Atmosphere Composition & Processes
Atmosphere Outcomes
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Describe the basic composition of Earth\’s atmosphere?
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Explain the cause and effects of ozone depletion and acid rain?
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Describe how the greenhouse effect is critical in maintaining Earth\’s climate?
The Earth\’s atmosphere is a combination of gases, including nitrogen, oxygen, and many others. This illustration is just showing a few relevant to our course topics.
Many of these gases are not directly utilized by humans, although we may need some of the nutrients (like nitrogen) to eventually reach us through the food web.
The Earth has a layered atmosphere, with different densities and composition of gases.
For example, there is a higher amount of ozone in part of the stratosphere than in other layers.
From the illustration above, which atmospheric layer do humans primarily live within?
Human impacts on the atmosphere
Chlorofluorocarbons (CFCs) were thought to be relatively harmless molecules, and were used as refrigerants and propellants (in things like cans of hairspray).
CFCs entered the stratosphere and reacted with the ozone molecules, tearing them apart. It turned out that ozone was reducing the amount of ultraviolet light that reached the earth\’s surface.
Ultraviolet light can cause mutations, and increased levels impacted a wide range of organisms. In humans, the areas most impacted by ozone depletion (for example in New Zealand), has higher rates of cataracts (vision loss) and skin cancer.
Which two molecules can react with water to form acid rain? _____ and _____
What are two possible impacts of acid rain, also caused acid deposition?
The Greenhouse Effect
Before we talk about how Earth\’s climate is generated, it is important to distinguish between weather and climate.
Specific weather can be difficult to predict more than a week in advance, and that gives an indication of how challenging it is to create long-term climate models.
Instead of specifically predicting a day\’s temperature or a week\’s precipitation, climate models plot anticipated trends based on accumulated weather events over time.
Our climate is created by atmospheric gases that retain heat. From the figure, what are some of these gases?
Too high of a concentration of greenhouse gases leads towards an atmosphere more like Venus; too low of a concentration is more like Mars.
List three human activities that can increase the amount of greenhouse gases in the atmosphere.
We\’ll have more on how climate impacts producers in next week\’s lectures.
Check your knowledge. Can you:
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Describe the basic composition of Earth\’s atmosphere?
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Explain the cause and effects of ozone depletion and acid rain?
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Describe how the greenhouse effect is critical in maintaining Earth\’s climate?