Integrated assessment of climate change and land use impacts on multicrop vulnerability in Mun River Basin, northeast Thailand

Abstract

Importance of the work: The quantification of climate and land use change effects on
multi-crop systems can inform strategic agricultural adaptation.
Objectives: To evaluate the combined effects of climate (CMIP5/CMIP6) and land use
change (LUC) on multi-crop economic output and to determine spatial susceptibility
across the Mun River Basin, northeast Thailand.
Materials and Methods: The decision support system for agrotechnology transfer
(DSSAT) model and the land-similarity-unit technique were applied to assess four major
cash crops: rice, maize, cassava and sugarcane. Land use was projected using a cellular
automata-Markov chain model. Economic effects were quantified across four scenarios:
baseline, climate change (CC)-only, LUC-only and integrated CC & LUC.
Results: The CC-only scenario caused an 8.9% reduction in total output. Rice and maize
had very unstable yields (coefficient of variance up to 43.0%). The LUC-only scenario
increased output by 4.5%, driven by converting rice paddies to higher-value crops.
The integrated effect resulted in a net reduction of 4.4%. District-level analysis revealed
non-uniform responses: uplands experienced output increases (+22.2% in Sangkha),
reflecting successful adaptation, whereas lowlands showed aggravated losses (-15.0%
in Kaset Wisai).
Main finding: Strategic land use adaptation can offset economic losses from climate
change. Spatial targeting is critical and vulnerability remains high in rainfed lowlands
where crop conversion is unsuitable.