P9 Flashcards
Human degradation of the landscape and ecosystems
- Table 7.4 attempts to quantify the impact of activities such as walking on a range of commonly occurring ecosystems in glaciated environments.
- There seems to be a threshold beyond which the vegetation begins to suffer and the downward spiral of wear shown in Figure 7.12 sets in.
- Other types of tourism, such as pony trekking or mountain biking, are even more damaging than walking.
- Inevitably glaciated highland areas suffer from soil erosion, especially when slopes are exposed, for example by clear-cut tree felling or other examples of deforestation, as this exposes the fragile ecosystems to the weather.
- Soil erosion is a major problem in many Andean areas as the slopes are often over-cultivated or overgrazed, largely because of pressure on the land to provide subsistence for growing populations.
The effects of people walking on mountain ecosystems
The effects of wear on an ecosystem
Phenology:
The study of the timing of natural events and phenomena, such as the first day snowdrops appear, in relation to climate.
Glacial environments in peril
- A global snapshot of the state of the world’s glaciers (in 2015) clearly shows the impact of climate warming - with supporting climatological and phenological evidence (impact on various weather events, such as first snows, first pussy willow catkins out, first day of lawn mowing and so on).
- While some of the world’s glaciers are still advancing, the vast majority are currently retreating.
Here are some scary facts: - On the eastern slopes of the Rocky Mountains, all the glaciers have lost between 25 and 75 per cent of their mass since 1850.
- In 1949 in Tajikistan, Central Asia, glaciers covered 18,500 km2 of land; in 2012 the covered only 11,000 km2, a 38 per cent decrease.
- Around 95 per cent of Himalayan glaciers are in rapid retreat; for example, the Khumbu Glacier (one of the highest in the world at the base of Everest) has retreated over 5 km since 1953.
- Areas in Peru and Bolivia covered by glaciers shrank by 25 per cent over the last 30 years.
There are very few areas where glaciers are expanding. - One example is that of the maritime glaciers in Scandinavia; here the elements of changing precipitation have contributed to a more positive mass balance.
- Data from the satellite surveys of the Greenland Ice Sheet shows a huge decrease in the ice-covered area, and new data from West Antarctica shows it is beginning to follow trends in East Antarctica with a massive loss in shelf ice.
- Recent and regular surveys confirm that this melt and retreat is happening at an ever-increasing (exponential) rate as positive feedback is amplifying the process
less ice → loss of albedo → reduced reflection → more atmospheric warming → more melting - The destabilising effect of climate warming can be looked at in two very significant contexts - changes to the hydrological cycle and changes in sea level.
Changes to the hydrological cycle
This will have serious consequences for millions of people.
Mountainous areas and diminishing water supply
- In mountainous areas such as the Andes and Himalayas, glacial meltwater feeds rivers; changes in discharge will have knock-on effects on sediment yield and water quality.
- Rivers in Asia, such as the Mekong, Yangtze, Brahmaputra, Ganges and Hwange Ho, are all fed by Himalayan glacial meltwater.
- The loss of a steady supply has huge implications for the population powerhouses of India and China (together containing over a third of the world’s population), both emerging as superpowers with almost insatiable demands for water for development of both their people’s quality of life and their economies.
- Western China’s semi-desert area contains 350 million farmers dependent on water supplied from the glaciers of the Tibetan plateau, an area experiencing high amounts of glacial thinning.
- Water shortages could affect 538 million people - some 42 per cent of China’s people - hence the development of massive hard-engineering solutions for water security such as dams, and the South-North water transfer scheme.
- In India the reduction of glacial meltwater flowing into the Ganges-Brahmaputra system is likely to result in at least 500 million people facing water shortages, with nearly 40 per cent of India’s irrigated (post-Green Revolution) land being affected.
The High Andes p1
- Runoff from ‘glacierised’ basins is an important element of water budgets in the High Andes, assuring sufficient supplies of drinking water, HEP, ecosystem viability and integrity, as well as year-round flows for an increasingly intensive irrigation-based agriculture.
- Any changes induced by Andean glacier retreat will therefore have both economic and social consequences and will require adaptation measures.
- Andean ‘tropical glaciers’ have declined by around sixteen per cent overall since 1970, but many smaller glaciers have disappeared completely, for example Cotacachi in Ecuador or, almost disappeared (82 per cent gone) Chacaltaya in Bolivia.
- While the rapid melting initially led to an unsustainable net increase in hydrological run off, now there is the issue of loss of biodiversity and declines in agriculture and tourism, with many almost water-less streams.
