by Elana Manasse-Piha
Image by Climable
According to the U.S. Department of Energy, air conditioners use about 6% of all the electricity produced in the U.S., cost homeowners ~$29 billion annually, and release approximately 117 million metric tons of CO2 into the air every year! And this problem is growing.
The use of air conditioning causes a positive feedback loop: increased air conditioning use → increased electricity and refrigerant production → increased emissions of greenhouse gasses → increased global temperature → increased use of air conditioning. Meaning, the more we use air conditioning, the more we will need it in the future. The problems arise from the current methods and technologies we use for cooling.
In 2019, The Guardian reported that there were just over 1 billion single-room air conditioning units on earth, or 1 per every 7 people. By 2050, there will likely be more than 4.5 billion air conditioning units worldwide. Annually, the U.S. uses as much electricity for air conditioning as the U.K. does in total! If the rest of the world follows in the U.S.'s path, air conditioning will account for approximately 13% of global electricity use and produce 2 billion tonnes of CO2 a year.
Daikin workers assemble air conditioner units at the company’s plant in Shiga Prefecture.
Image: Daikin Industries Ltd. Source: Bloomberg.
Unfortunately, even if the electricity used to power air conditioning were obtained from carbon-neutral/renewable sources like geothermal or wind, modern air conditioning devices would still be a substantial emitter of greenhouse gasses due to their use of hydrofluorocarbons (HFCs) refrigerants. Refrigerants are fluids that absorb, transfer, and release heat into or out of an area and are used in refrigeration systems like air conditioning, heat pumps, and refrigerators. In an air conditioner, as a refrigerant is compressed and decompressed, it transitions between its liquid and gas phases, transporting and releasing heat from inside to the outside environment.
Basic refrigeration cycle. Source: Pete Hoffman.
HFCs were introduced after the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol) of 1987. The Montreal Protocol is an international treaty created to protect the ozone layer in the earth's atmosphere. Before the Montreal Protocol, the most common refrigerants used were hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons (CFCs). Unfortunately, HCFCs and CFCs degrade ozone which we need in our atmosphere to protect us from solar radiation. Although the Montreal Protocol is working by phasing-out HCFCs and CFCs, thereby helping to close the hole in the ozone layer, the chosen replacement refrigerants, HFCs, have their own issues.
Air conditioners on old building in backyard. Image taken by Darya Sannikova. Source: Pexels.
HFCs were selected as a replacement refrigerant because they do not degrade ozone. However, it was soon discovered that they are potent greenhouse gasses and are subsequently substantially contributing to another environmental disaster, climate change. In October of 2016, the Kigali Amendment was added to the Montreal Protocol to address this issue. It aims to gradually phase out HFC consumption by replacing it with inert or low reactivity alternatives. Project Drawdown calculates that using alternative refrigerants would reduce/sequester the equivalent of 43.53–50.53 gigatons of CO2 between 2020 and 2050!
While this is an expansive and intricate problem, there are solutions. Some solutions, like the Kigali Amendment, are already being implemented. Our next article addresses some of these solutions, including ones that individuals can take to cool their homes and businesses in an eco-friendly manner to break the positive feedback loop by relying less on electricity and refrigerants!
Banner image by Tom Fisk from Pexels