Heat pollution
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Heat pollution (atmospheric) should be distinguished from thermal pollution in water. Heat pollution is a key contributor to global warming and climate change. Global warming and the climate changes it produces are the result of heat trapped by greenhouse gases (CO2 emissions).
All the energy people use at home in the United States counts for a fifth of the heat in global warming , from industrial processes to household activities and urban lifestyles in general including all forms of transportation, and of course any use of energy irrespective of its source which deposits waste heat in the environment. All of this waste heat emitted into the atmosphere will contribute to global warming.
A considerable effort is being put into reducing fossil-fuel greenhouse gases by developing renewable energy sources and reducing carbon concentrations in the atmosphere. However, current levels of the heat-trapping gases in the atmosphere, and their longevity, suggest that it is also essential to reduce the amount of heat pollution emitted into the atmosphere.
The urban heat island phenomenon traps heat in thermal mass like concrete and black roads which absorb, store and then re-emit this heat to the urban air at night. This hot city phenomenon has far-reaching environmental sustainability and human livability implications, ranging from the aggravation of health problems such as heat stress, increasing the intensity of urban air pollution, and contributing to extreme weather events—in addition to the ever-increasing use of air-conditioners, with flow-on impacts for energy supply, brownouts and greenhouse gas emissions. Because most people on earth live in cities, and each city is also substantially hotter than its natural surroundings, urban contributions to global warming are significant.
The global climate is rapidly deteriorating—ice shelves are melting, sea-levels rising, and the Gulf Stream conveyor belt threatened while waves of hurricanes brew over hot oceans, and devastating weather extremes of all natures are more and more prevalent in every corner of the globe. Unless the amount of heat pollution emitted into the atmosphere is reduced, it will continue to silently and invisibly contribute to extreme climate change. Capturing and sequestering heat must become a part of the strategy to ameliorate urban and global climates.
[edit] Growth of human-made heat pollution
The emission of man-made heat is growing exponentially both feeding industrial growth and also as a consequence of it. In the 1970s it was calculated by Robert Ayres and Allen Kneese that if the then present rate of growth of man-made heat pollution continued for 250 years then emissions would reach 100% of the absorbed solar flux. This was calculated to result in an increase of the earth's temperature by 50 degrees C. A condition totally unsuitable for human habitation. However, noticeable perturbations are anticipated by climatologists when global man-made heat emissions (alone) reach only 1 percent of the solar flux.
The amount of heat pollution (in watts) each household produces is within a constant factor of the average net amount of electricity it uses (in watts); this is because energy usually ends up being converted into heat (e.g. any type of lightbulb, which converts energy into light, which then turns into heat when the light hits something). Other sources of heat include natural gas and any fossil fuels (for which country-wide yearly consumption statistics are commonly available), which contribute heat in exactly a constant factor, as well as body heat, where about 50% of consumed food energy is wasted as heat (the other half being used for body processes or left in the feces).
