With headlines in the daily news chronicling desiccating drought, tempestuous typhoons, and catastrophic conflagrations, the ubiquitous presence of these increasingly salient planetary perturbations graphically demonstrates the relevance of climate change as all-encompassing and here for the foreseeable future.
So, what is the science behind this issue, and what does it portend for humanity’s future?
The answer to the first question starts with an explanation as to what underlies these particularly menacing manifestations in nature.
Climate change is the result of another phenomenon known as global warming. Climatologists whose findings have been verified by the United States government have found that planet earth has warmed by approximately two degrees Fahrenheit since 1880, according to Climate.gov.
This warming of planet earth, known as global warming, has played out in changes to earth’s climate that have resulted in a variety of consequences for human civilization and life on earth. These changes in climate, which have come to be referred to as climate change, result from a phenomenon called “the greenhouse effect.” This effect refers to how the earth’s atmosphere traps heat from the rays of the sun.
How the greenhouse effect works can be seen in the way sunlight interacts with the earth and its atmosphere. When the sun’s rays pass through the atmosphere and bounce off the surface of the earth, they re-radiate at a longer wavelength than that at which they passed through the earth’s atmosphere upon entering. This longer wavelength is at a range of wavelengths known as infrared.
In contrast to the shorter wavelength of light that initially passes through the atmosphere, infrared rays that bounce back off the earth cannot pass through the atmosphere because the atmosphere is opaque to infrared wavelengths. As a result, these wavelengths become trapped between the atmosphere and the earth. And the more infrared wavelengths that are trapped, the hotter the temperature on earth becomes.
While too much heat can be problematic, atmospheric heat is a necessity for life on earth. Heating produced by the greenhouse effect is a natural process that is responsible for maintaining the planet’s stable temperature. Without it, the earth would be so cold that it would be uninhabitable for humans.
The risk to humans posed by global warming has arisen in large part due to the greenhouse effect’s heating mechanism when operating with a significant increase in carbon emissions. That is because a significant increase in these emissions thickens the earth’s atmosphere, blocking greater amounts of infrared wavelengths and thus trapping greater heat.
As an integral part of its sustainability, earth has had carbon in its atmosphere for more than four-and-a-half billion years. Its quantity is generally calculated in how many parts of carbon in the atmosphere there are per million. For the last 800,000 years, atmospheric carbon in parts per million, abbreviated as ppm, has fluctuated between approximately 200 and 300 ppm, according to Climate.gov.
This stable range of carbon concentrations destabilized when fossil fuel began to be used on a massive scale during the industrial revolution. Since then, fossil fuel use has infused the atmosphere with a surge of carbon emissions. Steadily increasing over time through to today, carbon levels in the earth’s atmosphere now register at 420 ppm, according to the National Oceanic and Atmospheric Administration.
The present-day increase in carbon emissions has come from human activity primarily in the form of the use of electricity provided by coal-fired power stations, as well as the use of petroleum-based gasoline. But how do we know this excess carbon was produced by humans?
The carbon that comes from burning fossil fuel has a different chemical composition than the carbon that exists in the atmosphere as a part of earth’s natural processes. By measuring how much of the carbon in the atmosphere has this specific chemical composition, scientists have been able to determine that most of the excess in carbon does indeed proceed from human sources.
So, if these excess carbon emissions from human sources increase global warming, and these in turn magnify changes in earth’s climate, what does climate change portend for humanity’s future?
To answer this question, I interviewed Tom English, PhD., who is an affiliate of the Environmental Protection Agency, the President of the Earth Restoration Team, and editor of the book Witness for the Earth: Coalescing the Religious Environmental Movement. English spoke of some portentous clues deep in earth’s distant past.
According to English, the earth has gone through five mass extinctions in three major geological eras: the Paleozoic, the Mesozoic and the Cenozoic eras. The Paleozoic era, the earliest of the three, came to an end 270 million years ago with a mass extinction event known as the End Permian Extinction. At this time, ninety-five percent of species on earth became extinct.
Because life on earth almost came to an end during the End Permian Extinction, the consequent ramifications are astounding: humans are at present engaging in activities the byproduct of which consists of carbon emissions at 200 times the rate of the End Permian Extinction, according to Curtin University’s School of Earth and Planetary Sciences, based in Western Australia.
English believes that we are now in a new, fourth geological era known as the Anthropocene. A similar statement cited by English was made by the Pope of the Catholic church, Pope Francis, who said, “We are not experiencing a change within an era. We are experiencing a change of eras.”
“The Anthropocene began when humans became the largest biological force on earth, which happened around 1950,” said English. “If we play our cards right, we can stop it. If not, we will have completed earth’s sixth mass extinction in this century.”
English believes that if there were to be a sixth mass extinction, humans would probably not survive it since they are at the top of the food chain.
The question, according to English, then becomes, “How do we stop making things worse, and start making them better?”
For context, English refers to Conference of Parties 21. In COP21, countries around the world convened and pledged to keep planetary temperatures from increasing beyond 1.5 degrees Celsius. According to scientific calculations put forth in this conference, carbon emissions from human sources must reduce by 1,000 gigatons by 2050 if humanity is to avoid being locked into an eventual mass extinction.
To demonstrate how this may be done, English cites Pope Francis’s book, Laudato Si’, in which the Pope proposes two solutions: 1) solve our physics problems, and 2) solve our social problems. English also believes in the need to “do it in a way that’s economical.”
As a means to these solutions, which English believes will be economically advantageous to the global economy, English draws from the book Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming,” edited by Paul Hawken. According to English, statistical calculations found in Drawdown show that through the construction of land-based windmills, photovoltaic solar farms, and rooftop solar, in addition to the use of electric vehicles, emissions can be reduced by 16% of the goal of 1,000 gigatons, saving the global economy $65 trillion dollars, which can then be put to solve the social problems referred to in Laudato Si’.
