6.4 Stratospheric Ozone (DP IB Environmental Systems & Societies (ESS): SL): Flashcards
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What is the relationship between wavelength and energy for electromagnetic radiation such as UV?
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Cards in this collection (40)
What is the relationship between wavelength and energy for electromagnetic radiation such as UV?
Shorter wavelengths of electromagnetic radiation have higher frequencies and more energy, making them more damaging to living organisms.
Define cataracts.
Cataracts are a clouding of the lens of the eye, caused by prolonged UV exposure, leading to blurry vision and eventual vision loss if untreated.
How does UV radiation increase the risk of skin cancer?
UV radiation damages the DNA in skin cells, causing uncontrolled cell growth and the formation of cancerous tumours.
True or False?
Sunburn is caused by the skin's inflammatory response to excessive UV exposure.
True.
Excessive UV exposure triggers an inflammatory response, causing the skin to become red, painful and sometimes blister.
How does chronic UV exposure affect the appearance of skin?
Chronic UV exposure breaks down collagen and elastin fibres, causing wrinkles, sagging skin and age spots.
UV radiation reduces rates in plants, decreasing crop yields.
UV radiation reduces photosynthesis rates in plants, decreasing crop yields.
Define phytoplankton.
Phytoplankton are photosynthetic organisms that convert sunlight, carbon dioxide and nutrients into organic matter, forming the base of aquatic food webs.
How does UV radiation damage phytoplankton?
UV radiation damages phytoplankton by causing DNA damage and reducing their photosynthetic activity and growth.
What effect does reduced phytoplankton productivity have on zooplankton?
Reduced phytoplankton productivity leaves zooplankton with less food available, affecting their growth and reproduction.
True or False?
A decrease in phytoplankton productivity has no effect on fish and marine mammals.
False.
Reduced phytoplankton and zooplankton availability cascades up the food web, affecting fish and marine mammals and reducing biodiversity.
How can UV radiation affect DNA during cell division?
UV radiation can induce mutations in DNA during cell division, disrupting normal cell growth and increasing the risk of cancer.
Wearing sunscreen with a high sun protection factor and seeking during peak sun hours help reduce the risk of UV-related health issues.
Wearing sunscreen with a high sun protection factor and seeking shade during peak sun hours help reduce the risk of UV-related health issues.
Define ozone.
Ozone (O3) is a molecule composed of three oxygen atoms, found mainly in the Earth's stratosphere.
Which type of UV radiation is completely absorbed by stratospheric ozone?
UVC radiation, the shortest wavelength and most harmful type, is completely absorbed by stratospheric ozone.
Which type of UV radiation is mostly, but not completely, absorbed by stratospheric ozone?
UVB radiation is mostly absorbed by stratospheric ozone, though some still reaches the Earth's surface.
True or False?
UVA radiation is the most harmful type of UV radiation.
False.
UVC radiation is the most harmful type; UVA has the longest wavelength and is the least harmful.
Define dynamic equilibrium in the context of stratospheric ozone.
Dynamic equilibrium is a steady state where the rate of ozone formation equals the rate of ozone destruction, keeping ozone concentration relatively stable.
What two products form when UV radiation causes an ozone molecule to break apart?
When ozone breaks apart, it forms an oxygen molecule (O2) and a free oxygen atom (O).
Ozone destruction and reformation occurs naturally in the stratosphere, forming a continuous cycle that keeps ozone concentration relatively over time.
Ozone destruction and reformation occurs naturally in the stratosphere, forming a continuous cycle that keeps ozone concentration relatively stable over time.
Define ozone-depleting substances (ODSs).
Ozone-depleting substances (ODSs) are chemicals that enhance the natural ozone breakdown process beyond natural levels, causing stratospheric ozone depletion.
Name one product group in which CFCs were previously used as propellants.
Chlorofluorocarbons (CFCs) were previously used as propellants in aerosol products such as sprays, foams and deodorants.
Which chemical found in some pesticides has contributed to ozone depletion through soil fumigation?
Pesticides containing methyl bromide have contributed to ozone depletion through soil fumigation.
Name one product group in which ODSs were widely used as refrigerants.
ODSs, most commonly CFCs, were widely used as refrigerants in cooling systems such as air conditioners and refrigerators.
True or False?
Ozone depletion occurs evenly across the Earth's stratosphere, with no areas of particularly low ozone.
False.
Ozone holes, areas of particularly low stratospheric ozone, are most prominent at the poles.
When do ozone holes typically appear at the poles?
Ozone holes appear every spring at the poles, due to ODSs and seasonal weather patterns.
When ozone formation and destruction rates become unequal, equilibrium is disrupted, allowing more radiation to reach the Earth's surface.
When ozone formation and destruction rates become unequal, equilibrium is disrupted, allowing more UVB radiation to reach the Earth's surface.
What are two effects of increased UVB radiation reaching the Earth's surface due to ozone depletion?
Increased UVB radiation due to ozone depletion increases rates of skin cancer and cataracts, and reduces terrestrial and marine productivity.
Define UNEP.
The United Nations Environment Programme (UNEP) is the UN body that has led efforts to protect the stratospheric ozone layer through research, information-sharing and international agreements.
In which year was the Montreal Protocol on Substances that Deplete the Ozone Layer initiated?
The Montreal Protocol was initiated in 1987.
The Montreal Protocol was initially signed by 24 countries; this total now stands at countries.
The Montreal Protocol was initially signed by 24 countries; this total now stands at 197 countries.
Which 1992 amendment tightened the restrictions of the Montreal Protocol further?
The Copenhagen Amendment (1992) tightened the restrictions of the Montreal Protocol further.
True or False?
Emissions of ozone-depleting substances increased between 1987 and 2010.
False.
Emissions fell from around 1.5 million tonnes in 1987 to around 400,000 tonnes in 2010.
By what year does UNEP hope to end production of all HCFCs?
UNEP hopes to end production of all HCFCs by 2040.
Define a phased reduction.
A phased reduction is a gradual reduction schedule for ozone-depleting substances that allows industries time to adapt and develop alternatives.
What role do national governments play in implementing the Montreal Protocol?
National governments enact national laws and regulations to decrease the consumption and production of ODSs such as CFCs, and promote the transition to ozone-friendly alternatives.
What significant challenge threatens the effectiveness of ozone protection efforts?
The illegal market for ozone-depleting substances is a significant challenge to the effectiveness of ozone protection efforts.
Define a planetary boundary.
A planetary boundary is a threshold that, if crossed, leads to significant environmental change.
What evidence shows that the ozone layer is recovering?
Continuous monitoring shows a decrease in the size of ozone holes over time, indicating that ozone layer recovery is underway.
True or False?
The Montreal Protocol is regarded as the least successful example of international cooperation on an environmental issue.
False.
The Montreal Protocol is regarded as the most successful example yet of international cooperation to resolve a significant environmental issue.
Stratospheric ozone depletion is one of the nine outlined by the planetary boundaries model.
Stratospheric ozone depletion is one of the nine planetary boundaries outlined by the planetary boundaries model.
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