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Understanding the spatial-temporal distribution of grazing livestock is crucial for assessing the sustainability of livestock systems, managing animal diseases, mitigating climate change risks, and controlling greenhouse gas emissions. In China, grazing ruminants are mostly distributed across the vast grasslands in semi-humid and alpine areas. However, existing datasets of gridded distribution of grazing ruminants in China do not distinguish grazing ruminants with other livestock production systems, nor capture their long-term and seasonal dynamics, and tend to overestimate grazing livestock distribution. This study uses the county-level data from the Grassland Ecological Protection Subsidies to differentiate grazing livestock from other forms of livestock rearing. Interpretable machine learning models were used to detect the seasonality of grazing pasture and map the C hina's l ong-term annual r uminant livestock d istribution in g razing l ivestock p roduction s ystems from 2000 to 2021 (CLRD-GLPS). The model's internal ten-fold cross-validation results (adjusted R2) for cattle ranged from 0.850 to 0.952 and for sheep from 0.780 to 0.836. External validation using province-level livestock meat production data yielded Pearson correlation coefficients of 0.83–0.88 for cattle and 0.92–0.94 for sheep, respectively. The CLRD-GLPS datasets provide more detailed, gridded information on local livestock distribution than census-based data. Compared to actual census data and the GLW datasets, they better capture the spatial-temporal dynamics of livestock distribution. Spatially, the largest cattle numbers on seasonal pastures were in the south-eastern edge of the Qinghai-Tibet Plateau (QTP), while the largest sheep numbers were in north-eastern Qinghai and Xinjiang. Temporally (2000–2021), cattle numbers increased near the Three-River Source National Park and Helan Mountains, while sheep numbers decreased on seasonal pastures on the QTP, with no significant changes on year-round pastures in Inner Mongolia. The datasets provide essential information for understanding the spatial-temporal dynamics of grazing ruminants and formulating relevant livestock management policies, among other applications. Additionally, the research framework developed in this study can serve as a new framework for creating livestock distribution datasets in other regions and livestock production systems. [ABSTRACT FROM AUTHOR]

Grasslands absorb and release carbon dioxide (CO2), emit methane (CH4) from grazing livestock, and emit nitrous oxide (N2O) from soils. Little is known about how the fluxes of these three greenhouse gases, from managed and natural grasslands worldwide, have contributed to past climate change, or the roles of managed pastures versus natural grasslands. Here, global trends and regional patterns of the full greenhouse gas balance of grasslands are estimated for the period 1750 to 2012. A new spatially explicit land surface model is applied, to separate the direct effects of human activities from land management and the indirect effects from climate change, increasing CO2 and regional changes in nitrogen deposition. Direct human management activities are simulated to have caused grasslands to switch from a sink to a source of greenhouse gas, because of increased livestock numbers and accelerated conversion of natural lands to pasture. However, climate change drivers contributed a net carbon sink in soil organic matter, mainly from the increased productivity of grasslands due to increased CO2 and nitrogen deposition. The net radiative forcing of all grasslands is currently close to neutral, but has been increasing since the 1960s. Here, we show that the net global climate warming caused by managed grassland cancels the net climate cooling from carbon sinks in sparsely grazed and natural grasslands. In the face of future climate change and increased demand for livestock products, these findings highlight the need to use sustainable management to preserve and enhance soil carbon storage in grasslands and to reduce greenhouse gas emissions from managed grasslands. Grasslands, and the livestock that live there, are dynamic sources and sinks of greenhouse gases, but what controls these fluxes remains poorly characterized. Here the authors show that on the global level, grasslands are climate neutral owing to the cancelling effects of managed vs. natural systems. [ABSTRACT FROM AUTHOR]

