Environment
Mountains feature a diverse range of ecological zones, and often they have higher endemic biodiversity than lowlands, including important genetic varieties of agricultural crops and animals. Mountain systems host 25 of the world’s 34 biodiversity hotspots. They also have an equally diverse range of human cultures. In mountain ecosystems, forests cover approximately 40% of the global mountain area, and the soils differ significantly from lowland soils, as they are shallower and more vulnerable to erosion. Such soils are easily and often degraded by various human activities, especially due to the removal of vegetation that exposes the bare soil.
Ecosystem degradation
Deforestation, intensive agriculture, pollution and construction of infrastructure in mountain areas can cause irreversible losses of biodiversity and ecosystems services. As of 2020, 57% of the global mountain area was under intense pressure, with ecosystem degradation concentrated at lower mountain elevations, where most human activities occur.
Under two climate change projection scenarios, the near-surface permafrost area will decrease by up to 66% and up to 99% by 2100.
As mountains warm and the cryosphere retreats, species and ecological communities tend to shift to higher elevations, resulting in an overall greening of higher mountain elevations.
The paramos are distributed along the Neotropical Andean mountain range in Colombia, Ecuador, northern Peru and the Bolivarian Republic of Venezuela. They make up one of the most biodiverse high-elevation ecosystems, and are critical for the survival of millions of people – providing the main source of clean water for inhabitants of capital cities such as Bogotá and Quito. Vegetation plays a major role in regulating the amount and quality of water supplied by these Andean ‘water sponges’. In addition to aiding infiltration of water to the ground, plant cover also reduces evaporation compared with bare ground. Plants can also capture water from fog.
The paramos have also provided a source of medicinal plants, grazing and agricultural land for Indigenous Peoples. However, the landscapes are changing, and their functionality is being reduced.
Mountain cryospheres and highland ecosystems provide essential ecosystem services to people living in mountains, and to billions in connected lowland areas.
Water regulation (including water storage and flood regulation) is one of the most important services – for example, an estimated two-thirds of irrigated agriculture globally depends on runoff contributions from mountains.
Other key ecosystem services include reducing the risk of erosion and landslides, cooling local temperatures, carbon sequestration, providing food and fibres, and maintaining pools of genetic resources for locally adapted crops and livestock.
Did you know?
During the snow-melt season in the spring and summer months, red snowfields – known as ‘glacier blood’ or ‘watermelon snow’ – have been found ubiquitously across the world and are caused by blooms of red algae. These areas decrease surface albedo and enhance solar energy absorption, accelerating ice- and snow-melt. Snow algae can be the main albedo reducers on wet snowpacks, and glacier ice algae can become the dominant albedo reducer.
At the ecosystem level, most of the options for addressing the impacts of changes in the cryosphere and high mountains involve conserving or restoring ecosystem functionality through nature-based solutions (NbS) or ecosystem- based adaptation: managing water using ‘grey green’ approaches, including restoring riparian zones, would reduce flooding and help maintain water quality.
Also, achieving land degradation neutrality is an overarching globally agreed goal that is particularly relevant to mountain areas in view of their vulnerability.
In the mountainous and vulnerable area of Torrent Catchment in the Pamir Mountains of Afghanistan, a blend of small-scale physical interventions and agroforestry or forest restoration has been used to protect local communities from landslides, avalanches and other hazards. This has also increased water security and improved livelihoods in the area. Local communities led and implemented the interventions. Local tree species planted included fruit and nut trees that are tended by, and benefit the livelihoods of, local women.
Full chapter
Consult chapter 6: Environment
