IB Environmental systems and societies Topic 6.1A Atmosphere Revision Notes (SL/HL)

IB Environmental systems and societies Topic 6.1A Atmosphere Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

The Atmosphere: Earth's Life-Support Envelope

The atmosphere is a multilayered, dynamic envelope of gases, liquids, and suspended solids surrounding Earth.
It forms the outer limit of the biosphere, separating the planet from outer space.
Its composition and structure make life possible by regulating temperature, filtering radiation, and moving energy and gases around the planet.
It exchanges gases and energy continuously with the lithosphere, hydrosphere, and biosphere.

Analogy

The atmosphere works like Earth's life-support system, holding temperature steady, shielding the surface from radiation, and circulating the gases living things need.

Composition: A Stable Mix Dominated by Nitrogen and Oxygen

Up to about 80 km, the atmosphere holds a fairly constant mixture of gases.
These gases drive climate regulation, respiration, and ecological balance.

Gas	Percentage	Importance
Nitrogen (N₂)	~78%	Maintains atmospheric pressure, essential for the nitrogen cycle
Oxygen (O₂)	~21%	Supports respiration and combustion
Argon (Ar)	~0.9%	Inert; contributes to total atmospheric mass

Trace Gases (Under 0.1%)

Carbon dioxide (CO₂), ~0.04%: drives photosynthesis and warms the surface through the greenhouse effect.
Water vapour (H₂O): drives weather, cloud formation, and precipitation.
Ozone (O₃): concentrated in the stratosphere, where it absorbs harmful UV radiation.
Methane (CH₄) and nitrous oxide (N₂O): potent greenhouse gases that affect climate.

Suspended Particles

Common examples include dust, ash, soot, sea salt, and other aerosols.
They scatter sunlight, seed cloud formation, and affect air quality.

Tip

Even at tiny concentrations, CO₂ and other greenhouse gases have a massive influence on global climate.

Structure: Five Layers Defined by Temperature

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The Atmosphere: Earth's Life-Support Envelope

The atmosphere is a multilayered, dynamic envelope of gases, liquids, and suspended solids surrounding Earth.
It forms the outer limit of the biosphere, separating the planet from outer space.
Its composition and structure make life possible by regulating temperature, filtering radiation, and moving energy and gases around the planet.
It exchanges gases and energy continuously with the lithosphere, hydrosphere, and biosphere.

Analogy

The atmosphere works like Earth's life-support system, holding temperature steady, shielding the surface from radiation, and circulating the gases living things need.

Composition: A Stable Mix Dominated by Nitrogen and Oxygen

Up to about 80 km, the atmosphere holds a fairly constant mixture of gases.
These gases drive climate regulation, respiration, and ecological balance.

Gas	Percentage	Importance
Nitrogen (N₂)	~78%	Maintains atmospheric pressure, essential for the nitrogen cycle
Oxygen (O₂)	~21%	Supports respiration and combustion
Argon (Ar)	~0.9%	Inert; contributes to total atmospheric mass

Trace Gases (Under 0.1%)

Carbon dioxide (CO₂), ~0.04%: drives photosynthesis and warms the surface through the greenhouse effect.
Water vapour (H₂O): drives weather, cloud formation, and precipitation.
Ozone (O₃): concentrated in the stratosphere, where it absorbs harmful UV radiation.
Methane (CH₄) and nitrous oxide (N₂O): potent greenhouse gases that affect climate.

Suspended Particles

Common examples include dust, ash, soot, sea salt, and other aerosols.
They scatter sunlight, seed cloud formation, and affect air quality.

Tip

Even at tiny concentrations, CO₂ and other greenhouse gases have a massive influence on global climate.

Structure: Five Layers Defined by Temperature

Definition

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(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

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Note

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Excepteur sint occaecat cupidatat non proident

Tip

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Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
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Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

IB Environmental systems and societies 6.1A Atmosphere Notes

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

The Atmosphere: Earth's Life-Support Envelope

Composition: A Stable Mix Dominated by Nitrogen and Oxygen

Trace Gases (Under 0.1%)

Suspended Particles

Structure: Five Layers Defined by Temperature

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

The Atmosphere: Earth's Life-Support Envelope

Composition: A Stable Mix Dominated by Nitrogen and Oxygen

Trace Gases (Under 0.1%)

Suspended Particles

Structure: Five Layers Defined by Temperature

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account