Increasing Incidence of Droughts Since Later Part of Little Ice Age Over North-Western Himalaya, India

Droughts are recurring phenomena in the north-western Himalaya causing severe socioeconomic hardships. Our understanding on temporal and spatial occurrence of such extreme droughts in long-term perspective is constrained due to limited short-term weather records. Toward fulfilling such a large data void, we developed a network of ring-width chronologies of Himalayan cedar from seven moisture stressed high-elevation sites in Kishtwar, Jammu & Kashmir. Moisture responsive ring-width chronologies were used to develop the annual Standardized Precipitation Index (SPI from previous year June to current year May (SPI12-May)) extending back to 1613 CE. The SPI reconstruction revealed annual to decadal-scale variability in droughts, which strikingly were more frequent and of larger magnitude during 1760s-2017 CE in comparison to the earlier part of the reconstruction (1613-1750s CE). Our SPI12-May record revealed strong consistency with other tree-ring-based hydrological records from the western Himalaya. Spatial correlation analyses revealed strong linkage of the SPI with Tropical Pacific Ocean surface temperature.

Automated summary

Droughts in the north-western Himalaya cause severe socioeconomic hardships. Limited short-term weather records have hindered our understanding of the temporal and spatial occurrence of these extreme droughts in a long-term perspective. To overcome this data gap, we developed a network of ring-width chronologies of Himalayan cedar. By analyzing moisture responsive ring-width chronologies, we found that droughts during the period of 1760s-2017 CE were more frequent and of larger magnitude compared to the earlier part of the reconstruction. Our SPI12-May record showed strong consistency with other tree-ring-based hydrological records from the western Himalaya. Spatial correlation analyses revealed a strong linkage between the SPI and Tropical Pacific Ocean surface temperature.