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• This paper aimed to investigate the interactions between land use cover (LUC) and climate change (CC). • The results showed that the interactions between LUC and CC are both direct and indirect. • Arable and rangeland use changes affect CO2 emission in both direct and indirect ways. • Rising rangelands and reducing forest areas have indirectly increased surface temperature. • CC mitigation policies should be followed by considering both direct and indirect effects. Humanity deals with several challenges in this century such as climate change, land use, and land use/cover change (LUCC). Determining the patterns, developments, and consequences of LUCC issues for the livelihoods of people, especially poor people, is very important. Therefore, this paper aims to investigate the interactions between LUCC and climate change over the period of 1966–2015 (50 years) as a complex system at the global level. CO 2 emissions and surface temperature are considered as the main indicators of climate change (CC). The data were analyzed in time-oriented (time-based) and local or place-oriented (country-based) manners. The results showed that arable and rangeland use changes (LUC) affect CO 2 emissions in both direct and indirect ways. However, the direct effect of rangeland use change is positive, and its indirect effect is negative. In addition, deforestation has increased CO 2 emissions indirectly. LUCC can also change the ability of the ecosystem to deliver services to people, including biodiversity and other resources such as food, fiber, water, etc. Therefore, it is critical to determine the patterns, trends, and impacts of LUCC on CC. Thus, CC mitigation policies should be followed by considering both direct and indirect effects. Without a doubt, this will be realized when the decision and policymakers have a better understanding of the structure and interaction between CC, LUCC, and their components as a whole system. [ABSTRACT FROM AUTHOR]

• Assessing spatio-temporal changes in eco-environmental by Gini coefficient and Kernel density estimation method. • Eco-environmental risks are marked by high east and low west and clustered in blocks. • Spatial variability of eco-environmental risks in the study area is narrowing. • High risk and low risk provinces in the Yangtze River Delta region proximity distribution. • Policymakers should govern eco-environmental risks from a synergistic perspective. The Yangtze River Economic Belt is an essential ecological security barrier and demonstration area for ecological civilization construction in China, so it is vital to prevent and resolve eco-environmental risks for its healthy development. However, the state of the development of eco-environmental risks in this region has remained understudied. Based on panel data from 2000 to 2020, this paper analyzes the development status of eco-environmental risks in the Yangtze River Economic Belt using the Dagum Gini coefficient, kernel density estimation, and Moran's I test model. The results show that: (1) the eco-environmental risk index of the Yangtze River Economic Belt ranges from 50.25 to 92.16, which represents a high risk status overall, showing obvious characteristics of a high index in the east and a low index in the west. (2) The overall Gini coefficient of eco-environmental risks in the Yangtze River Economic Belt decreased from 0.059 in 2000 to 0.0502 in 2020, showing an obvious M-type evolution trend. The internal difference in eco-environmental risks of the lower reaches is the largest, followed by those of the upper and middle reaches. The average Gini coefficient in the upper and the lower reaches is 0.0679, while that in the middle and the lower reaches is 0.0645, and that in the upper and the middle reaches is 0.0604. The average contribution rates of inside reaches, different reaches, and hypervariable density in the study cycle are 29.55%, 27.84%, and 42.61%. (3) The kernel density estimation curve of eco-environmental risks in the study area shifts from the lower reaches to the middle and upper reaches, with low-risk areas adjacent to high-risk areas, especially in Zhejiang, Jiangsu, Anhui, and Shanghai, where the high–low/low–high clustering characteristics are more significant. Finally, we put forward some policy implications to provide practical support for the sustainable development of the Yangtze River Economic Belt eco-environment. [ABSTRACT FROM AUTHOR]

• Recent research on the B&R eco-environment is reviewed. • The B&R is likely to face environmental challenges due to its fragile background. • Four key aspects of the ecological environment are studied. • Sustainable development should be promoted under socioeconomic frameworks for the B&R. • Future research directions for improving the B&R eco-environments are proposed. The Belt and Road Initiative (BRI) will play an essential role in boosting the world's economy. However, the main portion of the Belt and Road (B&R) is in arid, semi-arid, or sub-humid fragile ecological regions, which with global climate change and the intensification of human activities will face many pressing environmental challenges in the future. Despite this, in the existing research on the B&R, papers in the field of natural sciences are less than 1.2–4.3% of the total number of papers on the main databases, which is far lower than the coverage in humanities and social sciences. And those focused on the ecological and environmental issues along the B&R are even fewer, so necessary understanding of both the risks and adequate mitigation measures remains unclear. This paper systematically reviews the relevant research on the eco-environments along the B&R, and summarizes it in terms including of spatial patterns and cognition, cost efficiency and evaluation, ecological security and evaluation, ecological footprint and carrying capacity. It further suggests that a better understanding of environmental changes and their effects on the B&R is needed. Additionally, it is essential that the potential positive socio-economic impacts for the future under the BRI are sustainable. Finally, future research directions are proposed to improve for the better eco-environments in B&R regions with consideration of global changes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Current land management can lead to more severe BAP conditions. • Regulating fertilizer application rate can offset HAB risks from extreme climate. • Regulating P was more effective in reducing HAB risks in freshwater watersheds. • Regulating N was more effective in controlling HAB downstream of watershed. This paper was aimed at assessing the risk of HAB occurrence in a highly cultivated watershed and evaluating the effectiveness of N and P fertilizer reduction practices in mitigating this risk under future climate projections. To achieve this objective, a modelling framework was developed for HAB risk assessment under different environmental stressors including climate changes and different land management practices. The modelling framework used a fully distributed physical-based hydrologic model, MIKE SHE, and a hydrodynamic river model, MIKE 11, coupled with ECO-Lab to simulate the fate and transport of different forms of N and P in the Upper Sangamon River Basin (USRB), a highly cultivated watershed in central Illinois. Three different land management scenarios based on the N and P reduction target in "The Gulf Hypoxia Action Plan" were simulated to assess the P nonpoint source behavior and HAB risk level in the USRB from 2020 to 2050 under extreme climate projections. Our results predicted that the HAB risk in USRB is relatively low even with increased bioavailable P (BAP) concentration and longer duration with high BAP concentration due to low water temperature. Reducing N or P application rates by 50% was able to offset the negative effects on HAB occurrence from extreme climate projections apart from spring. Within P and N, regulating P was found to be more effective in reducing HAB risks in the USRB while regulating N was more effective in controlling HAB downstream. Understanding the dynamics of N and P in causing the occurrence of HAB was expected to improve the mitigation measures that we implement at the field level. [ABSTRACT FROM AUTHOR]