Environmental Degradation

Sea-level change (sea-level rise / sea-level fall) refers to a change in the height of sea level, both globally and locally (relative sea-level change), at seasonal, annual, or longer time scales. It results from a change in ocean volume due to a change in the mass of water in the ocean (e.g. melting of glaciers and ice sheets), changes in ocean water density (e.g. expansion under warmer conditions), changes in the shape of ocean basins, changes in the Earth's gravitational and rotational fields, and local land subsidence or uplift (IPCC, 2019). 

Salt-affected soils consist of saline and sodic soils. Saline soils are those with an elevated amount of soluble salts, which reduces the ability of plants to take up water from soil due to the high osmotic pressure of the soil solution (FAO, 1985).

Eutrophication refers to the phenomenon of increased production of organic matter, primarily nitrogen and phosphorus, in aquatic systems (Nixon, 1995). Eutrophication can be caused by human activities (e.g. sewage outfall, agricultural runoff, aquaculture) and may result in secondary environmental effects such as algal blooms and fish kills (NOAA, 2007; UNEP, 2015). Given the complex structure and functioning of ecosystems, and the multitude of pressures they face (Cloern, 2001), the precise definition of eutrophication remains to be established (Pannard et al., 2024). 

Biodiversity loss refers to the reduction of any aspect of biological diversity (i.e. diversity at the genetic, species and ecosystem levels) in a particular area through death (including extinction), destruction or manual removal. It can occur at many scales, from global extinctions to local population extinctions, leading to a decline in total diversity at the same scale. 

Deforestation is the conversion of forest to other land use independently of whether human-induced or not (FAO, 2023). 

Forest declines and diebacks are episodic events characterised by premature, progressive loss of tree and stand vigour and health over a given period without obvious evidence of a single clearly identifiable causal factor such as physical disturbance or attack by primary disease or insect (Ciesla & Donaubauer, 1994).

Forest invasive species are any species that are non-native to a particular forest ecosystem and whose introduction and spread cause, or are likely to cause, socio-cultural, economic or environmental harm, or harm to human health (adapted from FAO, 2015). 

Forest disturbance is the damage caused by any factor (biotic or abiotic) that adversely affects the vigour and productivity of the forest, and which is not a direct result of human activities. It includes disturbance by insect pests, diseases, severe weather events and fires (FAO, 2018; 2020). 

Any unplanned and uncontrolled vegetation fire that, regardless of ignition source, may negatively affect social, economic or environmental values, and require suppression response or other action according to agency policy (FAO, 2024).

Desertification refers to land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities (UNCCD, 2017).