8.6 Review (Slides and questions)

Review

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​Review

Earth’s Energy Balance and Temperature Regulation

Many people mistakenly believe that all greenhouse gases are harmful, when, in reality, they are essential for maintaining Earth's temperature.

The problem arises when human activities increase their concentration, disrupting the natural balance.

Multiple Choice

Which of the following claims is supported by the data in the Global Land-Ocean Temperature Index graph?

• The levels of carbon dioxide in the atmosphere have risen over the past century.

• Average temperatures have risen over the past century.

• There is not overall trend in global temperature data over the last century.

• The levels of carbon dioxide in the air affect the temperature of our plant.

Solar radiation

Solar radiation is the energy emitted by the Sun in the form of electromagnetic waves, including visible light, ultraviolet light, and infrared radiation. It's important to remember:

oNot all solar radiation reaches Earth's surface; some is blocked by the atmosphere, clouds, and other factors.

oSome of the incoming solar radiation is reflected back into space, rather than being absorbed by Earth’s surface.

oWhen a surface absorbs solar radiation, it is converted into thermal energy (heat).

albedo

•The proportion of solar radiation that is reflected by a given surface is called the albedo.

oThe higher albedo a surface has, the lighter it will appear.

oa low albedo results in darker color since most of the light is absorbed rather than reflected.

The way surfaces interact with light plays a crucial role in their appearance and temperature.

•White surfaces appear white because they reflect all or nearly all of the light that strikes them

•black surfaces absorb all or nearly all of the light that hits them.

Multiple Choice

Which of the following surfaces has the HIGHER albedo?

• road

• ice

Multiple Choice

Terrance wore a black T-shirt to a concert in the park. His friend, Brian, wore a yellow shirt. Terrance keeps complaining that it is too hot, but Brian insists it is the perfect temperature.

Which of the following is a reasonable explanation for what is happening?

• Brian's shirt has high albedo, so it is absorbing light creating more heat.

• Terrance's shirt has high albedo, so it is reflecting light.

• Brian's shirt has low albedo, so it is reflecting the light.

• Terrance's shirt has low albedo, so it is absorbing the light creating more heat.

• Solar radiation: Energy emitted from the sun, primarily in the form of visible light, that reaches the Earth's atmosphere; this is the incoming radiation from the sun. 

• Terrestrial radiation: Infrared radiation emitted from the Earth's surface back into space, considered "longwave" radiation due to the Earth's cooler temperature compared to the sun. 

• Back radiation: A portion of the Earth's terrestrial radiation that is absorbed by greenhouse gases in the atmosphere and then re-radiated back towards the Earth's surface, contributing to the greenhouse effect. 

Without an atmosphere:

• Solar radiation:

  The same amount of solar radiation would reach the Earth's surface, but with no atmosphere to absorb it, the surface would directly radiate most of this energy back into space. 

• Terrestrial radiation:

  Since the Earth's surface would be much colder without an atmosphere to trap heat, the amount of terrestrial radiation emitted would be significantly less. Essentially, there would be minimal "back radiation" as no atmospheric gases would be present to re-radiate the energy back to the surface. 

With an atmosphere:

• Solar radiation:

  When solar radiation reaches the Earth, some is reflected back into space by clouds and the surface, while the rest is absorbed by the Earth's surface and atmosphere. 

• Terrestrial radiation:

  As the Earth's surface warms from absorbed solar radiation, it emits infrared radiation (terrestrial radiation). Greenhouse gases in the atmosphere trap a significant portion of this outgoing radiation, causing "back radiation" that warms the surface further. 

​Key takeaway
The presence of an atmosphere, particularly greenhouse gases, significantly impacts the Earth's energy balance by trapping a portion of the outgoing terrestrial radiation through back radiation, leading to a warmer surface temperature. 

Multiple Choice

Which of the following is a key difference between solar and terrestrial radiation?

• Solar radiation is emitted by the Earth, while terrestrial radiation is emitted by the Sun.

