Future Changes Research Articles

Impact of Future Climate Change on Energy Consumption in Residential Buildings: A case study for representative cities in Japan

This study examines the impact of future climate change on energy consumption in residential buildings in Japan, taking into account both the current and future typical meteorological year (TMY) database. TMY data is widely used in the building sector for energy performance assessments, system sizing, and optimization. To investigate the impact of current and future TMY databases on energy consumption of buildings, the study predicts the cooling and heating loads of residential buildings in four cities of Japan under the current (2020 ver.) and future (2086 ver.) TMY databases. Results show that the use of future TMY database leads to significant changes in air-conditioning heat loads of residential buildings in Japan. It finds that the annual cooling load in residential buildings of four cites of Japan increases by approximately 12% for Tokyo, approximately 9% for Toyohashi, approximately 8% for Osaka, and approximately 7% for Nagoya, respectively, however the annual heating load decreases by approximately 8% for Tokyo, approximately 9% for Toyohashi, approximately 6% for Osaka, and approximately 5% for Nagoya, respectively, compared to the current TMY database. This finding suggests that climate change will have a significant impact on future building energy consumption, and proposes energy-efficient building design as a solution to mitigate the impact of climate change on building energy consumption.

How will permafrost carbon respond to future climate change? A new assessment for future thaw trends of permafrost carbon on the Tibetan Plateau

Permafrost degradation on the Tibetan Plateau (TP) is anticipated to result in the thaw of permafrost carbon. Existing studies have been conducted to assess the future thaw of frozen carbon on the TP, primarily focusing on the deepening of the active layer while neglecting the impact of permafrost area shrinkage. This oversight may lead to a significant underestimation of the potential thaw of frozen carbon. Our research underscores the pivotal role of permafrost area shrinkage in estimating the future thaw of frozen carbon. Our findings reveal that when the combined effects of permafrost area shrinkage and active layer deepening are considered, the thaw rates of frozen carbon in various radiative forcing scenarios are nearly four times those based on active layer deepening alone. Notably, our results demonstrate substantial thaw of frozen organic carbon in the TP permafrost area under all four future scenarios: In the low radiative forcing scenario SSP1-2.6, it is predicted that 55.4 % of the organic carbon in the permafrost area 0–10 m soils will be in a state of thaw by 2100, and more than 90 % in the high radiative forcing scenario SSP5-8.5. This substantial thaw is poised to diminish the TP's current carbon sink function significantly. Our study emphasizes that as global warming persists, frozen carbon in permafrost areas will play a more active role in global carbon cycle processes in the future. Furthermore, we stress the importance of considering permafrost area shrinkage in understanding the thaw of frozen carbon, providing valuable insights for carbon balance studies on the TP.

Using ancient sedimentary DNA to forecast ecosystem trajectories under climate change.

Ecosystem response to climate change is complex. In order to forecast ecosystem dynamics, we need high-quality data on changes in past species abundance that can inform process-based models. Sedimentary ancient DNA (sedaDNA) has revolutionised our ability to document past ecosystems' dynamics. It provides time series of increased taxonomic resolution compared to microfossils (pollen, spores), and can often give species-level information, especially for past vascular plant and mammal abundances. Time series are much richer in information than contemporary spatial distribution information, which have been traditionally used to train models for predicting biodiversity and ecosystem responses to climate change. Here, we outline the potential contribution of sedaDNA to forecast ecosystem changes. We showcase how species-level time series may allow quantification of the effect of biotic interactions in ecosystem dynamics, and be used to estimate dispersal rates when a dense network of sites is available. By combining palaeo-time series, process-based models, and inverse modelling, we can recover the biotic and abiotic processes underlying ecosystem dynamics, which are traditionally very challenging to characterise. Dynamic models informed by sedaDNA can further be used to extrapolate beyond current dynamics and provide robust forecasts of ecosystem responses to future climate change. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.

Projected future climatic forcing on the global distribution of vegetation types.

Most emissions scenarios suggest temperature and precipitation regimes will change dramatically across the globe over the next 500 years. These changes will have large impacts on the biosphere, with species forced to migrate to follow their preferred environmental conditions, therefore moving and fragmenting ecosystems. However, most projections of the impacts of climate change only reach 2100, limiting our understanding of the temporal scope of climate impacts, and potentially impeding suitable adaptive action. To address this data gap, we model future climate change every 20 years from 2000 to 2500 CE, under different CO2 emissions scenarios, using a general circulation model. We then apply a biome model to these modelled climate futures, to investigate shifts in climatic forcing on vegetation worldwide, the feasibility of the migration required to enact these modelled vegetation changes, and potential overlap with human land use based on modern-day anthromes. Under a business-as-usual scenario, up to 40% of terrestrial area is expected to be suited to a different biome by 2500. Cold-adapted biomes, particularly boreal forest and dry tundra, are predicted to experience the greatest losses of suitable area. Without mitigation, these changes could have severe consequences both for global biodiversity and the provision of ecosystem services. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.

