Through the Earth’s geological history, it has often been frozen in the grips of various ice ages, interrupted with brief warming periods. For the past 10,000 to 50,000 years, the Earth has been enjoying the latest period of global warming. The Earth’s surface temperature is protected by its atmosphere, of which carbon dioxide (CO2) is a major component. There is a strong relationship between CO2 and the surface temperature on Earth. CO2 levels would naturally rise as the Earth warms up. However, over the past 200 years, humans have contributed to CO2 levels rising dramatically, way above even the highest historical levels, and this has hastened global warming.
Lutgens and Tarbuck (2014) explain that the Earth’s atmosphere greatly influences its surface temperature and its life-giving environment. The major components of the atmosphere are nitrogen and oxygen, composing about 99% of the atmosphere. The next major component is carbon dioxide (CO2). Additional variable components are water vapor, aerosols, and ozone (O3). Both water vapor and CO2 act like a greenhouse by conserving the heat emitted from the Earth. Aerosols are solid and liquid particles that float in the atmosphere and can either reflect or absorb the sun’s radiation. Two examples of an aerosol are man made pollution or ash from a volcanic eruption. These aerosols can reduce the temperature on Earth, because they effectively block sunlight from reaching the Earth’s surface. Ozone sits on the stratosphere like a layer. This layer of ozone absorbs the sun’s harmful ultraviolet (UV) radiation. Each component of the atmosphere guards the Earth’s current habitable state.
CO2 is released and absorbed into the atmosphere as part of the carbon cycle. CO2 is emitted from respiration, decay and volcanoes. It is absorbed into plant life, dissolves into the oceans, or becomes part of the atmosphere (Lutgens and Tarbuck, 2014; SEED, 2013). When animals including humans respire or breathe, they take in oxygen (O2) and exhale CO2. When animals and plant life decay, they break down to simpler compounds including CO2. CO2 is released by volcanic eruptions. On the other side of the cycle, plant life absorbs CO2 during photosynthesis. Water, including the Earth’s oceans, naturally dissolves CO2. It is more soluble at lower temperatures and higher pressure (SEED, 2013). Colder, deeper oceans, ice or snow hold more CO2 than warmer waters. Any excess CO2 stays in the atmosphere.
When the Earth warms up, CO2 levels also increase naturally. When the Earth cools down, CO2 levels decrease. In the past 450,000 years, the CO2 concentration in the Earth’s atmosphere...