IndiGo airlines canceled its flights to Leh on Monday due to unusually high temperatures, which resulted in runway restrictions at the region’s airport. The mountainous area has experienced a significant increase in temperatures, a phenomenon attributed to the ongoing impacts of climate change on India’s cold desert regions.
In a statement, an IndiGo spokesperson explained, “IndiGo flight operations to and from Leh have been impacted due to the prevailing high outside air temperature in Leh, which is beyond the airline’s control.” For a Boeing 737, the maximum operational temperature at Leh’s Kushok Bakula Rimpochee Airport is 32 degrees Celsius. This airport is situated at an altitude of 10,682 feet above sea level, presenting unique challenges for flight operations.
Leh Airfield is known for having one of the most challenging approaches for pilots in India. Aircraft flying to and from Leh are specially equipped for high-altitude operations. However, high temperatures at these altitudes can severely affect flight operations due to aerodynamics, aircraft performance, and safety concerns. High temperatures reduce air density, which impacts lift, engine thrust, and the length of the runway needed for takeoff and landing.
At higher altitudes, air is less dense due to lower atmospheric pressure. Increased temperatures further decrease air density, affecting flight operations. Aircraft generate lift proportional to air density, so lower density means less lift at the same speed, necessitating a longer runway for takeoff. Jet engines rely on air intake for thrust, and lower air density reduces engine efficiency, especially critical during takeoff. A senior pilot with IndiGo explained, “Due to reduced air density at high temperatures, aircraft need higher ground speed to produce the same lift, requiring longer runways.”
Many high-altitude airports, including Leh, have limited runway lengths. Leh’s single runway stretches 2,754 meters, making it unsafe for aircraft to take off when temperatures rise. To mitigate these conditions, airlines may reduce passenger, cargo, or fuel loads, but this is not always sufficient, leading to potential flight cancellations.
After takeoff, the aircraft must climb to clear obstacles and comply with air traffic control. Reduced engine performance and lift in high temperatures compromise climb performance. Similarly, landing distances increase with higher temperatures due to reduced braking efficiency and deceleration capabilities.
The current high temperatures in Leh and Ladakh are partly due to a heat wave affecting northern India, particularly Jammu and Kashmir and Ladakh. However, Ladakh has been experiencing a general increase in temperature over the years. A study by Jawaharlal Nehru University scientists shows that the average temperature in Ladakh has risen over the last 30 years. Additionally, a 2023 study by the Wadia Institute of Himalayan Geology, published by Cambridge University Press, reported a significant decrease in the size of glaciers in Ladakh. The IPCC reports also highlight that the average temperature increase in the Himalayan region, including Ladakh, is higher than the global average rise.
Scientists have repeatedly warned that Ladakh’s rising temperature and precipitation will have devastating effects. Padma Rigzin, a climate and wildlife researcher at Shiv Nadar University, stated, “Generally, Ladakh is experiencing more warm days, increased rainfall, and flooding. This will impact glaciers, water systems, road systems, ecology, vegetation, wildlife, hydrology, cryosphere, transportation, and irrigation.”
High vehicular emissions, both from private and military vehicles, contribute significantly to the environmental changes in Ladakh. The presence of military vehicles is necessitated by geopolitical tensions, particularly with China. These emissions accelerate global warming, further melting glaciers that have historically fed the region’s rivers. The Stok Glacier has seen significant melting, while the Leh Glacier has completely disappeared, altering the ecosystem of this cold desert.
The combination of these environmental changes and the specific aeronautical challenges at high altitudes has led to disruptions in flight operations, highlighting the far-reaching impacts of climate change on aviation and regional stability.
