Climate change impact on crop stress and food security in a semi-arid river basin

Abstract

This investigation explores the spatio-temporal variations of aridity across the Sabarmati River basin (SRB), India, using rainfall and temperature datasets for the baseline (1951–2019) and future (2020–2100) periods. The projected changes are analysed using a multi-model ensemble of five general circulation models under two representative concentration pathways (RCPs). The long-term variation and dependency between the aridity index (AI) and other climate indices are explored. Further, the sensitivity of Kharif and Rabi crops to atmospheric warming is investigated using anthesis heat stress (AHS) at the district level. The results project increased rainfall and temperature at the end of the 21st century. The projected rise in AI denotes a transition from semi-arid to sub-humid conditions in parts of the SRB, particularly the southern SRB. However, AI shows a stronger positive association with rainfall compared to temperature, which drives the basin towards moisture-sufficient conditions. High to very high AHS levels are noted for the Kharif and Rabi crops in all the districts. The escalating severe temperature episodes during RCP8.5 may significantly impact crop stress and food security in the SRB. Thus, there is a need to adopt resilient agricultural practices to overcome the negative impact of increasing temperatures in the future. HIGHLIGHTS Baseline and projected changes in aridity and its dependency on climate indices are evaluated.; Anthesis heat stress is calculated for Kharif and Rabi crops at the district level.; Transition of SRB towards moisture-sufficient conditions is noted.; Higher heat stress levels would cause food security issues, especially in RCP8.5 scenario.; Need to adopt resilient agricultural practices.;

Keywords

• anthesis heat stress
• aridity index
• climate change
• cmip5
• multi-model ensemble approach
• semi-arid basin