APES Unit 9: Stratospheric Ozone Depletion and Climate Change Effects

What is the role of stratospheric ozone in protecting life on Earth?

Stratospheric ozone absorbs UV-C and much of UV-B radiation, preventing significant tissue damage and DNA mutations, which are essential for life on land.

What are the human health benefits of stratospheric ozone?

It prevents skin cancer and cataracts by blocking harmful UV-B and UV-C radiation.

What is the difference between tropospheric ozone and stratospheric ozone?

Tropospheric ozone is a respiratory irritant and damaging to plant tissue, while stratospheric ozone protects against UV radiation.

When did the formation of the ozone layer occur, and why is it significant?

The ozone layer formed about 600 million years ago, allowing life to evolve from water to land.

How does UV-C radiation contribute to the formation of ozone?

UV-C breaks O2 into free oxygen atoms, which then combine with O2 molecules to form ozone (O3).

What process occurs when ozone absorbs UV-C radiation?

Ozone (O3) can be broken down into O2 and free oxygen atoms by UV-C, which can then recombine to form O2.

What are CFCs and their role in ozone depletion?

CFCs (chlorofluorocarbons) are human-made chemicals that break down ozone in the stratosphere when UV radiation releases chlorine atoms.

How does a single chlorine atom from CFCs affect ozone levels?

One chlorine atom can persist in the atmosphere for 50-100 years and can destroy up to 100,000 ozone molecules.

What natural phenomenon contributes to ozone depletion in Antarctica?

The formation of polar stratospheric clouds (PSCs) during spring melt, which react with chlorine compounds to release free chlorine atoms.

What is the Montreal Protocol, and what was its purpose?

The Montreal Protocol, established in 1987, is a global agreement to phase out the production of CFCs and other ozone-depleting substances.

What are HCFCs and how do they relate to CFCs?

HCFCs (hydrochlorofluorocarbons) are replacements for CFCs that contain hydrogen and are less harmful to ozone but still act as greenhouse gases.

What is the significance of HFCs in the context of ozone depletion?

HFCs (hydrofluorocarbons) are replacements for HCFCs that do not deplete ozone but are still greenhouse gases.

What are HFOs and how do they differ from HFCs?

HFOs (hydrofluoroolefins) are a newer class of chemicals with C-C double bonds that shorten atmospheric lifetime and global warming potential compared to HFCs.

What percentage of incoming solar radiation is reflected back into space?

26% of incoming solar radiation is reflected back into space by clouds and the atmosphere.

What percentage of solar radiation is absorbed by the atmosphere?

19% of incoming solar radiation is absorbed by the atmosphere.

How does UV radiation affect ozone molecules?

UV radiation causes free chlorine atoms to separate from CFCs, which then bond with ozone, converting it into oxygen.

What is the impact of polar stratospheric clouds on ozone depletion?

PSCs facilitate reactions that release chlorine atoms, which then break down ozone molecules.

Why is the replacement of CFCs with HCFCs not a permanent solution?

While HCFCs are less harmful than CFCs, they still deplete ozone and contribute to greenhouse gas effects.

What is the expected timeline for phasing out HCFCs in developing nations?

Developing nations have until 2030 to phase out HCFCs, while developed nations are expected to transition before 2020.

What are the long-term effects of ozone depletion on human health?

Increased rates of skin cancer and cataracts due to higher exposure to UV radiation.

How does the breakdown of ozone by chlorine atoms occur?

Chlorine atoms bond with ozone (O3), converting it into oxygen (O2) and perpetuating the cycle of ozone depletion.

What is the greenhouse effect?

The greenhouse effect is the process by which gases in Earth's atmosphere trap heat from the sun and radiate it back down to Earth.

What would happen to Earth without the greenhouse effect?

Without the greenhouse effect, Earth would be too cold to support life.

How do greenhouse gases contribute to the heating of Earth's climate?