Climate change is threatening food security in many tropical countries, where a large proportion of food is produced by vulnerable smallholder farmers. Interventions are available to offset many of the negative impacts of climate change on agriculture, and they can be tailored to local conditions often through relative modest investments. However, little quantitative information is available to guide investment or policy choices at a time when countries and development agencies are under pressure to implement policies that can help achieve Sustainable Development Goals while coping with climate change. Among smallholder adaptation options, developing seeds resilient to current and future climate shocks expected locally is one of the most important actions available now. In this paper, we used national and local data to estimate the costs of climate change to smallholder farmers in Malawi and Tanzania. We found that the benefits from adopting resilient seeds ranged between 984 million and 2.1 billion USD during 2020–2050. Our analysis demonstrates the benefits of establishing and maintaining a flexible national seed sector with participation by communities in the breeding, delivery, and adoption cycle. [ABSTRACT FROM AUTHOR]

Communities across the Pacific are being challenged by the impacts of climate change. Attaining food and nutrition security goals is also a priority for the region, particularly in relation to improving dietary quality and reducing the incidence of non-communicable diseases. Addressing these challenges requires context-specific research that incorporates a realistic understanding of the links between drivers of change, food systems, and how these influence diets and health. Using a case study approach, this study explores links between climate hazards, food systems, and diets in remote coastal villages of Fiji. Livelihood transitions and climate hazards explain why households have become less reliant on local fisheries and agriculture for their dietary needs. Most households are routinely consuming only locally sourced food items from four food groups, meaning dietary diversity is low. In addition, diets are shifting and now include significant quantities of energy-dense processed (imported) foods with lower nutritional value. The study highlights the importance of increasing availability of fruits and vegetables, mainly through local production, and diversifying sustainable sources of animal protein as strategies to increase diet quality. These communities are already implementing strategies to adapt to climate change, yet this study underscores the need to link climate adaptation with changes to food systems and diets, in ways that allow livelihoods to be sustained and the quality of life of rural dwellers to improve. [ABSTRACT FROM AUTHOR]

Air change efficiency evaluates the ability of a system to achieve the change of the air contained in a confined interior space. It is conditioned by the geometry of the room, the different openings and the properties of the air among others. Rectangular rooms do not offer impediments when mixing the interior air; however, in rooms with non-regular shapes, stagnation phenomenon can occur in the corners. This paper proposes the study of the air change efficiency in an L-shaped room in which the position of the inlet and outlet openings is sequentially variated. This study is based on the execution of successive numerical simulations, validated by experimental studies. The results show that there are differences on the ventilation efficiency of up to 13.49% between the most dissimilar cases, which occur when one of the openings is located in a corner. If the other opening is placed nearby, the results are very poor; whereas if it is placed at the opposite corner, the efficiency value improves due to the circulation of the air through the room. When these openings are placed near the centre of the room, the efficiencies that are obtained are more similar and this analysis is less relevant. [ABSTRACT FROM AUTHOR]

It is widely accepted that current food systems are not on a trajectory for achieving the Sustainable Development Goals by the end of the decade. Technological innovation will have a considerable role to play in different parts of the food system; many promising options exist or are in the pipeline, some of which may be highly disruptive to existing value chains. Scaling up the innovations required, at the same time as protecting those who may lose out in the short term, will require a strong enabling environment. Here we apply an existing framework of eight change accelerators to six case studies of historical agricultural innovation. We estimated the degree to which each accelerator had been addressed at some stage in the innovation process, as a measure of the gap between what was needed and what was achieved. For the innovations that are being taken to scale and widely utilized, these accelerator gaps are small. Uptake of other innovations is stalled, and for these we found large gaps for one or more of the eight accelerators. Impactful innovation processes address all eight change accelerators at some point, with different phasing of the accelerators depending on the nature of the technology and on the impact pathway being pursued. This simple framework, when used in combination with narratives of uptake based on theories of change and impact pathways, may provide an effective means of screening future innovation processes to help prioritize and guide investment that can lead to more resilient, sustainable and equitable food systems. • Food system innovation will be needed to meet food security and environmental goals. • A framework of eight innovation accelerators was applied to six historical case studies. • The impactful case studies addressed all accelerators at some time during the innovation process. • The framework can help screen pipeline innovations to guide future investment. [ABSTRACT FROM AUTHOR]