 m × 1000 m grids. Subsequently, ensemble models were built via the stacking method. The performance of the ensemble models was verified by evaluating and comparing the three base models with the stacking model. The stacking model attained more robust prediction results (RMSE = 0.34, R2 = 0.9025), and its prediction spatially presented a realistic asset distribution. The 1000 m × 1000 m WKS gridded data produced by this research offer a more reasonable and accurate socioeconomic exposure map compared with existing ones, thereby providing an important bibliography for disaster assessment. This study may also be adopted by the ensemble learning models in refining the spatialization of the socioeconomic data.
Coastal wetlands provide essential ecosystem services, while usually experiencing land transformation or degradation mainly due to intense anthropogenic activities and climate changes. Understanding ...the changes in wetlands ecosystem services is essential to decision makers for generating sound coastal planning. Hangzhou Bay is rich in wetland resources, and the urbanization of Hangzhou Bay in the past three decades has caused fundamental changes in the wetlands in the region. Based on the remote sensing images of the Hangzhou Bay area from 1990 to 2020, this paper analyzes the land use situation of the Hangzhou Bay area in seven periods. This paper calculates the area transfer matrix of various types of wetlands. It uses the InVEST model to evaluate the changes in the function of wetland ecosystem services in the Hangzhou Bay area. Hangzhou Bay wetlands show a trend of transferring natural wetlands to artificial and non-wetlands from 1990 to 2020. Carbon stocks fell by 14.24%. The annual water production decreased by 33.93% and then returned to the original level. The area of habitat degradation increased by 79.94%. The main influencing factors are paddy field degradation, increase in non-wetland area, and decrease in sea area. This paper proposes that the development and construction of farmland in the “red line” area and established wetland reserves are prohibited, and to strengthen the training of wetland management personnel, establish a sound decision-making consultation mechanism, and increase the scientific research expenditure on wetlands in the region.
Coastline ecological restoration is a critical approach for improving the coastal ecological environment and natural disaster mitigation capacity. Zhejiang Province, with the longest coastline in ...China, has carried out a three-year action of coastline remediation and restoration, expecting to complete the 300-km coastline restoration by 2020 as part of China’s coastline restoration project. We developed a cost–benefit framework synthesizing the ecosystem services (ES) analysis pattern and input-output approach to evaluate Zhejiang’s coastline ecological restoration projects. The results showed that the average value of ecosystem services (VES) of coastline restoration in Zhejiang was approximately 11,829 yuan/m, which was lower than the average VES of natural coastline. Obviously, damaged natural coastline could cause VES degradation, which cannot make up for the loss in a short time. In an optimistic scenario, coastline ecological restoration projects would deliver enormous well-being to Zhejiang and even China. Our results suggested that making decisions should be based on the net value after accounting for costs (NES), because ignoring costs might mislead planners to overstate the perceived benefits. The study provided a realistic data basis and method for coastline restoration projects in terms of the design, implementation and effectiveness evaluation to achieve sustainable development.
Strengthening scientific research, technological capacity and sustainable use of oceans in developing countries are the goals of the UN’s 2030 Agenda for Sustainable Development. Marine science and ...education as the key foundation for achieving these goals has been seldom evaluated quantitatively and collectively. This paper adopted the DEA modelling from economics for analyzing the long-term input and output performance of marine science and education at a national scale in China both by region and discipline. It is found that China’s marine science and education level has been improving annually in the last decade. The input/output efficiency of science and education in 11 coastal provinces however has slightly declined except Guangdong. The input/output performance among 14 research disciplines was further evaluated and was found the similar improving trends. The input/output efficiency of 70% research disciplines showed an increasing trend while 30% of which showed a slightly declining trend. The results could provide important references for prioritizing the science and education resources allocation both in different coastal regions and marine research disciplines to save the investment and achieve more progress.
Marine natural capital is an important component of natural capital yields goods and service flows benefiting the human being. The emergy analysis method allows one to account for mass, energy and ...money flows in an ecosystem, providing technical support for assessing its broader value regarding our economic dependence. Thus, we used this method to evaluate the natural capital of the Zhoushan archipelago sea area from 2011 to 2016 and proposed a formula to estimate the marine organism’s transformity. The average total emergy of our study area was 6.93 × 1022 sej and emdollar was about 9.20 billion yuan, which is equivalent to 9.3% of the average regional GDP of 98.5 billion during the same period. The Zhoushan archipelago sea area has high emergy density (ED) and low emergy self-sufficiency ratio (ESR), which shows low input–output efficiency for local use. In addition, the high purchased emergy (PR), high emergy exchange ratio (EER) and low renewable resources emergy ratio (%R) imply an increasing dependence on the outside social and economic inputs. Overall, Zhoushan sea area was in an early but steady state of development. The results can serve as a benchmark for policy making and implementation to achieve local sustainable development. As a tool for emergy-based sea area capital assessment, the model is of great significance for quantifying the ecosystem service value and accounting for marine/land natural capital value.