Impacts of climate change and hydrological hazards on monsoon crop patterns in the Lesser Himalaya: A watershed based study

Abstract

The Lesser Himalaya region is a densely populated, nonglacial tract of the Himalaya. About 95 percent of the regional population depends on agriculture and forest resources but both have been declining rapidly in recent decades due to climate change and hydrological hazards. The main objective of this study was to assess the integrated impacts of climate change and hydrological hazards on monsoon crop patterns in the Lesser Himalaya through a geographic information system (GIS) database management system (DMS). The DMS comprises four GIS modules: climate informatics, land use informatics, hydro-informatics, and agro-informatics. The Dabka watershed in India’s Uttarakhand State is part of the Kosi Basin in the Lesser Himalaya in District Nainital and was chosen as a case study. The climate of the study area, depending on elevation, falls into three climatic zones: subtropical, temperate, and moist temperate, which are favorable for mixed forest, pine forest, and oak forest respectively. The results of the climate-informatics analysis suggest that in recent decades all these climatic zones have shifted towards higher altitudes and the areas of oak and pine forests have decreased. Forest degradation has accelerated hydrological hazards (high runoff, flash floods, river-line floods, soil erosion, and landslides) in monsoon periods, which affected about 22 percent of the cultivated land annually in 2005–2010. Monsoon crop yields decreased by an annual average of 1.40 percent between 1985 and 2010 while the population of the study area increased by an average of 2 percent each year in the same period. The negative correlation between annual crop yields and population growth has led to increased food security risks.