- As glaciers cease to act as runoff regulators, seasonal water and HEP power supplies will be affected.
- Bolivian urban centres such as La Paz, El Alto (total population 2.5 million) rely on glacier meltwater for about 40 per cent of their drinking water supply.
- In Quito in Ecuador, the situation could be even worse, with glacial meltwater currently contributing 50 per cent of the water supply for its 2 million people.
- Changing hydrological conditions will affect water costs and the ability of the two urban areas to maintain vibrant economies.
The high Andes p2
- Various scenarios have been modelled for the discharges of the Andean streams with and without melting, and there is no doubt that additional streams will need diverting for both urban areas from a wider area, and soon.
- Glacier retreat will also affect HEP generation (50 per cent of total energy in Ecuador and 80 per cent in Peru comes from HEP).
- There are economic consequences of this reduction - including the extra costs of electricity as well as the possible need for rationing supply.
- There are cultural, almost spiritual, costs also for the Quechuan and Aymaran Indian people, who have long-revered the highest snow-covered Andean peaks as religious icons.
- Rapid glacier retreat will disrupt the water cycle in a whole series of individual glacier-dependent basins, thus having a local impact on agricultural communities, but at the same time there will be national impacts as countries have to change their energy mix for generating electricity.
- For example, Peru may have to invest in additional thermal-based power stations or gradually develop alternative energy sources, as well as building additional reservoirs for drinking water, all at higher costs to its economy even though its own population has contributed little to the causes of climate change.
There are a number of possible approaches to the management of cold environments,
Do nothing
Business as usual
Sustainable exploitation
Sustainable management
Comprehensive conservation
Total protection
Which strategy is appropriate depends on the area and the interplay of the views of involved players. In some areas there are immediate crises, for others time to plan ahead. For most areas there are a number of alternative strategies; often these are appropriate only for certain parts of a large area. Zoning is often a very useful middle way, with the highest-value wilderness areas fully protected, possibly surrounded by areas where sustainable activity is permitted - for example, the buffer zone within a biosphere reserve, and designated areas which are targeted for economic development.
Do nothing
lies at one end of the spectrum. It allows multiple economic uses to flourish. The ethos would be to allow cold environments to be exploited for whatever resources are in demand and profitable.
This approach might be supported by governments at local or national level for revenues, or by some local people, for example chambers of commerce or trade unions for employment potential, or by developers such as industrialists and globalised TNCs, for example energy and mining companies.
Business as usual
is a very similar approach, leaving the area as it currently stands, but this might include aspects of pre-existing sustainability such as self-regulation on environmental issues. All TNCs have pre-existing environmental policies as part of their mission statements. With the exception of conservationists, most players are content with the status quo.
Sustainable exploitation
- can be regarded as a middle way; it targets development for profit but with the insistence on mandatory environmental regulation, for instance waste disposal.
- It can be channelled to provide distinctive benefits for the community, for example the development of fishing for local communities or sustainable hunting.
- In theory it takes into account the vested interests of many players at a variety of scales, but it relies on considerable compromise for it to be successful.
Sustainable management
- attempts to develop an area in a way that uses resources for the benefit of the existing community without destroying the environment but, at the same time, conserving resources for future generations.
- The four facets of the sustainability quadrant or the three facets of the stool of sustainability are very difficult to achieve, especially in cold environments.
- There are tensional forces between the need to conserve fragile, vulnerable environments yet at the same time to exploit vital resources for the economic well-being of future generations.
- This is very clearly shown by the controversy over Alaskan oil where there is a clash between environmentalists, local indigenous peoples, state and national governments, and oil companies.
- Many NGOs, such as the World Wide Fund for Nature (WWF), favour sustainable development as an approach as ultimately it could be a good way to conserve the landscape and support indigenous communities.
Comprehensive conservation
- aims to protect and conserve glacial and periglacial environments as wilderness, especially where still in a pristine condition.
- Only carefully regulated ecotourism or organic eco-farming is likely to be favoured by environmentalists and those allowed to practice and enjoy it (local businesses and tourists).
- Exploitative activities such as mining would not be permitted.
- Governments might be ambivalent towards it as, in the short term, less income might be earned.
Total protection
is an approach really only favoured by conservationists and some traditionalists among local people, as this does not permit access to the pristine environment at all, except perhaps for scientific monitoring and research purposes. It therefore does not allow local people to earn revenue from it, or tourists to enjoy it.