The Greenhouse Effect
The carrying capacity of the Earth is defined as the largest possible population that the Earth would be able to support without having to reduce its current lifestyle. Certain factors that affect the carrying capacity include the supply of drinkable water, fundamental resources in the environment, and the rapid degradation of land.
According to the research performed by Ehrlich, the concept of carrying capacity can be expressed by the equation I=PAT. This equation is used to show the impact the human population has on the Earth. I=impact, P=the population’s size, A=the per-capita consumption, and T=the environmental damage inflicted by technologies. With the current population of about 5.5 billion and growing at an annual rate of 1.7%, it is clear that the Earth will face tremendous shortages of resources. Earth is overpopulated by millions of people and the environment has already passed it maximal load.
If the human population continues to grow and the current standard of living does not change, the environment will continue to suffer. The world’s energy profile consists of burning millions of tons of fossil fuels every year, as it is still the main source of energy for the human population.
The IPCC publishes a report that focuses on potential environmental issues that arise from climate change. As the world continues to burn fossil fuels at rapid amounts, snow cover and sea ice decrease which lead to a rise in sea level, precipitation events such as rain storms and hurricanes increase in intensity, and there is a tendency for drying in certain areas which lead to more droughts. Increasing amounts of CO2 in the atmosphere lead to an increase in acidification in the ocean. Temperature extremes will become more intense, frequent, and longer lasting causing areas of increased population to use more fossil fuels in order to survive.
The greenhouse effect is a controversial issue that many humans don’t quite understand. Many humans believe that the greenhouse effect is a positive problem because life on earth depends on the sun and the heat that the atmosphere traps. However what humans don’t recognize is the difference between the natural and anthropogenic greenhouse gases.
If there were no “man-made” or anthropogenic gases produced in the world then the greenhouse effect wouldn’t be an issue but the reality is that humans are continuing to burn fossil fuels at a alarming rate. Figure 3 below shows the global anthropogenic greenhouse gas emissions by type. The main greenhouse gas is carbon dioxide, CO2 . It makes up about 57% of all anthropogenic greenhouse gas emissions. Figure 4 indicates that carbon dioxide comes from the burning of natural gas, petroleum, and coal from power stations, transportation, and industrial processes.
The other two main greenhouse gases produced by humans are methane (CH4) and nitrous oxide (N2O). Methane makes up roughly 14% and nitrous oxide about 8% of the anthropogenic greenhouse gas emissions. Methane and nitrous oxide are produced by agricultural byproducts as indicated in figure 4. Fossil fuel retrieval, processing, and distribution also produce methane. Waste disposal and treatment are also major contributors to methane production. Nitrous oxide’s other major contributor is land use and biomass burning which contributes about 26% of all nitrous oxide produced.
As specified above in figure 3, the last 1% of global anthropogenic greenhouse gas emissions comes from various fluorocarbons (F-carbons). Fluorocarbons are released into the atmosphere from industrial processes.
Figure 4. Anthropogenic Greenhouse Gas Emissions by Gas
(Million Metric Tons of Carbon Equivalent)
The greenhouse gases produced from humans have a value that is used to compare the various greenhouse gases and the ability of them to trap heat in the atmosphere. The value produced is called Global Warming Potential (GWP). All the gases are compared against carbon dioxide, which has a value of 1. Figure 5 below shows main greenhouse gases and their GWP. It also shows the impact the greenhouse gases will have on global warming over various periods of time.
Figure 5: Global Warming Potential for main greenhouse gases
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