Greenhouse gases absorb infrared radiation released by Earth's surface and radiate it back towards Earth, contributing to warming.

What are the most important greenhouse gases?

The most important greenhouse gases are CO2, methane (CH4), nitrous oxide (N2O), CFCs/HCFCs/HFCs, and water vapor (H2O).

What is the Global Warming Potential (GWP)?

The Global Warming Potential (GWP) measures how much a given molecule of gas can contribute to the warming of the atmosphere over a 100-year period, relative to CO2.

What is the GWP of CO2?

CO2 has a GWP of 1.

What is the GWP of methane (CH4) and its residence time in the atmosphere?

Methane (CH4) has a GWP of 23-84 and remains in the atmosphere for about 12 years.

What is the GWP of nitrous oxide (N2O) and its residence time in the atmosphere?

Nitrous oxide (N2O) has a GWP of 300 and remains in the atmosphere for about 115 years.

What is the GWP of CFCs and their residence time in the atmosphere?

CFCs have a very high GWP and remain in the atmosphere for 50-500 years.

How does thermal expansion contribute to sea level rise?

Thermal expansion occurs when water molecules move slightly further apart when heated, leading to an increase in sea level.

What causes sea level rise besides thermal expansion?

Increased greenhouse gases lead to a warmer climate, resulting in the melting of continental ice sheets and glaciers, which contributes to sea level rise.

What types of ice melting do not contribute to sea level rise?

Melting sea ice, such as North Polar ice, does not cause sea level rise; only land-based ice sheets and glaciers do.

What are some environmental impacts of sea level rise?

Environmental impacts include flooding of coastal ecosystems, loss of species dependent on arctic and tundra ecosystems, and disruption of the thaw-freeze cycle of glaciers.

What are some human impacts of sea level rise?

Human impacts include relocation of coastal populations, saltwater intrusion into groundwater, increased flood frequency, and higher insurance and repair costs.

What are disease vectors?

Disease vectors are living organisms, such as mosquitoes, that can transmit diseases from human to human or animal to human.

How do warmer temperatures affect disease vectors?

Warmer temperatures allow insect-transmitted diseases to spread to areas previously too cold for the vectors.

What is an example of a disease vector and its associated diseases?

An example is Aedes aegypti, which transmits dengue fever, Zika virus, and yellow fever.

What is the projected range expansion of Aedes aegypti?

The projected range of Aedes aegypti is expected to expand further from equators toward poles, putting new human populations at risk.

What is one example of a region where malaria rates may increase by 2050?

Regions in sub-Saharan Africa are likely to see increased malaria rates due to climate change.

What are the Milankovitch Cycles?

Predictable variations in Earth's climate caused by changes in Earth's orbit and axial tilt, occurring over cycles of approximately 100,000 and 40,000 years.

What evidence do scientists use to measure historical climate changes?

1. Foraminifera shells in ocean sediments, which indicate temperature tolerance. 2. Air bubbles in ice cores that contain ancient atmospheric gases. 3. Isotope concentrations (16O vs. 18O) in ancient ice, where higher 18O indicates higher temperatures.

What are the main effects of climate change?

Rising temperatures leading to habitat loss, drought, soil desiccation, heat waves, and increased precipitation in some regions; rising sea levels from ice melt and thermal expansion; and melting permafrost releasing methane and CO2.

How does rising sea level affect coastal communities?

It can lead to property loss, damage, and potential relocation, especially for poorer communities unable to build defenses against flooding.

What happens to barrier islands as sea levels rise?

Barrier islands that protect coastal communities from wind and waves may be lost, increasing vulnerability to storms and erosion.

What is the impact of global warming on atmospheric currents?

It causes the widening and weakening of the Hadley cell, shifting subtropical zones toward the poles and leading to drier climates in certain regions.

How does a destabilized polar jet stream affect weather patterns?