• Solar radiation is absorbed by the Earth's surface, while terrestrial radiation is emitted from the surface back to the atmosphere.

• Solar radiation is visible light, and terrestrial radiation is only in the infrared range.

• Solar radiation does not contribute to the greenhouse effect, while terrestrial radiation does.

Multiple Choice

What term best describes radiation that is returned to Earth's surface by molecules in the atmosphere?

• Global warming

• Back radiation

• Intercepted solar radiation

• Through window

Multiple Choice

Which of the following statements best describes Earth's temperature if it did not have an atmosphere?

• Earth's temperature would remain the same because the Sun provides a constant amount of energy.

• Earth's surface would be slightly warmer because there would be less air to absorb heat.

• Earth's surface would be much colder because there would be no greenhouse gases to trap heat.

• Earth's surface would be much warmer because there would be no clouds to block solar radiation.

Multiple Choice

What is the greenhouse effect?

• A natural process where greenhouse gases trap heat in Earth’s atmosphere, keeping the planet warm.

• The depletion of the ozone layer, allowing more solar radiation to reach Earth.

• The reflection of sunlight by clouds, reducing Earth’s temperature.

• The increase in plant growth due to higher levels of carbon dioxide.

Multiple Choice

what is the primary role of greenhouse gases in the Earth's atmosphere?

• reflecting sunlight back into space

• trapping heat and maintaining Earth's temperature

• producing oxygen for respiration

• increasing ocean salinity

Greenhouse Gases

• Carbon dioxide (CO2): Released mainly from burning fossil fuels, volcanic eruptions, and respiration, it is the most significant anthropogenic greenhouse gas.

• Methane (CH4): Produced by natural decomposition, livestock digestion, and human activities like fossil fuel extraction, it is a potent greenhouse gas.

• Nitrous oxide (N2O): Emitted from agricultural practices, burning biomass, and fossil fuels, it contributes to both global warming and ozone depletion.

• Water vapor (H2O): The most abundant greenhouse gas, its concentration is controlled by temperature and acts as a feedback mechanism amplifying warming.

​Natural sources of greenhouse gases

- Respiration: Plants, animals, and microorganisms release carbon dioxide (CO₂) into the atmosphere as a byproduct of energy production.

- Bacterial activity in wetlands and livestock digestion: Microorganisms in wetlands and ruminants produce methane (CH₄) during anaerobic digestion.

- Biological decay: Decomposition of organic matter by bacteria and fungi releases CO₂ and methane.

- Oceanic processes: Oceans release CO₂ and methane through processes like respiration by marine organisms and the outgassing of dissolved gases.

- Wildfires and volcanic activity: Wildfires release CO₂ and other gases, while volcanic eruptions emit gases such as CO₂, methane and sulfur dioxide.

Multiple Select

Which of the following is a greenhouse gas? SELECT ALL THAT APPLY

• carbon dioxide

• nitrous oxide

• methane

• water vapor

Multiple Choice

Which greenhouse gas is the most abundant in the atmosphere?

• carbon dioxide

• water vapor

• methane

• nitrous oxide

Match

Match the following

• Respiration, volcanic eruptions

• Wetlands, livestock digestion, biological decay

• Soil processes, oceans, natural vegetation

• Evaporation, transpiration

Carbon Dioxide (CO₂)

Methane (CH₄)

Nitrous Oxide (N₂O)

Water Vapor (H₂O)

• Carbon Dioxide (CO₂)

• Methane (CH₄)

• Nitrous Oxide (N₂O)

• Water Vapor (H₂O)

Natural Climate Change refers to long-term shifts in Earth's climate caused by natural factors rather than human activities. These variations occur over decades to millions of years due to the following key processes:

• Milankovitch Cycles (Earth’s Tilt and Orbit): Changes in Earth’s orbital shape (eccentricity), axial tilt (obliquity), and wobble (precession) alter the distribution and intensity of sunlight over thousands of years, driving glacial and interglacial periods.

• