Human impacts on the Himalaya are increasing

Rapidly retreating Ponkar Glacier, extensive moraine instead of glacial ice

Rapidly retreating Ponkar Glacier, Nepal


We tend to think of the Himalaya as a place where we humans have little impact. As the earth’s tallest mountain range much of the area is unsuited to human occupation.  Even visitation is restricted by severe climate and steep terrain.  Pacific Eco-Logic directors recently returned from spending three months exploring parts of western and central Himalaya (in addition to two months a few years ago).  In this post we share a few thoughts about human impacts on the Himalaya.

The Himalaya is the high mountain country extending from Pakistan to south-west China. It includes parts of northern Pakistan and India, northern Nepal, Bhutan and parts of southwest China.  The Himalaya was formed as the Indian subcontinent, which had separated from the former great southern continent of Gondwanaland, collided into and under the supercontinent of Eurasia.

The early human users of the Himalaya were seasonal grazers who apparently reduced the extent of upland forest and modified subalpine and alpine vegetation. In central and eastern Nepal Tibetan refugees settled in upper forest and subalpine environments, developing the Sherpa culture and practices which are still closely linked to traditional Tibetan Buddhist customs.  There was land clearance for cultivation and grazing impacts similar to those associated with the earlier seasonal grazers.  At lower elevations humans arrived from the south.  Settlement was more dense and the impacts of land clearance and grazing more intense.  Border dyke irrigation based on summer glacial melt-water allowed crops suited to high altitudes to be grown in some settlements during warmer summer months.

The most widespread recent human impact on the Himalaya is that of climate change. Upper elevations are warming more quickly. There has been extensive glacial retreat.  Many areas that were dominated by glacial ice twenty years ago are now dominated by extensive tracts of glacial moraine.  In addition, previously relatively stable climate patterns are changing.  For example, areas that were consistently dry during the summer monsoon are now receiving more summer rain.  Rivers that once froze in winter are not freezing to the same extent.  The winter walking access along these rivers (such as the Zanskar) is at risk and may not be available for much longer.

Logging of native trees for their timber is damaging a number of forest areas, including those in National Parks and other protected areas. Some of this timber is used for constructing new accommodation for tourists as well as the rapidly increasing local populations.  In places this has been complicated by the 2015 Nepal earthquake which in some locations has been followed by an extensive rebuilding programme.  Timber has also been exported although there are now some controls.

Trees are also used extensively as firewood for cooking and heating. At higher elevations this is problematic and high altitude juniper forests have been extensively reduced in extent.  Paper birch, another high altitude forest type favoured for firewood, has also reduced in extent.  While there is a move to use LPG as the cooking fuel in lodges on trekking routes, firewood is still widely used in the tourist sector and by locals.  The heating of water for showers for use by tourists also encourages the use of more timber.  Again there is a move to use more LPG for this but cost is an issue.  LPG cylinders typically have to be carried on mules or zoes (yak-cattle cross-breeds) long distances to and from filling stations.

Although many locals are vegetarian, the grazing of livestock is widespread. This includes sheep, goats, cattle, yaks and zoes.  Nomadic herders can have relatively large flocks that significantly impact alpine, subalpine, forest and grassland habitats.  Some herders extend grazing areas by clearing/ cutting forest vegetation and set fire to forest and shrubland areas.  These herders can leave large amounts of rubbish around their seasonal “settlements”.  It is likely that the new cash economy and increased population has increased grazing pressures in many areas.

Another major impact is the on-going construction of roads. While popular with some local people, road construction in steep country can lead to on-going instability, erosion and significant damage to waterways.  Material is pushed, or slides, into streams and rivers.  Often it is difficult to keep such roads open in the winter and monsoon seasons, so they may only be able to be used occasionally.  The on-going push to construct roads further into steep or geologically unstable country threatens the integrity of many gorge and riparian habitats.

There has also been considerable large-scale hydro-electric power development, especially in India. This is typically associated with river diversions and more roads.  The reservoirs can flood large areas of riparian and gorge habitat.  In Nepal much of the Himalayan-produced hydro power is produced by local micro schemes supplying the local villages.

In mid altitude areas expanding populations have led to more forest clearance and the loss of former “meadows”. In such areas the areas under cultivation have expanded and there is new settlement with many new buildings.

A smaller scale impact is rubbish- especially plastic waste. The most developed programme to reduce the impact of plastic and other waste is in Sagarmatha National Park.  Here there are recycling collection points along the main trails and a waste disposal facility (incinerator) at Lukla.  Even so some people still dump rubbish off the side of some tracks and near settlements.  Most other Himalaya locations have no rubbish collection or recycling facilities.

Rubbish is not directly related to the amount of tourist visitation. In some parts of Nepal there are large amounts of widely distributed rubbish in locations where few tourists visit.  Plastic rubbish can be associated with nomadic herders and tea shops along trading routes.  Instant noodles are clearly very popular as are biscuits and sweets.  Plastic sacks, plastic footwear, tarpaulins, clothing and plastic packaging are also widespread.  Plastic drink bottles tend to be more associated with international tourists and can be present in large amounts.  Few settlements seem to have organised any form of removal.

Tourism can be a relatively good economic development option for Himalayan communities provided the environment is not damaged to provide facilities. Tourists can, however, lead to large volumes of helicopter traffic in locations such as Sagarmatha National Park, with the resultant noise pollution in otherwise remote wilderness.

Human impacts on the Himalaya are increasing and many are probably irreversible. In the rush to development there are risks that some fragile ecosystems will be irreversibly damaged.  Being part of the world’s highest mountain range does not provide the safety buffer it once did.