In a broader sense, and with the concern about global warming, engineers do nothing to mitigate the effects on earth because they take air or cool water from the environment to exchange heat with their waste streams.

Almost half of all water withdrawn in the United States each year is for cooling electric power

plants. The cheapest and easiest method is to withdraw water from a nearby body of surface water, pass it through the plant and return the heated water to the same body of water.

Warmer temperatures lower dissolved oxygen content by decreasing the solubility of oxygen in water. Warmer water also causes aquatic organisms to increase their respiration rates and consume oxygen faster, and it increases their susceptibility to disease, parasites, and toxic chemicals. Discharge of heated water into shallow water near the shore of a lake also may disrupt spawning and kill young fish.

Fish and other organisms adapted to a particular temperature range can also be killed from thermal shock

While some scientists call the addition of excess heat to aquatic systems thermal pollution, others talk about using heated water for beneficial purposes, calling it thermal enrichment. They point out that heated water results in longer commercial fishing seasons and reduction of winter ice cover in cold areas.