IB ESS Topic 6.2 Stratospheric ozone

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What is stratospheric ozone?

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Stratospheric ozone is a layer of ozone (O3) located in the stratosphere, approximately 10 to 30 miles above the Earth's surface, that absorbs the majority of the sun's harmful ultraviolet (UV) radiation.

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What causes the formation of ozone holes?

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Ozone holes are primarily caused by the release of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS) that break down ozone molecules, particularly in polar regions.

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What is the global distillation effect?

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The global distillation effect refers to the process by which volatile substances, like CFCs, evaporate in warmer regions and condense in colder regions, leading to higher concentrations of these substances in polar areas.

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How do CFCs affect ozone production?

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CFCs release chlorine atoms when exposed to UV radiation, which then catalyze the breakdown of ozone (O3) into oxygen (O2), reducing the ozone layer.

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What is the Montreal Protocol?

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The Montreal Protocol is an international treaty signed in 1987 aimed at phasing out the production and consumption of ozone-depleting substances, including CFCs.

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What are the ecological consequences of reduced stratospheric ozone?

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Ecological consequences include increased UV radiation leading to loss of biodiversity, collapse of marine food webs, and reduced productivity in terrestrial biomes.

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Which of the following is NOT an ecological consequence of reduced stratospheric ozone?

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Reduced crop yield is not considered a direct ecological consequence of reduced stratospheric ozone.

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What role does UV radiation play in ozone depletion?

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UV radiation is responsible for breaking down CFCs, releasing chlorine atoms that catalyze the destruction of ozone molecules.

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What is the significance of the ozone layer?

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The ozone layer protects life on Earth by absorbing the majority of the sun's harmful UV radiation, which can cause skin cancer and cataracts in humans and harm ecosystems.

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What is a chlorine atom's role in ozone depletion?

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A chlorine atom, released from CFCs, can destroy thousands of ozone molecules before it is removed from the stratosphere.