Moon Soul Graduate School of Future Strategy, KAIST

Abstract
By occupying over 80% of global human water footprint and getting involved over one-third  of  human caused land cover change for the last six decades, agriculture is one of the largest interferences of human activity on the Earth system. Meanwhile, demographic structure can be a proxy for human societal features, since it is both cause and result of the human socio-economic activity. However, from the land supply inventory point of view, current integrated assessment modeling or land use allocation modeling frameworks are not including societal factors. Hence, assessment on human socio-economical structure and resulting workforce in the context of agricultural land supply inventory would introduce new channel of human influence on the Earth system.
In this study, we proposed a linear model and a framework to project the future workforce available cropland area, based on assumptions of maintaining historic transition pathways of industrial structure and optimal workforce arrangement. The workforce available cropland area projection is based on the two components: the number of national agricultural employment, and land-labor productivity (cropland area per agricultural employment). The model and framework utilize data of GDP per capita, rural population share, workforce population, labor force population rate, unemployment rate, agricultural employment share, cropland area, agricultural total factor productivity.
For the assessment of human-side pressure on agricultural land supply inventory, comparison between future projected workforce available cropland and potentially available cropland was made. From the comparison, regions with 1) continuous increase of workforce available cropland area (USA, Australia), 2) various projected workforce available cropland area according to industrial structure with increasing potentially available cropland area from climate change (Canada, Russia), 3) various projected workforce available cropland area according to policy and industrial structure without potentially available cropland area change (Africa), 4) workforce available cropland saturated by decrease of potentially available cropland area (South Asia) were recognized. In the global scale point of view, 0.4 ~ 3 billion ha of increase in cropland supply inventory was projected, according to various SSP and RCP scenarios.
The result of this study can introduce human-societal modulation on agricultural land supply, therefore expected to enable more realistic future projection, and contribute to climate response policy development. Grid-based projection of future workforce available cropland would be developed via further studies, expected to enable more sophisticated and realistic estimation of crop production, agricultural carbon emission and water resource utilization.

Key Words: Agriculture; Land Use; Workforce; Demographic Change; SSP Scenario