A weakened polar jet stream can lead to extreme cold spells in some areas, like the eastern US, and dry spells in others, like the western US.

What is the relationship between CO2 levels and temperature?

CO2 levels are strongly correlated with temperature, although the exact causality is not fully understood.

What is the significance of melting permafrost?

Melting permafrost releases methane and CO2 from anaerobic decomposition, contributing further to greenhouse gas emissions.

What are the potential risks of global warming reaching 2.0°C?

Increased property loss, damage to coastal communities, loss of barrier islands, and shifts in atmospheric currents leading to extreme weather.

What is the effect of a decreased temperature difference between the equator and poles?

It leads to a weakened and destabilized jet stream, affecting weather patterns and climate stability.

What are the consequences of rising temperatures on ecosystems?

They include habitat and species loss, increased drought, and changes in precipitation patterns.

How do changes in atmospheric currents affect climate?

They can shift dry, desert biomes toward the poles and alter precipitation patterns in mid-latitude regions.

What is the role of thermal expansion in rising sea levels?

Thermal expansion occurs as ocean water warms, contributing to rising sea levels alongside glacial and ice sheet melt.

What is the impact of global climate change on the Hadley cell?

Global warming causes the Hadley cell to widen and weaken, affecting weather patterns and climate zones.

How does climate change contribute to increased precipitation in some regions?

Rising temperatures can lead to more evaporation, which can increase moisture in the atmosphere and result in heavier rainfall in certain areas.

What is the significance of the 100,000-year cycle in Earth's climate history?

It marks the occurrence of global ice ages followed by warmer periods, indicating long-term climate fluctuations.

How does the melting of continental ice sheets affect sea levels?

The melting of continental ice sheets contributes to rising sea levels due to the addition of water to the oceans.

What is the connection between climate change and drought?

Rising temperatures can lead to soil desiccation and increased evaporation, contributing to drought conditions.

What is the role of ancient atmospheric gas in understanding historical climate?

Air bubbles trapped in ice cores provide direct evidence of past atmospheric gas concentrations, including CO2, which is crucial for understanding historical climate changes.

What are the impacts of rising sea levels on marine ecosystems?

Rising sea levels can form new marine habitats by flooding coastlines and alter the range of marine ecosystems.

How does ocean depth affect sunlight penetration in marine ecosystems?

Some areas of the ocean may become too deep to receive sunlight, causing the photic zone to shift upward, further from the ocean floor.

What effect does warmer water have on fish populations?

Warmer water holds less oxygen, leading to declines in fish populations or their migration to cooler waters.

What is thermohaline circulation and how is it affected by climate change?

Thermohaline circulation is a global ocean current that redistributes heat, salt, and nutrients; it may slow or stop due to cold, fresh water buildup from ice melt.

How does ice melt from Greenland impact ocean circulation?

Ice melt contributes cold, fresh water to the North Atlantic, which is less dense than salt water, preventing it from sinking and slowing the Gulf Stream.

What is polar amplification?

Polar amplification refers to the phenomenon where polar regions are warming faster than other regions, particularly the Arctic.

How does melting sea ice contribute to further warming in polar regions?

Melting sea ice exposes more ocean water, which absorbs more sunlight, leading to more ice melting in a positive feedback loop.

What is the impact of melting permafrost on greenhouse gases?

Melting permafrost releases methane and CO2 from anaerobic decomposition, contributing to climate change.

How does air pollution affect polar ice?

Air pollution adds soot and particulate matter to the atmosphere, which can settle on ice, reducing its albedo and causing it to absorb more heat.

What are the consequences of Arctic sea ice loss for marine life?

Arctic sea ice loss results in habitat loss for seals and polar bears, and disrupts the base of the Arctic food web.

How does atmospheric warming lead to ocean warming?

As the atmosphere warms, heat is transferred to the ocean, which absorbs much of the Earth's heat due to water's high specific heat.

What is the relationship between ocean warming and oxygen levels?