The Price Trend of Polypropylene

Since the polypropylene (PP) is one of the most widely used plastics, the futures prices of polypropylene are of great significance for studying the Chinese plastic market and related investors. This paper analyzes the factors that influence the changes in PP futures prices during and before the pandemic period by examining the correlation between upstream raw materials, downstream product markets, and PP futures prices. The results show that the futures prices of the raw materials are positively correlated with PP futures prices. Additionally, during the COVID-19 pandemic, due to the reduction in domestic PP demand in China, blocked crude oil imports, and refinery closures caused by control measures, the impact of crude oil futures prices on PP futures prices is relatively diminished. Furthermore, the increased demand for plastic packaging during the pandemic led to abnormal fluctuations in the packaging stock index, making it less valuable for analyzing PP futures prices. Finally, a regression analysis is conducted to establish a generalized predictive model for PP futures prices during non-pandemic periods, which is 9.91469 * crude oil futures prices + (-1.22343) * packaging stock index + 3.96203 * textile stock index + (-0.26201) * medical devices stock index. Its reliability is tested using data tests, residual vs. fitted analysis, and K-fold cross-validation, among other methods.

Is Chinese Medicine Facing a Potential Workforce Crisis in Australia? Demographic Changes in the Profession over the Last Decade.

Background: As a prominent part of complementary and alternative medicine, Chinese Medicine (CM) has proved its strengths in treating a diverse range of acute and chronic medical conditions and is at present recognized in 196 countries and territories worldwide. In 2012, Australia regulated the CM profession under the National Regulation and Accreditation Scheme (NRAS) by legislation and reports quarterly demographic information about individual CM practitioners so to ensure public interest, although research examining the change of CM workforce in Australia has been scarce. Objective: This study aims to investigate the construction of the CM workforce in Australia and more importantly, evaluated its development in the last decade to capture the trajectory and trend in the present period and future potential changes. Methods: Data were sourced from the Australian Health Practitioner Regulation Agency (AHPRA) annual reports and the Chinese Medicine Board of Australia (CMBA) registration statistics from 2012 to 2023. A descriptive analysis was conducted with demographic variables, including profession, age, and gender, and chi-square tests and linear regression modeling were carried out to assess the variations between regions and across years. Results: The population of CM practitioners in 2022/2023 stagnated with slight decrease to 4,823, in contrast to the increase rate of 2.9% in the whole health care community. The number of young CM registrants (<35 y) shrank by 37.5% from 691 in 2012 to 432 in 2023. In comparison with other health care professions, CM comprises the smallest proportion of the population aged younger than 25 (0.2%) and the largest proportion aged older than 65 years (16.2%), advancing into an aging era. Conclusions: This study indicates a worrying potential decline in CM workforce in Australia, which is likely to be further exacerbated by the lack of new graduates and rise of median age among practitioners. Meanwhile, continued advancement in Western medicine technology and standards requires substantial efforts to increase both a better understanding of CM and demonstration of its efficacy. Furthermore, greater effort is needed to recruit and educate new young CM practitioners in Australia and to broaden the international training pipeline for a sustainable development of CM practice.

The impact of future UK offshore wind farm distribution and climate change on generation performance and variability

The UK plans to significantly increase offshore wind generation capacity as part of the effort to achieve net zero targets. Current installation is densely located in a few areas, particularly off the east coast of England, and although current siting proposals include new offshore regions, significant volumes of wind generation capacity are yet to be located to meet 2050 installation targets. This paper uses a recent dataset of multi-decadal offshore wind power capacity factor timeseries to assess how UK offshore wind generation is likely to be affected by both the spatial distribution of future wind farms, and by the impacts of near-future (2020–2050) climate change. We determine that a wider geographic spread of offshore capacity results in a much-improved and less-variable UK-aggregated power generation profile, with substantial reductions in periods of low generation and extreme wind power ramping events, without negatively impacting mean or peak generation outputs. The impact of near-term climate change appears to be minor, slightly reducing overall generation and possibly resulting in an underestimation of future installation requirements, but this climate signal is outweighed by the effects of spatial distribution, and even more so by inherent hourly to inter-annual wind speed variability. This study implies that the intermittency of wind generation can be partly mitigated through increasing the spatial diversity of the existing wind farm distribution. Alongside a more in depth investigation of future climate change, and a holistic assessment of relevant geospatial factors such as Levelised Cost of Energy, infrastructure, and environmental constraints, this study could be used for optimisation of future offshore wind siting.

