Tuesday’s Soil Ecosystem Service – Climate regulation (“cooling effect”)
Outputs: Micro and macro-climate regulation
Definition: The soil ecosystem service local climate regulation refers to the micro-climate effects of soil and vegetation due to evapotranspiration.
Relevant effects, processes and controlling soil properties: The evapotranspiration (abbreviated as ‘ET’ that stands for evaporation from soil and transpiration from plants) reduces high air temperature. The higher the evapotranspiration, the more energy is used and the temperature is lowered.
The potential micro-climate regulation depends on both, the evaporation from the soil surface and the transpiration by plants. Quantitatively, the latter is more important in general, especially in the ecosystems with high bio-mass production, like forests or crops, depending on the type and the age of the forest, the type of crops, the evapotranspiration can be quite comparable in some cases.
With respect to soils, the water storage capacity is controlling both, the evaporation and transpiration, and is regulated for its part by pore volume and pore size distribution. These properties are generally controlled by active soil depths, stone content, soil structure, soil texture, density, and amount and type of organic matter.
Relations to the entire ecosystem: the ET contributes to the water cycle and therefore is important for the whole terrestrial ecosystem. Nonetheless, the soil acts as a reservoir for water enabling and limiting these processes due to its limited water holding capacity. In order to recharge the soil water content, precipitation needs to percolate in soil and fill the soil pores volume. The pores need to be appropriate size; not micro-pores and neither large pores. Only pores that are narrow enough and wide enough to retain water for release comprise the pore volume that are involved in the ET process.
Relations to other services: Micro-climate regulation is closely linked to the water storage soil ecosystem services as well as a number of others, such as the biomass production in agriculture and forestry.
Climate change impacts: In the course of climate change and rising temperatures, the cooling effect of soil will be more important especially in urban areas, that are in general sealed soils/surfaces and small vegetated areas, such as parks, lawns, etc.
Demand aspects: In the course of climate change soil water storage and thus the potential evapotranspiration and cooling effect will turn out to be more crucial for the society, i.e. human health, and of course also for other organisms and their habitats.
- Output: Buffering/adjusting (micro) climate
- Provision: The ET from the soil and vegetation leads to mitigate overheating and contribute to the cooling effect. The capacity of soils to deliver this service is closely linked to soil water storage capacity that depends on soil properties such as soil texture, structure, humus content, density/compaction and some others.
- Demand: With climate change, the cooling effect will gain importance in all but especially in urban ecosystems.
- Threat: Soil degrading processes such as soil sealing, compaction, and erosion, threatens the micro-climate regulation.