Carbon budget accounting relies heavily on Food and Agriculture Organization land-use data reported by governments. Here we develop a new land-use and cover-change database for China, finding that differing historical survey methods biased China’s reported data causing large errors in Food and Agriculture Organization databases. Land ecosystem model simulations driven with the new data reveal a strong carbon sink of 8.9 ± 0.8 Pg carbon from 1980 to 2019 in China, which was not captured in Food and Agriculture Organization data-based estimations due to biased land-use and cover-change signals. The land-use and cover-change in China, characterized by a rapid forest expansion from 1980 to 2019, contributed to nearly 44% of the national terrestrial carbon sink. In contrast, climate changes (22.3%), increasing nitrogen deposition (12.9%), and rising carbon dioxide (8.1%) are less important contributors. This indicates that previous studies have greatly underestimated the impact of land-use and cover-change on the terrestrial carbon balance of China. This study underlines the importance of reliable land-use and cover-change databases in global carbon budget accounting.

Biodiversity losses can lead to global environmental crisis. Humans utilize biodiversity for a variety of ecosystem services. However, what drives biodiversity losses have become a critical question during the 21st century. Lately, the Hindu Kush Himalayan (HKH) region in Asia, one of the world’s pristine habitats with the origin of majestic river systems including Brahmaputra, Indus, Mekong, and Yangtze, has witnessed rapid climatic warming. The unprecedented rates of climate warming in HKH has threatened biodiversity losses, ecosystem functioning and ecosystem services, and consequently the existence of mankind in the region. The Intergovernmental Panel on Climate Change (IPCC) and the Intergovernmental Science and Policy Platform on Biodiversity and Ecosystem Services (IPBES) highlight the risks to humanity arising from unsustainable use of natural resources and loss of biodiversity worldwide under rapid climate warming condition. In addition, the growing economic transformation in HKH can have high environmental costs and biodiversity losses. By realizing this fact, the Convention on Biological Diversity addresses the key issues of biodiversity and ecosystem services in the HKH by liaising with the United Nations Framework Convention on Climate Change, Paris Agreement, and the Sustainable Development Goals (SDGs). Hence, the challenges of biodiversity losses, poor ecosystem functioning followed by reduced ecosystem services posed by climate warming and anthropogenic impacts needs to be addressed urgently by countries and multilateral agencies in HKH by identifying threatened ecosystem services and by providing better sustainability solutions. Here, I have outlined the current state of Himalayan biodiversity and ecosystem function and developed a framework for resilience management with an integrated approach of science and society to advance knowledge through learning. The resilience framework offers practical solutions comprising a robust and harmonized monitoring of climatic data, the use of multi-indicator approaches and modelling, and to make collaborated efforts among policy makers, implementers, and analysts to tackle evolving losses of biological diversity and reduction in ecosystem services in the HKH region.

Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeolimnological records. While the effects of humans at the landscape level are relatively easily demonstrated, the earliest signals of human-induced changes in the structure and functioning of aquatic ecosystems need very careful investigation using multiple proxies. Additional studies will improve our understanding of linkages between human settlements, their exploitation of land and water resources, and the downstream effects on continental waters.

China ranks in the highest position for nitrogen (N) fertilizer consumption in the world. Although N fertilizer use has greatly contributed to the China's food production, this has also caused an unprecedented alteration in the biogeochemical cycles and endangered terrestrial and aquatic ecosystems. Existing use of N fertilizers in China, as shown by digital maps, is usually coarse in resolution and intermittently covered with a biased gridded dataset. Here, we have reconstructed a historical, annual N fertilizer use dataset in China and resampled it to 5 km×5 km resolution, covering the period from 1952 to 2018 by integrating improved cropland maps. Results showed that most of the N input was directly applied as N-only fertilizer, while the contribution from compound fertilizers has ranged between 16 % and 24 % since 1980. The national total N fertilizer input increased from 0.06 Tg N yr⁻¹ (0.05 g N m⁻² yr⁻¹) in 1952 to 31.15 Tg N yr⁻¹ (18.83 g N m⁻² yr⁻¹) in 2014 and then decreased to 28.31 Tg N yr⁻¹ (17.06 g N m⁻² yr⁻¹) in 2018. Despite the total N input decreasing by 9.1 % (2.84 Tg N yr⁻¹) from 2014 to 2018, the N input from compound fertilizers has increased by 6 % (0.43 Tg N yr⁻¹) during the corresponding period. The previous Food and Agriculture Organization (FAO) data-based N fertilizer products in China overestimated N use in low cropland coverage areas but underestimated N use in high cropland coverage areas. However, our newly reconstructed data have not only corrected the existing biases and improved the spatial distribution but have also shown that vegetable and other crops (e.g., orchards), but not grain crops, are the most intensively fertilized crops in China, implying the importance of quantifying greenhouse gas (GHG) emissions from these croplands. We argue that the reconstructed, spatially explicit N fertilizer use data in this study are expected to contribute to better understanding of biogeochemical cycles, including the simulations of GHG emissions and food production in China. The spatially explicit N fertilizer use and the crop-specific N fertilizer use datasets are available via an open data repository (https://doi.org/10.6084/m9.figshare.21371469.v1; Yu, 2022).

Land evaporation (ET) plays a crucial role in the hydrological and energy cycle. However, the widely used model-based products, even though helpful, are still subject to great uncertainties due to imperfect model parameterizations and forcing data. The lack of available observed data has further complicated estimation. Hence, there is an urgency to define the global proxy land ET with lower uncertainties for climate-induced hydrology and energy change. This study has combined three existing model-based products – the fifth-generation ECMWF reanalysis (ERA5), Global Land Data Assimilation System Version 2 (GLDAS2), and the second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) – to obtain a single framework of a long-term (1980–2017) daily ET product at a spatial resolution of 0.25^∘. Here, we use the reliability ensemble averaging (REA) method, which minimizes errors using reference data, to combine the three products over regions with high consistencies between the products using the coefficient of variation (CV). The Global Land Evaporation Amsterdam Model Version 3.2a (GLEAM3.2a) and flux tower observation data were selected as the data for reference and evaluation, respectively. The results showed that the merged product performed well over a range of vegetation cover scenarios. The merged product also captured the trend of land evaporation over different areas well, showing the significant decreasing trend in the Amazon Plain in South America and Congo Basin in central Africa and the increasing trend in the east of North America, west of Europe, south of Asia and north of Oceania. In addition to demonstrating a good performance, the REA method also successfully converged the models based on the reliability of the inputs. The resulting REA data can be accessed at https://doi.org/10.5281/zenodo.4595941 (Lu et al., 2021).

Global freshwaters are severely depleted. Provision of improved water infrastructure technologies and innovation can address challenges posed by water shortages to environmental sustainability. China’s South-to-North Water Diversion Project has generated extensive debates over sustainability of water resources system in the northern drier region, which faces severe water scarcity hindering ecosystems, agriculture, industries and livelihoods. Some arguments extend the views that large infrastructure projects can have negative implications for biodiversity conservation and ecosystem goods and services. However, this study strengthens the opposite view, as such projects would resolve increasing environmental challenges northern China has been facing over many decades due to severe water shortages. The project empowers connectivity among individuals, community, and organizations that the sustainability of goods and services such as energy, irrigation and water supply are perceived, and livelihoods and the standard of peoples’ living is improved. A resilient, robust and adaptive water infrastructure framework can overcome the challenges of water shortages by meeting a long term social, economic and environmental goals for water resources systems in northern China. Such framework can also identify the thresholds of change and the threats associated with environmental sustainability.