Citation: Attaullah, H.; Khan, A.; Khan, M.; Khan, F.; Ali, S.; Masud, T.; Iqbal, M.S. The Karakoram Anomaly: Validation through Remote Sensing Data, Prospects and Implications. Water 2022, 14, 3157. https:// doi.org/10.3390/w14193157 Academic Editor: Letizia Lusito Received: 12 August 2022 Accepted: 29 September 2022 Published: 7 October 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). water Article The Karakoram Anomaly: Validation through Remote Sensing Data, Prospects and Implications Haleema Attaullah 1 , Asif Khan 2, *, Mujahid Khan 1 , Firdos Khan 3 , Shaukat Ali 4 , Tabinda Masud 1 and Muhammad Shahid Iqbal 5 1 Department of Civil Engineering, University of Engineering and Technology, Peshawar 25000, Pakistan 2 Department of Civil Engineering, Jalozai Campus, University of Engineering and Technology, Peshawar 25000, Pakistan 3 School of Natural Sciences (SNS), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan 4 Global Change Impact Studies Centre (GCISC), Ministry of Climate Change, Islamabad 44000, Pakistan 5 International Water Management Institute (IWMI), Lahore 54782, Pakistan * Correspondence: asifkhan@uetpeshawar.edu.pk or engrasif_civil@yahoo.com Abstract: Millions of people rely on river water originating from snow- and ice-melt from basins in the Hindukush-Karakoram-Himalayas (HKH). One such basin is the Upper Indus Basin (UIB), where the snow- and ice-melt contribution can be more than 80%. Being the origin of some of the world’s largest alpine glaciers, this basin could be highly susceptible to global warming and climate change. Field observations and geodetic measurements suggest that in the Karakoram Mountains, glaciers are either stable or have expanded since 1990, in sharp contrast to glacier retreats that are prevalently observed in the Himalayas and adjoining high-altitude terrains of Central Asia. Decreased summer temperature and discharge in the rivers originating from this region are cited as supporting evidence for this somewhat anomalous phenomenon. This study used remote sensing data during the summer months (July–September) for the period 2000 to 2017. Equilibrium line altitudes (ELAs) for July, August and September have been estimated. ELA trends for July and September were found statistically insignificant. The August ELA declined by 128 m during 2000–2017 at a rate of 7.1 m/year, testifying to the Karakoram Anomaly concomitant with stable to mass gaining glaciers in the Hunza Basin (western Karakoram). Stable glaciers may store fresh water for longer and provide sustainable river water flows in the near to far future. However, these glaciers are also causing low flows of the river during summer months. The Tarbela reservoir reached three times its lowest storage level during June 2019, and it was argued this was due to the low melt of glaciers in the Karakoram region. Therefore, using remote sensing data to monitor the glaciers’ health concomitant with sustainable water resources development and management in the HKH region is urgently needed. Keywords: the HKH region; equilibriumline altitudes; glaciers retreat; climate change; Hunza Basin; the Karakoram anomaly; remote sensing datasets 1. Introduction The study of the changes in the complex alpine glacier system (e.g., glaciers in the Hindukush, Karakoram, and Himalaya) is crucial for water resources development and management. Monitoring alpine glaciers imparts vast information about the response of glaciers to climate change together with the future prospects and implications for prosperity. According to the available studies, the rise in the global average surface temperature has caused glaciers to retreat and shift towards lower altitudes. Thus, glaciers are considered as a key and warning symbol of the escalating temperature due to changes in the climate [1,2]. The Indus River Basin (IRB) is one of the major basins of a giant and complex mountain- ous range of the HKH where more than 80% of the stream flow is generated by snow-glacier melts [3]. Various studies affirmed IRB as the most vulnerable and threatened region with Water 2022, 14, 3157. https://doi.org/10.3390/w14193157 https://www.mdpi.com/journal/water