Ecological Studies of Saurashtra Coast and Neighbouring Islands: IV. Piram Island

The Plant ecology of Piram, a small narrow off shore island situated 21°36':72°21' in the Gulf of Cambay is presented in this paper. Based on habitat, substratum and edaphic features the plant communities of the island have been distinguished into 7 main categories under three vegetational zones. 74 species are enumerated and the flora resembles the one on mainland. The first ecologically annotated list of Vascular plants will form a background for a study of future changes.

Drought in the middle growing season inhibited carbon uptake more critical in an anthropogenic shrub ecosystem of Northwest China

Large-scale ecological restoration efforts of the degraded desert steppe ecosystem in northwestern China have effectively combated desertification but have also resulted in the encroachment of shrubs. However, the function of the anthropogenic shrub ecosystem is still unknown under climate change, especially the response of carbon fluxes to drought, which hinders our further understanding of its sustainability in the future. Hence, based on the eddy covariance and environment sensors, continuous carbon and water fluxes and biophysical factors were monitored during 2019–2022 to investigate the characteristics of carbon fluxes and their response to seasonal drought in an anthropogenic shrub ecosystem dominated by Caragana liouana in the southern Mu Us sandy land, northwestern China. The results showed the shrub ecosystem was a stable carbon sink over the 4 years despite large interannual variability, with annual net ecosystem production (NEP) ranging from 54.37 to 150.35 g C·m−2·y−1. Interannual variability in NEP was mainly due to variation in gross primary productivity (GPP), which is driven by the fact that interannual variability in GPP was higher than interannual variability in ecosystem respiration (Reco). While drought inhibited GPP more than Reco, thus weakening the carbon sequestration ability of the ecosystem during the middle growing season, and thereby carbon fluxes in the shrub ecosystem were significantly suppressed by drought in the middle growing season but slightly in the early growing season. Furthermore, the magnitude and variation of carbon fluxes were determined by the maximum apparent photosynthetic capacity of the canopy (Pmax), leaf area index (LAI), and canopy conductance (gc), all of which are limited by water stress during drought. The work suggests that to keep the carbon sink of anthropogenic shrub ecosystems in arid and semi-arid areas, managers should focus on drought-relief measures in the middle growing season that are better adapted to future climate change.

Soil warming effects on the transpiration of trees and shrubs in a subtropical secondary forest: A manipulative experiment

The climate warming can increase the productivity of some species while decrease that of others, therefore, knowledge of species-specific responses to warming is helpful to understand the possible trajectory of forest ecosystems. Despite the importance of the subtropical secondary broadleaf forests developed from afforestation in South China, our understanding of how the transpiration of trees and shrubs co-growing in these forests responds to soil warming is limited. To explore the effects of soil warming on transpiration and associated ecophysiological traits of trees and shrubs in wet and dry seasons, as well as to clarify respective contributions of trees and shrubs transpiration to the stand total, we conducted a manipulative experiment of soil warming (+2 ℃, WA) and control (CK) in a subtropical secondary broadleaf forest in South China, and continuously monitored the transpiration (based on sap flow) of trees, Schima superba and Acacia auriculiformis, and that (derived from leaf temperature and microclimate) of shrubs, Psychotria asiatica and Castanopsis chinensis, from 2021 to 2022. We also measured leaf water potentials, leaf nutrient status, and δ13C-derived intrinsic water use efficiency (WUEi). Soil warming did not significantly alter the transpiration of trees, with the exception of A. auriculiformis in 2022, whereas it notably increased transpiration of both shrubs. We attributed the stimulation of shrubs’ transpiration mainly to the more favorable leaf water potentials under warming condition. Due to the increased transpiration, the contribution of shrubs to stand transpiration was consequently increased, highlighting the potential role of shrubs in the hydrological dynamics of forest ecosystems. Additionally, the WUEi, soil main macro-nutrients, and leaf nutritional status of all species were not significantly affected by soil warming. These findings indicated that the carbon-water exchange and nutrient status of the studied plants can be maintained even when exposed to moderate increases in soil temperature and relatively drier condition, reflecting the resilience of the subtropical secondary broadleaf forest to possible climate warming. Further research on the interaction and competition of co-existing trees and shrubs under soil warming will improve the prediction of forest dynamics under future climate change, which benefits the efforts to conserve such forests in order to address the environmental pressure in the region.

