Climate Change in the Eastern Himalayas: Observed Trends and Model Projections
Abstract
The Eastern Himalayan region covers a broad spectrum of ecological zones in Eastern Nepal, Northeastern India, Bhutan, Tibetan Region and Yunnan of China and Northern Myanmar. The topography varies significantly over the area, and besides the atmospheric circulation, the climate in this region is influenced by a variety of physiographic features. The region is dominated by a monsoon climate from June to September and by westerly disturbances in the remaining months. Furthermore, the region is the source of many rivers which are the lifeline of downstream provinces and countries. The welfare of approximately 400 million people living downstream is inextricably linked with the natural resources of the Eastern Himalayas. Mountain biodiversity and wetlands are most likely to be affected by climate change. Glacial lake outburst floods, flash floods and landslides are becoming more frequent at the cost of lives, property, and natural resources and these are likely to be exacerbated by climate change. This paper deals with analyses of contemporary trends in key climatic variables. The Climate research Unit’s Time Series (CRU TS 2.0) data were used to analyze temperature and precipitation trends. Further, the study investigates likely future climate scenarios (2071-2100) for A2 and B2 SERS emission scenarios using the results of Region al Climate Model (RCM). The performance of RCM in simulating the climate over the Eastern Himalayas is also assessed. PRECIS (Providing Regional Climate for Impact studies) model simulated data were used for these analyses. The results of the analyses will be useful for impact assessment studies and for planning adaptation and mitigation measures. The analyses show that the major parts of the Eastern Himalayas are undergoing warming trends. Yunnan Province of China, part of the Kachin State of Myanmar, and the northeastern states of India and Assam show relatively less or no warming. However, eastern Nepal and eastern Tibet show relatively greater warming trends of more than 0.02°C per year. Such warming is found highest in winter and lowest in summer. Unlike temperature, precipitation does not demonstrate any consistent trends. Similarly, area-averaged B2 (A2) scenarios of PRECIS over Eastern Himalayas projected increases of 3.5°C (5.3°C), 2.8°C (3.8°C) and 2.9°C (4.3°C) respectively for winter, summer and annual mean temperatures by the 2080s. Likewise, B2 (A2) scenarios of PRECIS projected an increase of summer and annual precipitation by 17% (28%) and 13% (34%) of current precipitation, respectively by the 2080s.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.A33A0099D
- Keywords:
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- 0790 CRYOSPHERE / Weathering;
- 1605 GLOBAL CHANGE / Abrupt/rapid climate change;
- 1807 HYDROLOGY / Climate impacts;
- 5704 PLANETARY SCIENCES: FLUID PLANETS / Atmospheres