United States of America 

Greenhouse Gases

What is a greenhouse gas? A greenhouse gas is any gas that traps heat in the atmosphere. Greenhouse gases are the leading cause of climate change. They create a blanket over earth in the atmosphere. Sunlight enters the atmosphere and some gets reflected off of the earth's surface and back out of the atmosphere. Some of the heat from the sun gets absorbed by the earth's surface. Eventually the heat absorbed by the earth's surface radiates back out. The greenhouse gases trap this heat and prevent it from leaving earth. This results in excess heat and a warmer climate. 

 

As seen in this chart, carbon dioxide (CO2) is the most common greenhouse gas. CO2 makes up 57% of all greenhouse gases from fossil fuels alone. Including the other sources of the gas, 77% of all greenhouse gasses are made up of CO2. Not only is there a lot of CO2 in the air, but according to Annenberg Learner-The Habitable Planet, CO2 has an atmospheric lifespan of up to 200 years. Meaning that some of the CO2 that was released into the air during the U.S. industrial revolution is still in the atmosphere today. As of right now, the CO2 levels in the air are higher than ever. With CO2 levels exceeding 380 parts per million they are higher than they have ever been for the past 650,000 years, according to Annenberg Learner-The Habitable Planet.

 

The sharp increase of greenhouse gasses in the past century is largely due to an increase in human industrialism. The burning of fossil fuels, which power much of our society, releases large amounts of CO2 into the air. Fossil fuels also release smaller amounts of other greenhouse gases such as nitrous oxide and methane, which are the second and third most common greenhouse gases. Why do other greenhouse gases not get as much attention as CO2? Mostly because there is not as much of these gases in the air, though fossil fuels do emit many other harmful gases, CO2 is the most abundant gas that is released when the fuels are burned. Additionally, most gases do not have as long of an atmospheric lifespan as CO2 does. (Annenberg Learner-The Habitable Planet)