Modeling Environmental Vulnerability for 2050 Considering Different Scenarios in the Doce River Basin, Brazil

Understanding climate change and land use impacts is crucial for mitigating environmental degradation. This study assesses the environmental vulnerability of the Doce River Basin for 2050, considering future climate change and land use and land cover (LULC) scenarios. Factors including slope, elevation, relief dissection, precipitation, temperature, pedology, geology, urban distance, road distance, and LULC were evaluated using multicriteria analysis. Regional climate models Eta-HadGEM2-ES and Eta-MIROC5 under RCP 4.5 and RCP 8.5 emission scenarios were employed. The Land Change Modeler tool simulated 2050 LULC changes and hypothetical reforestation of legal reserve (RL) areas. Combining two climate and two LULC scenarios resulted in four future vulnerability scenarios. Projections indicate an over 300 mm reduction in average annual precipitation and an up to 2 °C temperature increase from 2020 to 2050. Scenario 4 (RCP 8.5 and LULC for 2050 with reforested RLs) showed the greatest basin area in the lowest vulnerability classes, while scenario 3 (RCP 4.5 and LULC for 2050) exhibited more high-vulnerability areas. Despite the projected relative improvement in environmental vulnerability by 2050 due to reduced rainfall, the complexity of associated relationships must be considered. These results contribute to mitigating environmental damage and adapting to future climatic conditions in the Doce River Basin.

Combining species distribution models and big datasets may provide finer assessments of snakebite impacts.

Snakebite is a major poverty-related neglected tropical disease. An integrated scientific approach is needed to understand the dynamics of this important health issue. Our objective was to estimate snakebite occurrence in a tropical area by using a blend of ecological modelling and robust statistical analysis. The present study used climatic, environmental, and human population density data to determine the area with snakebite occurrence-probability for the first time in Bangladesh. We also analysed a large, 16-year dataset of hospitalized snakebite cases to reveal the epidemiology of snakebite in the south-eastern zone of the country. Our results show that cobra bite is the most commonly occurring venomous snakebite in humans (around ~12% of the total yearly snakebite records), and men are more frequently bitten than women (2/3 of human victims are men). Most bites occur during the rainy season for cobra and green pit viper, while krait bites are not restricted to any particular season. As snakebite incidents are closely related to climate conditions, we can model snakebite risk using temperature and precipitation variables. Whereas there is a lack of snakebite reports from several parts of the study area in official records, our models predict that the entire study area is favourable for snakebite incidents. Based on the combined evidence we estimate that about 200,000 snakebite events occur every year in the south-eastern part of Bangladesh alone. Considering future global climate change, our model projections show that snakebite incidence in Bangladesh might not significantly decrease in the future (- 2070-); however, the distribution of probabilities might change, with a predicted increase of snakebite incidence in the hilly areas of the country. Using climatic data to predict snakebite incidence in Bangladesh allowed us to provide estimations of the total annual number of snakebite cases in the study area. As in most countries, the scarcity of accurate epidemiological data in official records might have masked the real magnitude of this problem. Our analysis suggests that the problem of snakebite envenoming in Bangladesh might be worse than currently perceived. A long-term sustainable snakebite program plan should be designed and institutionalized, considering climatic, geographical and human demographic variables, to obtain better data and facilitate the implementation of accurate snakebite management programs for this country.

Comparison of bias correction methods to regional climate model simulations for climate change projection in Muger Subbasin, Upper Blue Nile Basin, Ethiopia

ABSTRACT The objective of this study was to evaluate the best performed bias correction methods to simulate the regional climate models for future climate change projections in Muger Subbasin. Delta change methods perform very good with a coefficient of correlation of 0.99 and a percent of bias –3. When we compare its corrected simulation result with observed data, delta change method seems to be with no biases for maximum temperature, but it increases by 1.67 °C from the mean for minimum temperature of 0.39 and 38.41 mm for monthly and annual precipitation, respectively. Delta change methods underestimate the model result for both temperature and precipitation. Linear scaling and variance scaling methods overestimate the maximum temperature of the simulation by 0.002 and 0.004 °C amount from the mean of the observed data, but it underestimates 1.59 and 1.56 °C the minimum temperature, respectively. The long-term temperature projection values (2060–2090) are higher than the near-term projections (2030–2060) for both RCP2.6 and RCP8.5 scenarios. Similarly, the change in annual precipitation for the long-term is higher than the near-term projections. As a conclusion, the results draw attention to the fact that bias-adjusted regional climate models data are crucial for the provision of local climate change impact studies in the Muger Subbasin.

