Air conditioning paradox

The air conditioning paradox arises from the usage of air conditioners to adapt to the effects of climate change, leading to higher energy consumption and heat generation as a byproduct, thereby exacerbating the problem.^[1][2][3][4]

An air conditioner

The paradox is particularly concerning in emerging economies. While air conditioning has become a symbol of modernity and comfort, its widespread adoption could significantly increase global carbon emissions, undermining efforts to limit global warming. Alternatives are currently being explored by governments and researchers, such as more energy-efficient systems, passive cooling techniques, and the development of low-GWP refrigerants. However, balancing the demand for cooling with the need to reduce carbon footprints remains a complex and pressing issue.^[5][3][2]

History

Invention of the air conditioner

Main article: Air conditioning § First devices

Willis Carrier, who is credited with building the first modern electrical air conditioning unit

In 1901, American inventor Willis H. Carrier built what is considered the first modern electrical air conditioning unit.^[6][7][8][9] In 1902, he installed his first air-conditioning system,^[10] patented "air conditioning" in 1906,^[11] and by 1914, the first domestic air conditioning was installed.^[12] Innovations in the latter half of the 20th century allowed more ubiquitous air conditioner use. In 1945, Robert Sherman of Lynn, Massachusetts, invented a portable, in-window air conditioner that cooled, heated, humidified, dehumidified, and filtered the air.^[13] The first inverter air conditioners were released in 1980–1981.^[14][15]

Documentation of the urban heat island effect

Further information: Luke Howard § Later meteorological work

The urban heat island effect was first scientifically noted by Luke Howard in the 1810s, who described London being several degrees warmer than its rural surroundings at night. The phenomenon gained attention in the late 1960s, mainly in Japan and North America.^[16][17]

Air conditioning linked to heat island effect

From the late 1980s to early 2010s, studies began to link air conditioners to the urban heat island effect.^[18][19][20] The phenomenon was observed in various cities such as Tokyo and Houston.

In 2016, an estimated 1.6 billion air conditioning units were in use worldwide, with a total cooling capacity of 11,675 gigawatts.^[21][22] The International Energy Agency predicted that the number of air conditioning units would grow to around 4 billion units by 2050.^[21]

Problem

The problem mainly stems from the co-existence of cooling demand and the nature of the cooling systems worsening climate change.

Cooling demand

In today's world, cooling is vital. A 2021 report estimated that around 345,000 people aged 65 and older died in 2019 from the heat, which is preventable with air conditioning. An estimated 190,000 heat-related deaths are averted annually owing to air conditioning.^[3][4]

Cooling systems

However, air conditioning is incredibly inefficient. The majority of active cooling systems are less than half as efficient as the most efficient ones, meaning heatwaves could lead to strained power grids, and in extreme cases, cause power outages, which could prove to be problematic as air conditioning can also affect how humans respond to heat, making humans more vulnerable to heat-related sicknesses and fatalities without artificial cooling.^[3]

In addition, the energy source of air conditioners are likely to be non-renewable. Air conditioners contribute 4% of global greenhouse gas emissions, which amounts to twice as much as the aviation industry.^[3]

The HFC coolants in air conditioners also contribute to climate change. Being listed as a high GWP material, this type of coolant can trap 150-5000 more heat than carbon dioxide if it escapes into the atmosphere.^[3]

Air conditioning units also contribute to pollution as they are difficult to disassemble or repair. Separating metal and plastic at the end of a unit's life cycle is also costly and not practical, meaning units are frequently disposed of.^[4]

Solutions

The solution to the air conditioning paradox lies in meeting the demand for cooling while not contributing any more to climate change. Alternatives to conventional air conditioning are currently being explored by governments and researchers. Already, more passive cooling techniques have been utilized to solve this issue.

Natural solutions

See also: Passive cooling

Natural solutions do not require energy for cooling purposes, and are therefore a very attractive solution. Many ways to achieve this have been explored.

The structure of a building can help dissipate heat. For example, in Zimbabwe, Eastgate Development cut its energy use by 90% by utilizing termite mound inspired structures.^[2]

The Chicago City Hall's green roof

Coverage of windows can help reduce internal heat gain from sunlight. The U.S. Department of Energy estimates that window awnings can lower internal heat gain from sunlight by up to 77%.^[2]

The coating of roofs have also seen great success. In the United States, painting roofs white has been shown to lower roof temperatures by as much as 30 °C. Meanwhile, in China, a project involving the installation of green roofs — roofs covered with vegetation — not only reduced the cooling demands of buildings, but also lowered the average land surface temperature in the area by 0.91 °C.^[2]

Planting trees can also help mitigate the heat island effect. A study in Europe discovered that tree cover can reduce land surface temperatures in cities by as much as 12 °C during the summer. In the United States, another study found that when tree cover reaches 40%, ground-level temperatures were lowered by nearly 6 °C.^[2]

Renewable energy

As renewable energy becomes cheaper^[23] and more popular, the energy source of air conditioners is shifting towards more renewable energy sources.^[2] This reduces the amount of carbon emissions resulting directly from generating electricity.

Low-GWP refrigerants

The danger of high-GWP refrigerants, such as HFCs, escaping into the atmosphere and trapping heat can be mitigated through development of low-GWP refrigerants.^[3]

See also

• Air conditioning