Science & Tech Correspondent
Winston Churchill once said, “The farther back you look, the farther forward you are likely to see.” While Churchill devised this expression for political history, his logic can be applied to geology: scientific models and climate patterns of the past millions of years indicate that the Earth should currently be undergoing a period of cooling, which is in direct contrast to the warming it is actually experiencing. Geologists and environmental scientists have identified humans as the primary source for this drastic discrepancy in climate, which they deemed so influential that a new geological era was named: The Anthropocene.
The Anthropocene refers to the current period of human influence on the environment, which is chiefly caused by unprecedented atmospheric carbon dioxide levels from burning fossil fuels, including coal, oil and natural gas. These resources have indeed become cheap and largely relied-on sources of energy, but consuming them for centuries on a global scale poses two big problems: one, fossil fuels are non-renewable natural resources, and two, burning fossil fuels produces large amounts of carbon dioxide.
The atmospheric carbon dioxide concentration surpassed 400 parts per million (ppm) in March of 2015, and the level currently sits at 404.42 ppm. For over 400,000 years, the atmospheric content of its concentration has never exceeded 300 ppm, and in 65 years it shot up 43 percent from 280 ppm in 1950 to 404 ppm in 2016.
Correlated to this is the global consumption of fossil fuels and the Earth’s increasing global temperature, which has risen 0.87 degrees Celsius (1.6 degrees Fahrenheit)since 1880.
Carbon dioxide belongs to a category of gases called “greenhouse gases,” which include carbon dioxide, methane, nitrous oxide, water vapor and ozone. Just like a greenhouse is to plants, these gases act like a blanket for the Earth, making it difficult for heat to escape. Specifically, as the sun emits solar radiation, it is absorbed by the Earth’s land and water.
The Earth then emits infrared (IR) radiation back into the atmosphere. Greenhouse gases slow the escape of this IR radiation, i.e. heat, from the atmosphere, causing it to accumulate and warm the planet.
Carbon dioxide comprises 64 percent of greenhouse gases in the Earth’s atmosphere, and its molecules follow a pattern of absorption/reemission of heat that causes global warming. As IR radiation moves out of the atmosphere, carbon dioxide molecules absorb and then reemit this energy, only for that same energy to be absorbed and reemitted by other carbon dioxide molecules; the cycle repeats, prolonging heat’s escape from the atmosphere.
Further, this warming has already altered the Earth’s global climate to the point of causing harmful environmental changes.
Rising sea levels and increased frequency of natural disasters are perhaps the most significant effects of climate change.
Rising sea levels are caused by melting glacier ice caps and thermal expansion, which is the physical expansion of water molecules after they increase in temperature. Sea levels have already risen eight inches since 1880 and are projected to rise three to six feet by the end of the 21st century.
This would deem many coastal regions and cities, such as Florida, New York and even London, unlivable because of being literally submerged in water.
Droughts have already intensified in the southwestern United States, causing large-scale agricultural dilemmas. In addition, wildfires, heat waves, category four and five hurricanes and widespread extinction of both terrestrial and aquatic species are expected to become more frequent by the year 2100.
While environmental scientists cannot look into the past to learn exactly how the Earth will look after experiencing the Anthropocene, future generations of humans can use these years as a lesson for the future.