Changes in the Atmosphere
From a human perspective, Earth’s atmosphere is enormous. However, compared to the size of the Earth, it is just a thin layer of gases surrounding the Earth like a blanket. Despite its relatively small size, Earth’s atmosphere is extremely important in regulating Earth’s temperature and blocking solar radiation, which are both vital to all forms of life. With over seven billion people on Earth and a growing demand for energy, food, and all natural resources, Earth’s atmosphere is changing. Due to the interconnectedness of Earth’s systems, it is difficult for scientists to predict the exact range and effects of these changes, but the scientific community is confident that these changes are occurring and some very quickly.
Natural Climate Change
You may think that all atmospheric changes are caused by human activities. This is not true. Processes, such as the movement of water by ocean currents, or volcanic eruptions, can also create climate change. Climate change by natural processes can be both short-term and long-term. View this activity to learn about several natural processes that have an impact on climate. Click the player button to begin.
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Human Influenced Climate Change
No scientists will disagree with the fact that human activities have negative consequences for our atmosphere. The largest source of air pollution results from the burning of fossil fuels. Air pollution can occur in two different ways. Primary pollution occurs when dangerous chemicals are injected directly into the atmosphere. Secondary pollution occurs when the primary pollutants undergo a chemical reaction to create a new form of pollution. In this interactivity, you will investigate both primary and secondary pollution that are the direct result of human activities. Click the player button to begin.
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The Ozone Hole
Courtesy of NASA
Thinning ozone layer over Antarctica.
Ozone (O3) is a gas found throughout all the layers of Earth’s atmosphere. The stratosphere is unique in that it contains a layer of highly concentrated ozone gas, called the ozone layer. The ozone layer is a critical component of the atmosphere since it blocks harmful UV radiation from the Sun. In the 1970s, scientists noticed a place in the atmosphere over Antarctica where the ozone layer was thinning. This became known as the hole in the ozone layer, although it as not technically a hole. Chlorofluorocarbons (CFCs) are responsible for the thinning of the ozone. CFCs are chemicals used in aerosols and refrigerants such as Freon®. When released into the atmosphere, CFCs bond with molecules of oxygen, breaking up the ozone molecules. More than 150 countries came together to sign the Montreal Protocol in 1987, which agreed to phase out using these chemicals over time. In 2007, 191 countries agreed to phase out another category of pollutants harmful to the ozone layer. Scientists have seen improvement in the ozone layer as a result of these international treaties, but CFCs are very long-lasting chemicals and it will take generations to repair the damage to the ozone layer. The image above shows the thinning ozone layer located over Antarctica. The blue and purple colors represent a lack of atmospheric ozone.
Global Warming
Global warming takes place as the lower levels of the atmosphere increase in temperature. As the Earth warms, sea ice melts and sea level rises. The changes in temperature and the impact it has on the Earth is called global climate change. Due to the burning of fossil fuels, the Earth is trapping more heat in the atmosphere and warming. View this presentation to learn how the atmosphere is heated, traps radiation, and how greenhouse gases are responsible for the warming of the planet. Click the player button to begin.
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Changes in the Atmosphere Review
Now that you explored changes in the atmosphere, practice what you have learned. In this non-graded activity, read each question and select the correct response. Click the player button to get started.