In his book Pale Blue Dot: A Vision of the Human Future in Space, Carl Sagan famously described planet Earth as follows:
“Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species lived on a mote of dust suspended in a sunbeam" (Sagan, 1994).
Earth as a "Pale Blue Dot" taken from the Voyager 1 Space Probe. Source: Interesting Engineering
Essentially, Sagan described Earth as the one-and-only home of all of mankind throughout history. In the beginning of Earth’s 4.6 billion-year-old history, the atmosphere on Earth was extremely hot and volatile, with toxic gases like hydrogen sulfide, methane, and carbon dioxide comprising the atmosphere. However, as the Earth began to cool down over the next half-billion years, the atmosphere solidified enough for water to be able to get retained. As a matter of fact, the atmosphere on Earth cooled to such an extent that the first Ice Age emerged, albeit after a further billion years.
Between about 2.7 to 1 million years ago, it was predicted that Ice Ages occurred every 41,000 years due to Earth’s variable orientation with the other planets around our solar system. However, in the last 800,000 years, periods of glacial expansions have occurred much less frequently - at about every 100,000 years or so. It is estimated that about every 100,000-year cycle, polar ice sheets grow for about 90,000 years, while a further 10,000 years are needed for the ice sheets to completely melt during the warmer glaciation cycles.
The entire Earth encompassed by ice sheets during an Ice Age. Source: Live Science
Given that the last Ice Age occurred 11,700 years ago, we should be expecting a new Ice Age any minute now, right? Unfortunately, anthropogenic activities within the last 200 years have severely impacted the glaciation cycle for the next Ice Age and beyond. Especially beginning with the Industrial Revolution, the environment on Earth has continuously experienced a rapid increase in temperature globally. Below is a picture of one of the many factories during the Industrial Revolution. Although factories are efficient in mass-producing manufactured goods, they are highly potent for Earth's nature as they emitted greenhouse gases in the atmosphere, which further increased Earth's global temperature. Even in modern society, industrial activities are emitting ever-increasing amounts of greenhouse gases (primarily CO2) that accumulate and remain stored in the atmosphere. If these greenhouse gases continue to get emitted, the next Ice Age may never form, which will subsequently prompt glaciers on Earth to continue melting, further raising the global sea level.
Image of factories emitting greenhouse gases during the Industrial Revolution. Source: History
The urban heat island effect is a direct result of both industrial activities and urbanization. Since the Industrial Revolution, the rise of urban sprawl has yielded a severe increase in temperatures worldwide, especially in urban centers. An urban heat island is formed in the presence of densely compacted infrastructures that limit the ability for cool air to flow freely within an urban area. The lack of air movement facilitates the accumulation of excess heat stored by impervious surfaces into the atmosphere. Additionally, the reduction of vegetation in response to urbanization further weakens the cooling capacity of cities as fewer trees will be able to provide shade from sunlight.
As the human population becomes increasingly urbanized, it is imperative to document the formation of urban heat islands because they pose a severe threat to social and environmental justice. Unfortunately, many studies have documented an unequal distribution of heat exposure between underserved communities and affluent communities as underserved communities tend to be disproportionately more vulnerable to heat-related illnesses. This trend is largely due to the fact that underserved communities are often concentrated within developing regions that have a lack of access to urban-cooling adaptations. The unequal distribution of urban heat island effects also creates public health concerns, especially in communities that are marginalized in densely clustered city centers. Among the most alarming public health concerns is air pollution from industrial activities as exposure to harmful air pollutants, like particulate matter and CO2, can increase mortality in the long run due to their ability to accumulate in the atmosphere for long periods of time.
Visual depiction of the urban heat island effect. Source: DOZR
Although reverting back to Ice Age is an extreme form of urban cooling that will cool down global temperatures but also dramatically change ecosystems on Earth, the fact of the matter is that the urban heat island effect must be reduced at all costs to mediate the harmful effects of global warming. Mitigating the urban heat island effect and cooling down temperatures, albeit not to the degree of inducing another Ice Age, are not mutually exclusive goals. By investing in alternative sources of renewable energy, such as photovoltaics and hydropower, the urban heat island effect can be substantially reduced to the point wherein the normal glaciation cycles on Earth can continue and sea levels won’t rise to extreme levels. All in all, investing in renewable energy is an investment in the future of the Earth as a whole, and the quicker society starts investing in renewable energy, the less damage can be done to the future of our planet.
About The Author
As a graduate student at San Jose State University, I aspire to research on the social and environmental interrelationships between photovoltaics and urban green spaces in mitigating the urban heat island effect. Having the opportunity to be a Solar Ambassador for RE-volv empowered me to spread awareness about the importance of adopting solar energy as the primary source of energy for the present and future. Through my experience as a Solar Ambassador for RE-volv, I was so blessed to have the opportunity to organize tabling events at San Jose State University and aided in the fight to adopt a more sustainable future for generations to come!
