Zhaoqing Yang

Bio: Zhaoqing Yang is an academic researcher from Pacific Northwest National Laboratory. The author has contributed to research in topics: Tidal power & Buoy. The author has an hindex of 22, co-authored 95 publications receiving 1272 citations. Previous affiliations of Zhaoqing Yang include University of Washington & Battelle Memorial Institute.

Drivers, trends, and potential impacts of long-term coastal reclamation in China from 1985 to 2010

Abstract: The reclamation of coastal land for agricultural, industrial, and urban land use—a common worldwide practice—has occurred extensively in the coastal region of China. In recent decades, all coastal provinces and metropolises in China have experienced severe coastal reclamation related to land scarcity caused by rapid economic growth and urbanization. However, the value of coastal wetlands and ecosystems has not been well understood and appreciated until recent development of advantageous methods of restoring reclaimed land to coastal wetlands in many developed countries. The overall objective of this study is to provide detailed spatial and temporal distributions of coastal reclamation; analyze drivers such as coastal economy, population growth, and urbanization; and understand the relationships among the drivers and land reclamation. We used long-term Landsat image time series from 1985 to 2010 in 5-year intervals, in combination with remotely sensed image interpretation and spatial analysis, to map the reclamation status and changes across the coastal region of China. The Landsat images time-series analysis was also conducted to evaluate the effects of the economy, population, and urbanization drivers on coastal reclamation. The analysis results indicated that 754,697 ha of coastal wetlands have been reclaimed across all coastal provinces and metropolises from 1985 to 2010, and the trend increased sharply after 2005. High-intensity coastal reclamation was mainly driven by the booming economy, especially after 2000, associated with urbanization and industrial development in China's coastal region; this was closely correlated with the gross domestic product (GDP) per capita. The continuous large-scale coastal reclamation of its coastal region now means China is facing a great challenge, including the enormous loss of vegetated coastal wetlands, negative environmental effects, and potential disaster risks related to coastal flooding under future change climate conditions. Long-term ecosystem-based coastal protection and management are critical to support sustainable coastal ecosystems in China in the future.

Estuarine response to river flow and sea-level rise under future climate change and human development

Abstract: Understanding the response of river flow and estuarine hydrodynamics to climate change, land-use/land-cover change (LULC), and sea-level rise is essential to managing water resources and stress on living organisms under these changing conditions. This paper presents a modeling study using a watershed hydrology model and an estuarine hydrodynamic model, in a one-way coupling, to investigate the estuarine hydrodynamic response to sea-level rise and change in river flow due to the effect of future climate and LULC changes in the Snohomish River estuary, Washington, USA. A set of hydrodynamic variables, including salinity intrusion points, average water depth, and salinity of the inundated area, were used to quantify the estuarine response to river flow and sea-level rise. Model results suggest that salinity intrusion points in the Snohomish River estuary and the average salinity of the inundated areas are a nonlinear function of river flow, although the average water depth in the inundated area is approximately linear with river flow. Future climate changes will shift salinity intrusion points further upstream under low flow conditions and further downstream under high flow conditions. In contrast, under the future LULC change scenario, the salinity intrusion point will shift downstream under both low and high flow conditions, compared to present conditions. The model results also suggest that the average water depth in the inundated areas increases linearly with sea-level rise but at a slower rate, and the average salinity in the inundated areas increases linearly with sea-level rise; however, the response of salinity intrusion points in the river to sea-level rise is strongly nonlinear.

Impacts of coastal reclamation on wetlands: Loss, resilience, and sustainable management

