According to the graph on PlantSeed.com, the carbon dioxide (CO2) levels peaked at roughly 288 parts per million (ppm) 410,000 years ago, 300 ppm 325,000 years ago, 278 ppm 245,000 years ago, and 282 ppm 130,000 years ago (SEED, 2014). The graph shows that at “present” (which could be anywhere from the last five hundred years), the carbon dioxide levels are at approximately 378 ppm (SEED, 2014). The website CO2Now.org (2014) shows that on March 14, 2014, the CO2 levels were 398.03 parts per million. Compared to the peak levels of carbon dioxide in the atmosphere over the course of the last 500,000 years, the present levels of carbon dioxide levels are significantly higher than any other trend the earth has seen. Not only are these levels at an all-time high for the last 500,000 years, but also they are above safe levels (CO2Now.org, 2014). The upper limit of the safety range for CO2 levels is 350 parts per million (CO2Now.org, 2014), but at 398.03 parts per million today we have exceeded the safety zone and are now in a dangerous situation.
Humans contribute significantly to the levels of carbon dioxide in the environment. There are three main factors that contribute to the increasing levels of carbon dioxide in the environment: electricity, transportation, and industry (EPA.gov, 2014). The use of electricity is one of the leading ways in which humans function in the daily world. Electricity is used to light homes and offices, provide heat, cook food, and more. Fossil fuels, such as coal, oil, or natural gas, are used to generate electricity, contributing to the leading source of carbon dioxide emissions in the United States (EPA.gov, 2014). The next leading cause of increased carbon dioxide emissions is transportation (EPA.gov, 2014). Gasoline and diesel fuels are used to power cars, trucks, trains, boats, and planes, contributing significantly to the amount of carbon dioxide released into the environment (EPA.gov, 2014). The third most prominent human cause of carbon dioxide in the atmosphere is industrial production (EPA.gov, 2014). Many industries use extreme processes of refining chemicals and products, which generates waste products, often in the form of carbon dioxide (EPA.gov, 2014). In addition, industrial production also uses vast amounts of electricity, doubly contributing to the carbon dioxide problem (EPA.gov, 2014).
As humans add large quantities of carbon dioxide into the atmosphere, other organisms are desperately trying to make up for the difference. Plants such as grass, shrubs, trees, and algae use carbon dioxide in the process of photosynthesis, which converts the energy from the sun into food for the living plant (SEED, 2014). Plants require carbon dioxide in order to survive and help in the process of taking carbon dioxide out of the atmosphere (SEED, 2014). Carbon dioxide is also removed from the atmosphere via the ocean (SEED, 2014). When air comes in contact with the ocean water, the air dissolves into its baser atomic elements and carbon dioxide dissolves into the ocean (SEED, 2014).
Deforestation is a problem that compounds the increasing levels of carbon dioxide in the atmosphere. Deforestation consists of cutting down and often burning or otherwise repurposing the wood from trees to make consumer goods. By burning the wood, branches, and leaves, carbon dioxide is released into the atmosphere (SEED, 2014). Also, because these trees are being killed, the trees no longer pull carbon dioxide out of the environment to use it in the process of photosynthesis (SEED, 2014). Therefore, more carbon dioxide is being added to the atmosphere and less is being removed because there are fewer plants to do the job.
Many people believe that the increased levels of carbon dioxide in the environment are a natural occurrence– and they are correct. According to the graph on the SEED website (2014), spikes in carbon dioxide levels do occur roughly every 75,000 years or so. It is also true that at the present moment (and for the past 500 years, approximately), we have been due for another one of these naturally occurring spikes in environmental carbon dioxide levels. However, the carbon dioxide levels we are seeing in the modern era are far higher than any previous spikes in carbon dioxide. So what is the difference this time? The Industrial Revolution changed the way the surface of the earth looks, the way the earth functions, and the way the organisms that live on the earth survive. The Industrial Revolution was a human event and not one that would have naturally occurred without human intervention. Therefore, humans are certainly contributing to global warming and the dangerously high levels of carbon dioxide in the atmosphere. Had humans not had the Industrial Revolution, we may well be living during a naturally occurring spike in carbon dioxide levels. However, those naturally occurring levels would be on par with historical trends from the last 500,000 years. The fact that our present carbon dioxide levels are absurdly high proves that human involvement has contributed significantly to the global warming event.
CO2Now.org. (2014). Earth's CO2 home page. CO2Now. Retrieved from http://co2now.org/
EPA. (2014). Overview of Greenhouse Gases. The United States Environmental Protection Agency. Retrieved from http://www.epa.gov/climatechange/ghgemissions/gases/co2.html
SEED Staff. (2014). Global climate change and energy. Schlumberger Excellence in Educational Development. Retrieved from http://www.planetseed.com/sciencearticle/global-climate-change-and-energy