Thermal pollution is a process that changes the temperature of the environment in a detrimental way. This change in temperature can be reflected both upwards and downwards, negatively affecting the quality of air, water and living beings.


This type of pollution is less mentioned than others, but it is no less important, and many environmental organisations have already taken up the fight against thermal pollution.

Thermal pollution is caused by industrial activity, which introduces heat into the environment in an uncontrolled manner, for example:

  • The use of water as a cooling system: the main causes of this pollution are industrial and manufacturing plants. These plants obtain water from nearby sources to avoid overheating their machines, which they then discharge back to this source, but at a higher temperature. When this water is returned to its natural source, the temperature of that body of water increases significantly.
  • Deforestation and soil erosion: these factors increase the level or expose water bodies to sunlight, which causes them to heat up abnormally.
  • Natural causes: for example, volcanoes and geothermal activity can also have an impact on the warming of groundwater and oceanic waters, with major environmental impacts.

What are the consequences of thermal pollution?

  • Reduced oxygen levels in water: Warm water can retain lower amounts of dissolved oxygen than cold water, due to its excess internal energy. This makes the water less suitable for life, suffocating animal species.
  • Increased toxins: water from industries flowing into seas and rivers may contain toxins and these have an effect on the ecology of the area, causing more diseases to develop.
  • Mass migration: rising or falling temperatures can cause species to migrate to environments where conditions are more suitable, affecting organisms that depend on these species for their survival.

To act and fight against thermal pollution there are some solutions such as reinforcing ecological legislation, recycling water from industrial processes or implementing reforestation plans.

Learn more about renewable energies and the environment in our blog.