environmental degradation
Change in the fraction of ISA (impenetrable surface area) in percent from 2001 to 2011. [74]
Habitat destruction and fragmentation are the primary proximate threats to species and the foremost cause of extinction. [65] [66]
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Environmental destruction can be broken into a few general categories and subsets: [66] [67]
Agricultural Expansion
1. permanent cultivation
- subsistence agriculture
- commercial agriculture
2. cattle ranching
3. shifting cultivation
- swidden agriculture (slash and burn)
4. colonization
- transmigration
- resettlement
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Infrastructure Expansion
1. transport extension
- roads
2. settlement/market extension
3. water development
- dams and impoundments
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Resource Extraction
1. logging
- commercial (for trade)
- fuel wood (domestic use)
2. mining, oil and gas, geothermal
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Other
1. military activities
2. outdoor recreation
- off-road vehicles
3. pollutants
4. disruption of fire ecology
Maps of planned economic corridors and concession areas overlaying forest in three tropical forest regions. [78]
As of 2020 the world is not on track to meet global deforestation targets. [77] [78]
The Amazon is expected to reach a tipping point of transgression from a rainforest biome to a tropical savanna biome by 2064, with dire consequences for rainfall throughout South America and global carbon sequestration. [220]
Soil erosion represents the greatest threat to soil fertility and productivity because it removes soil nutrients and substrate, eventually leaving arable land unproductive. [79] [80]
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"Soil erosion or simulation of topsoil loss has been severally reported to adversely influence such soil physical properties as root zone depth, gravel content, particle size distribution, strength, bulk density, porosity, aggregate stability, moisture retention capacity, moisture characteristics, saturated hydraulic conductivities, and infiltration rates in SSA (sub-Saharan Africa)." [81]
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Soil compaction, especially as a result of mechanized agriculture, has been shown to cause yield reductions of 25 to 50% in Europe and North America, and as much as 90% in West Africa. [82]
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Nutrient loss is especially a problem in sub-Saharan Africa, and salinization of the root zone in semi-arid areas affects 33% of the potentially arable land area of the world. [82]
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The state of global soil degradation (UNEP, 1997). [85]
Desertification in sub-Saharan Africa is advancing at a rate of 5 km a year. [83]
Desertification vulnerability based on soil and soil climate data. [84]