Warmer water holds less oxygen, causing respiratory stress or suffocation in marine species.

How can climate change disrupt migratory routes and reproductive timing of marine species?

Changes in temperature can alter migratory routes and mating seasons, disrupting reproductive timing, especially in fish.

What is coral bleaching and how is it related to climate change?

Coral bleaching occurs when corals expel their symbiotic algae (zooxanthellae) due to rising temperatures, leading to stress and vulnerability.

What pollutants can contribute to coral bleaching?

Pollutants from runoff, such as sediment, pesticides, and sunscreen, can force algae from coral reefs.

What is ocean acidification?

Ocean acidification refers to the increase in CO2 in the atmosphere leading to higher levels of CO2 in ocean water, forming carbonic acid.

What happens when carbonic acid dissociates in ocean water?

Carbonic acid dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+), affecting marine organisms.

How does ocean warming affect coral reefs?

Ocean warming can lead to coral bleaching, habitat loss, and increased toxic algae blooms.

What is the role of zooxanthellae in coral reefs?

Zooxanthellae are photosynthetic algae that provide sugars to corals, which in turn supply CO2 and nutrients.

What is the impact of toxic blue-green algae on marine ecosystems?

Toxic blue-green algae can kill marine species, block sunlight, and lead to hypoxia.

How does thermohaline circulation distribute heat in the ocean?

Thermohaline circulation distributes heat absorbed at the ocean surface to deeper waters and other areas of the Earth.

What is the significance of the specific heat of water in climate change?

The high specific heat of water allows oceans to absorb a significant amount of Earth's heat, influencing global temperatures.

What ions do marine organisms use to build their calcium carbonate shells?

Calcium (Ca+) and carbonate (CO32-) ions.

How does increased CO2 contribute to ocean acidification?

Increased CO2 leads to more carbonic acid, which increases H+ ions that bond with carbonate to form bicarbonate (HCO3-), reducing available carbonate ions.

What is the effect of decreased pH on marine shells?

As pH decreases, carbonate ions become less soluble, leading to weaker shells of coral, mollusks, and urchins.

What are the anthropogenic causes of ocean acidification?

Fossil fuel combustion, deforestation, and coal/gas combustion.

What is the relationship between atmospheric CO2 and ocean pH?

There is an inverse relationship; as atmospheric CO2 increases, ocean pH decreases.

How much has ocean pH decreased in the past 150 years?

From 8.2 to 8.1, with projections to decrease to 7.8 by 2100.

What is the significance of the pH scale in relation to ocean acidity?

The pH scale is logarithmic, so a change from 8.2 to 8.1 represents a 30% increase in acidity.

What defines an invasive species?

Species not native to an area, often introduced by humans, with no natural predators and high reproductive rates.

What characteristics make R-selected species more likely to become invasive?

High rates of reproduction, low parental care, and adaptability to diverse habitats.

What impact do zebra mussels have on native ecosystems?

They are aggressive filter feeders that consume algae, which many other species rely on.

How does kudzu vine affect its environment?

It clogs intake pipes, outcompetes native plants for sunlight, and has no herbivore control in the US.

What is the impact of Asian carp on native fish populations?

They outcompete native fish for food and space, decreasing fishery production and value.

What damage does the emerald ash borer cause?

Larvae disrupt tree nutrient transport, killing trees.

How did cane toads become invasive in Australia?

Introduced to control cane beetles, they became invasive due to their large appetite and lack of natural predators.

What are the estimated costs of invasive species to the US economy?

Estimated at $120 billion per year (2005 estimate).

What are some methods for controlling invasive species?

Laws preventing transport, removal of hosts, introduction of natural predators, and physical removal.

What human activities contribute to species becoming endangered?

Poaching, habitat loss, climate change, and competition from invasive species.

Why are niche specialists more prone to endangerment?

They have specific food and habitat needs, making them less tolerant of environmental changes.