Continuing benefits of the Montreal Protocol and protection of the stratospheric ozone layer for human health and the environment.

The protection of Earth's stratospheric ozone (O3) is an ongoing process under the auspices of the universally ratified Montreal Protocol and its Amendments and adjustments. A critical part of this process is the assessment of the environmental issues related to changes in O3. The United Nations Environment Programme's Environmental Effects Assessment Panel provides annual scientific evaluations of some of the key issues arising in the recent collective knowledge base. This current update includes a comprehensive assessment of the incidence rates of skin cancer, cataract and other skin and eye diseases observed worldwide; the effects of UV radiation on tropospheric oxidants, and air and water quality; trends in breakdown products of fluorinated chemicals and recent information of their toxicity; and recent technological innovations of building materials for greater resistance to UV radiation. These issues span a wide range of topics, including both harmful and beneficial effects of exposure to UV radiation, and complex interactions with climate change. While the Montreal Protocol has succeeded in preventing large reductions in stratospheric O3, future changes may occur due to a number of natural and anthropogenic factors. Thus, frequent assessments of potential environmental impacts are essential to ensure that policies remain based on the best available scientific knowledge.

Channel changes over the last 200 years: A meta data analysis on European rivers

AbstractThe combined analysis of past evolutionary trajectories of channel morphology and temporal patterns of driving factors is fundamental to understanding present river conditions, supporting river management and evaluating future changes. Rivers in Europe underwent important channel changes during the Anthropocene in response to changing natural drivers and anthropogenic pressures. A considerable number of papers have been published on this topic, in the last decades. In this study, a comprehensive meta‐analysis on channel changes during the last 200 years in Europe was performed, aiming to provide quantitative information on the intensity of changes, to highlight regional scale similarities and dissimilarities in evolutionary morphological trajectories and to discuss the main causes of such changes. Based on a review, 102 papers were selected, addressing 145 channel reaches flowing through five main mountain ranges (Iberians, Alps, Apennines, Balkans and Carpathians) in the southern and eastern parts of Europe. The results show that active channel narrowing (between 26% and 36% on average) and incision (between 1 and 2 m) prevailed in most rivers between the 1800s and the 1950s, although widening was documented in some rivers of the Alps and the Apennines. Most multi‐thread reaches maintained their pattern until the mid‐20th century. Active channel changes accelerated during the 1950s–1990s (or 2000s) period, with channel narrowing up to 60% and channel incision up to 14 m. Multi‐thread patterns strongly decreased in frequency, with anabranching channels disappearing and single‐thread patterns becoming predominant. The cumulative effect of multiple and concomitant human pressures (gravel mining, channelisation and damming) was identified as the main driving factor for these accelerated changes. These findings must feed the public debate about preventing alterations of river ecosystems—exerted by anthropic disturbances—in a context of rapid economic development, especially in river systems still poorly altered and thus preserving wide, active and heterogeneous fluvial corridors.

Climatology of severe hail potential in Europe based on a convection-permitting simulation

AbstractWe present a new approach to identify severe hailstorms in a convection-permitting climate model, and build a climatology of severe hail potential in Europe using an ingredients-based approach based on a 20-year long hindcast simulation. Severe hail in Europe occurs mostly in southern regions (up to 40 times a year per 10,000 km2 around Northern Italy), and from May to August. It peaks from afternoon to evening hours on land, whilst sea areas are prone to hail at any time of the day. The Mediterranean Sea experiences severe hailstorms mostly in autumn: the central Mediterranean has the highest frequency among all regions studied, and may be considered as an unknown alley for hailstorms in Europe. Results derived from the high-resolution model are in very good agreement with existing hail climatologies constructed from observations, including the fine scale spatial variation. We conclude that our approach provides a reliable proxy for studying future changes in severe hail in convection-permitting simulations.

