Contrasting Centennial‐Scale Climate Variability in High Mountain Asia Revealed by a Tree‐Ring Oxygen Isotope Record From Lahaul‐Spiti

Abstract

Glacier response analyses in High Mountain Asia have revealed that the glaciers from the Karakoram region were in balance or thickening while most from the other regions were thinning, the “Karakoram anomaly.” It is, however, not clear whether this contrasting glacier response in High Mountain Asia is the result of regionally varying climate trends. Here, we give evidence for regionally varying climate trends by presenting a contrasting centennial-scale variations of oxygen isotope composition (δ18O) of juniper trees from the Indian Himalayan region (present study) and Karakoram. The persistence of contrasting δ18O trends in the two regions over the past millennium indicates that regionally contrasting climate trends are a natural phenomenon. Regionally distinct hydroclimatic trends revealed here can explain the anomalous glacier mass balance trends in the Karakoram region and hence the “Karakoram anomaly.”