Sunday, June 14



Prof. Dr. Lochan Pd. Devkota
Central Department of Hydrology and Meteorology
Tribhuvan University


Change in local climate of Kathmandu has already been reported in national media. Scientific analysis of climatic indicators is important to confirm the public perceptions. This study attempts to fill the gap by analyzing the rainfall and temperature data of the Valley with a focus on winter season.

As a part of this study, temperature and rainfall data were analyzed. The key findings include increased number of hotter days and decreased number as well as volume of rainy days in winter months (December to February). Incidentally, this year's winter months (December 2008 through February 2009) remained total dry. Though there are rare incidents of this type of severe and longer drought in the history, this one is the second in three years. There is wide belief that such a frequent drought of this scale is the result of climate change. However, defining change in climatic pattern requires analysis of minimum of 30 years of data or more.

Annual temperature growth trend of Kathmandu is already established but the fact that the higher rate of temperature growth of winter season is rarely discussed. In this ground this study is significant in the ground that winter temperature growth in Kathmandu Airport station is statistically significant. Decreased amount of rains or absence of rains throughout winter has been noticed as a cause behind this sharp rise of winter temperature.

In Kathmandu Valley, the winter of 1998/99 was the hottest winter of 20th century with average of 12.26 °C. Normally, the central Valley receives about 33 mm of winter rainfall, while the southern slopes receive over 55 mm in winter. The high hill around the Valley received snowfall on 14th February 2007 first time after 62 years. This event has indicated that extreme events in weather are already experienced in Kathmandu as an effect of climate change.

With the increased frequency of extreme weather events, exposure of the Valley residents has increased significantly for two reasons. First, the alarming growth of Valley population is already coping with serious water shortage problem. The consecutive drought like conditions throughout winter has exacerbated the situation. Therefore the Valley is highly vulnerable to climate change. Unless there is an implementable plan of climate change adaptation, the future of the Valley will be very stressful through water management point of view. To this purpose, adoption of Integrated Water Resource Management (IWRM) is essential to address the challenge.

Key Words: Climate Change; Water Resources; Kathmandu; Temperature; Rainfall