Impacts of Future Changes in Heavy Precipitation and Extreme Drought on the Economy over South China and Indochina

Impacts of Future Changes in Heavy Precipitation and Extreme Drought on the Economy over South China and Indochina

A multi‐scenario analysis of climate impacts on plankton and fish stocks in northern seas

AbstractGlobally, impacts of climate change display an increasingly negative development of marine biomass, but there is large regional variability. In this analysis of future climate change on stock productivity proxies for the North Sea, the Norwegian Sea, and the Barents Sea, we have provided calculations of accumulated directional effects as a function of climate exposure and sensitivity attributes. Based on modelled changes in physical and biogeochemical variables from three scenarios and knowledge of 13 different stocks' habitats and response to climate variations, climate exposures have been weighted, and corresponding directions these have on the stocks have been decided. SSP1‐2.6 gives mostly a weak cooling in all regions with almost negligible impacts on all stocks. SSP2‐4.5 and SSP5‐8.5 both provide warmer conditions in the long term but are significantly different in the last 30 years of the century when the SSP5‐8.5 warming is much stronger. The results show that it is the current stocks of cod and Calanus finmarchicusin the North Sea, and polar cod and capelin in the Barents Sea that will be most negatively affected by strong warming. Stocks that can migrate north into the northern seas such as hake in the Norwegian Sea, or stocks that are near the middle of the preferred temperature range such as mackerel and herring in the Norwegian Sea and cod and Calanus finmarchicus in the Barents Sea, are the winners in a warmer climate. The highly different impacts between the three scenarios show that multiple scenario studies of this kind matter.

ЧИ ПОТРІБНЕ УКРАЇНІ СПЕЦИФІЧНЕ РЕГУЛЮВАННЯ ВИКОРИСТАННЯ ГЕНЕТИЧНОЇ ІНФОРМАЦІЇ ДЛЯ ОЦІНКИ РИЗИКІВ У СТРАХУВАННІ?

Introduction. The article examines the specifics and role of genetic information for insurance risk assessment in the life insurance market in Ukraine. Problem Statement. The insurance market developments of different countries are increasingly characterized by the adoption of specific regulations regarding the features and conditions of use of genetic information. Therefore, the issue of regulating the rights and obligations of all participants in insurance relations regarding the use of such information of future owners of insurance policies for underwriting in insurance requires a comprehensive solution taking into account the interests of all parties. The purpose of the research is to evaluate the necessity of application of specific regulations on the insurance market, specifically in the field of using genetic data for insurance purposes. Methods. The sources of materials were scientific publications, analytical studies, as well as legislation in the field of regulation of the use of genetic information for the assessment of insurance risks. The research paper used the following empirical methods, such as analysis, synthesis, grouping, description, comparison, theoretical generalization. Results. The results show that currently some risks exist in Ukraine: firstly, the genetic discrimination, since most life insurance companies are interested in the genetic information of policyholders, and can request it from any third parties: therefore, there is a possibility of using it to assess insurance risk; secondly, an information asymmetry, which is a consequence of greater awareness of insurance companies about the insurance risks than that of the policyholders. After all, policyholders may not inform the insurance company about all the genetic data (for example, the results of genetic studies) that describe their genetic predisposition to future changes in health. Conclusions. This study substantiated factors which confirm the relevance of introducing legislative regulation regarding the use of genetic information (including the results of genetic analyzes) for underwriting in insurance.

The role of household labour for sustainable intensification in smallholder systems: a case study in cocoa farming systems

Sustainable agricultural intensification aims at increasing yields on existing agricultural land without negative environmental impacts. Managing pests and diseases contributes to increasing yields. Without synthetic pesticides, this management is labour intensive. Smallholder farming systems heavily rely on manual and household labour, which will be affected by future demographic changes. Knowledge on how these changes will affect sustainable intensification is limited. Based on a case study of Ugandan cocoa farms, we tested the impact of increased household labour availability on pest and disease management (PDM) practices and pesticide use. We made use of a unique quasi-experimental design, in which household labour increased during the national COVID-19 lockdowns as children did not attend school and family members returned from cities. Our interview data from 2019 to 2021 showed that household labour availability increased on average by 0.8 (±2.5) household members and 16% of labour days per hectare. Using different regression models complemented with qualitative insights, we found that the uptake of alternative PDM practices significantly reduced pesticide quantities and expenditures. The implementation of alternative PDM practices was only weakly influenced by household labour availability and increased with farmer training and trust in alternative practices. These results imply that alternative PDM practices are an important pillar for production with little or without synthetic pesticides and their adoption requires support and incentives, especially on labour or resource-constrained farms.