Sea ice in the Artic has been observed melting faster than it re-freezes in winter. The National Oceanic and Atmospheric Administration has found out that the average annual air temperature in the Artic is 1.9C above the long-term average that was recorded between 1981 and 2010. This warmer condition has caused a delay in the formation of ice in winter and triggered the earlier melting of sea ice in summer. In the United States, 2019 was recorded to be the second-hottest year ever. Recently, the bushfire crisis in Australia has destroyed more than 10 million hectares of bush, forest and parks, slaughtering approximately half a billion animals. Acknowledging these devastating events, many experts have been pointing the finger at global warming, arguing that the rising global average temperature has been a cause of many of these unprecedented natural calamities. According to The World Meteorological Organization, people are expected to experience much extreme weather over the span of 2020 and the coming decades in response to record levels of greenhouse gases (GHG) trapped in the atmosphere. However, many industries have started adopting environmentally-friendly practices, with the residential construction sector materializing an extraordinary idea in relation to home.
1. Global warming and greenhouse gases
In the atmosphere, heat-trapping gases are known as greenhouse gases. It was recorded that carbon dioxide (CO2), followed by methane, nitrous oxide and fluorinated gases, accounted for 82% of the total emissions in 2017. CO2 remains in the atmosphere longer than the other types of gases. When a pulse of CO2 is emitted, around 40% of the emission will reside in the atmosphere for 100 years, 20% will remain for approximately 1000 years and 10% will require more or less 10,000 years to turn over. Molecules of CO2 are capable of absorbing energy from infrared radiation and re-emits it some time later. Upon absorbing an incoming infrared photon, a molecule of CO2 vibrates due to the energy transferred from the photon. The molecule, subsequently, gives up the extra energy by emitting another infrared photon, ceasing its vibrating motion. In the real-world process, CO2 molecules will bump into other gas molecules prior to re-emitting the infrared photons, transferring the energy they have gained to the other gas molecules, triggering their motion. Theoretically, the temperature of a gas is related to the speed of the molecules within the gas, with an increase in the motion of the molecules resulting in a rise in the temperature of the gas.
2. Home’s electricity use is related to GHG emissions
In 2016, the U.S. domestic sector generated around 19% of the total national greenhouse gas emissions, 69% of which was the result of electricity use. In addition, 32% of the GHG emissions due to electricity use was related to home heating through direct fossil fuel combustion. Considering these staggering figures, it becomes evident that making homes energy efficient will result in a significant GHG emission reduction.
3. Adoption of passive solar home design to reduce GHG emissions
Through its external envelope, a passive solar home is capable of collecting, storing, reflecting and distributing solar energy in the form of heat in winter and refusing solar heat in summer. Being like a thermos but with good ventilation, a passive solar home needs to be air-tight, have continuous and proper insulation, triple-panel windows and a good air quality control system. The design has to eliminate a phenomenon known as thermal bridging, which occurs when a material, having a higher temperature, transfers its thermal energy, to an adjacent material, having a lower temperature. By sealing off the interior of its space thermally, the internal temperature of a home, by default, is more stable. Objectively, the design of a passive solar home requires the consideration of, during the design stage, the building location and orientation, building layout, window design, insultation, thermal mass, ventilation system and shading. Ultimately, both the design and construction have to be undertaken by qualified designers and contractors, such as framing and roofing contractors.
Experts have stated that this natural phenomenon will continue to cause havoc globally until the intensity is diminished. However, successfully solving global warming, which has been in existence for a long period of time, requires all people to take actions to reduce their GHG emissions. Just by building a passive home as opposed to a conventional one, it is possible to reduce these emissions by a great amount.