Abstract: Coastal wetlands are some of the most valuable ecosystems on Earth because they provide many ecological services for coastal security. However, these wetlands are seriously threatened by accelerated climate change and intensive anthropogenic activities. To understand the impacts of land reclamation on landscape change of coastal wetlands and the long-term effects of disturbances of coastal wetlands on their sustainable management, we used time-series Landsat imagery with an object-oriented classification and Digital Shoreline Analysis System to map wetland changes within a reclaimed area in the Pudong District (PD), in Shanghai, China. Our analysis indicated that from 1989 to 2013, 19,793.4 ha of coastal wetlands have been changed to inland wetlands enclosed by a seawall and dike since 1989, thereby cutting off the exchange of sediment and water flux between the wetlands and the coastal ocean. Subsequently, under the increasing threats of anthropogenic activities, the wetland ecosystem collapsed sharply, in a transformation chain of inland wetland (fresh swamp), artificial wetland (agriculture and aquaculture wetland), and non-wetland (urban land). Under this explosive utilization following coastal reclamation, only 8.9% of natural wetlands remain in the reclaimed area, which has experienced an average annual wetland loss rate of 3.8% over the past 24 years. More than 80% of the wetlands have been developed for agricultural, industrial, and urban land uses, leading to an enormous loss of associated ecological services—benefits arising from the ecological functions provided by wetland ecosystems, thereby undermining the coastal protection these wetlands provided. Nevertheless, considerable regeneration of wetlands occurred because of their inherent resilience. This paper addresses the importance of maintaining a balance between economic growth and coastal ecological protection for sustainable management. It proposes a strategy for how ecosystem-based land planning and ecological engineering should be applied to ensure the effective and sustainable management of living shorelines so that the benefits of healthy ecological functions accrue to coastal ecosystems.

Global trends in wind speed and wave height over the past 25 years

Abstract: Wind speeds over the world’s oceans have increased over the past two decades, as have wave heights. Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed and the surface gravity waves generated by such winds play an important role. We used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in oceanic wind speed and wave height over this period. We find a general global trend of increasing values of wind speed and, to a lesser degree, wave height, over this period. The rate of increase is greater for extreme events as compared to the mean condition.

Impacts of 1.5°C Global Warming on Natural and Human Systems

Abstract: Lead Authors: Marco Bindi (Italy), Sally Brown (UK), Ines Camilloni (Argentina), Arona Diedhiou (Ivory Coast/Senegal), Riyanti Djalante (Japan/Indonesia), Kristie L. Ebi (USA), Francois Engelbrecht (South Africa), Joel Guiot (France), Yasuaki Hijioka (Japan), Shagun Mehrotra (USA/India), Antony Payne (UK), Sonia I. Seneviratne (Switzerland), Adelle Thomas (Bahamas), Rachel Warren (UK), Guangsheng Zhou (China)

The Blue Acceleration: The Trajectory of Human Expansion into the Ocean

Abstract: Does humanity's future lie in the ocean? As demand for resources continues to grow and land-based sources decline, expectations for the ocean as an engine of human development are increasing. Claiming marine resources and space is not new to humanity, but the extent, intensity, and diversity of today's aspirations are unprecedented. We describe this as the blue acceleration—a race among diverse and often competing interests for ocean food, material, and space. Exploring what this new reality means for the global ocean and how to steer it in a sustainable and equitable way represents an urgent challenge.

Drivers, trends, and potential impacts of long-term coastal reclamation in China from 1985 to 2010

Abstract: The reclamation of coastal land for agricultural, industrial, and urban land use—a common worldwide practice—has occurred extensively in the coastal region of China. In recent decades, all coastal provinces and metropolises in China have experienced severe coastal reclamation related to land scarcity caused by rapid economic growth and urbanization. However, the value of coastal wetlands and ecosystems has not been well understood and appreciated until recent development of advantageous methods of restoring reclaimed land to coastal wetlands in many developed countries. The overall objective of this study is to provide detailed spatial and temporal distributions of coastal reclamation; analyze drivers such as coastal economy, population growth, and urbanization; and understand the relationships among the drivers and land reclamation. We used long-term Landsat image time series from 1985 to 2010 in 5-year intervals, in combination with remotely sensed image interpretation and spatial analysis, to map the reclamation status and changes across the coastal region of China. The Landsat images time-series analysis was also conducted to evaluate the effects of the economy, population, and urbanization drivers on coastal reclamation. The analysis results indicated that 754,697 ha of coastal wetlands have been reclaimed across all coastal provinces and metropolises from 1985 to 2010, and the trend increased sharply after 2005. High-intensity coastal reclamation was mainly driven by the booming economy, especially after 2000, associated with urbanization and industrial development in China's coastal region; this was closely correlated with the gross domestic product (GDP) per capita. The continuous large-scale coastal reclamation of its coastal region now means China is facing a great challenge, including the enormous loss of vegetated coastal wetlands, negative environmental effects, and potential disaster risks related to coastal flooding under future change climate conditions. Long-term ecosystem-based coastal protection and management are critical to support sustainable coastal ecosystems in China in the future.