Global reductions in manual agricultural work capacity due to climate change.

Manual outdoor work is essential in many agricultural systems. Climate change will make such work more stressful in many regions due to heat exposure. The physical work capacity metric (PWC) is a physiologically based approach that estimates an individual's work capacity relative to an environment without any heat stress. We computed PWC under recent past and potential future climate conditions. Daily values were computed from five earth system models for three emission scenarios (SSP1-2.6, SSP3-7.0, and SSP5-8.5) and three time periods: 1991-2010 (recent past), 2041-2060 (mid-century) and 2081-2100 (end-century). Average daily PWC values were aggregated for the entire year, the growing season, and the warmest 90-day period of the year. Under recent past climate conditions, the growing season PWC was below 0.86 (86% of full work capacity) on half the current global cropland. With end-century/SSP5-8.5 thermal conditions this value was reduced to 0.7, with most affected crop-growing regions in Southeast and South Asia, West and Central Africa, and northern South America. Average growing season PWC could falls below 0.4 in some important food production regions such as the Indo-Gangetic plains in Pakistan and India. End-century PWC reductions were substantially greater than mid-century reductions. This paper assesses two potential adaptions-reducing direct solar radiation impacts with shade or working at night and reducing the need for hard physical labor with increased mechanization. Removing the effect of direct solar radiation impacts improved PWC values by 0.05 to 0.10 in the hottest periods and regions. Adding mechanization to increase horsepower (HP) per hectare to levels similar to those in some higher income countries would require a 22% increase in global HP availability with Sub-Saharan Africa needing the most. There may be scope for shifting to less labor-intensive crops or those with labor peaks in cooler periods or shift work to early morning.

Associação entre Espondiloartrose lombar e trabalho pesado / Association between lumbar spondiloarthrosis and heavy physical work

Objetivo: Estudar uma possível associação entre espondiloartrose lombar etrabalho pesado. Metodologia: Estudo epidemiológico transversal realizado no período de outubro/04 a outubro/05, baseado em casos atendidos por um hospital público de São Luís, MA, Brasil. Trabalhadores (1256) encaminhados ao serviço de ortopedia foram submetidos à História Ocupacional, Exame Físico Ortopédico e Radiografia de Coluna Lombar e Lombossacra em AP/P e Oblíqüa.Critérios de inclusão e exclusão selecionaram 456 trabalhadores de ambos os gêneros, na faixa etária de 28 a 48 anos. Estes foram agrupados, conforme sua ocupação, em trabalho pesado e não pesado e submetidos aos critérios diagnósticos de espondiloartrose lombar. Resultados: A associação entre trabalho pesado e espondiloartrose lombar foi realizada através do cálculo da razão de prevalências, cujo resultado mostrou-se elevado, evidenciando uma possível associação. A interferência de outras variáveis como possível viés de confundimento,tais como idade, gênero e peso corporal (IMC), foram controladas na fase de análise de dados através do teste de Mantel-Haenzel. O resultadofinal mostrou que não houve interferência dessas variáveis. Conclusões: Este estudo indicou uma possível associação entre exposição a trabalho pesado e espondiloartrose lombar.

Objective: To study a possible association between lumbar spondiloarthrosis and heavy physical work. Method: Epidemiological transversal study was performed from October/04 to October/05 based on some cases cared for at a public hospital in São Luís, Maranhão, Brazil. Workers (1256) sent to the hospital orthopaedic service were submitted to occupational history, physical orthopedic exam and vertebral lumbar and lumbossacral radiographs in AP/P and oblique view. A total of 456 male and female workers between 28 and 48 years of age were selected according to evaluation inclusion / exclusion criteria.They were categorized according to their heavy and non-heavy work and were submitted to the diagnostic criteria of lumbar spondiloartrhosis. Results: The association between heavy work and lumbar spondiloarthrosis was calculated using the prevalence ratio, which was high, evidencing a possible association.The interference of other variables as possible confounding factors, such as sex, age and body weight (BMI) were controlled in the data analysed using the Mantel-Haenzel test. The final result showed no interference of the mentioned variables. Conclusions: this study showed a possible association between heavy work exposure and lumbar spondiloarthrosis.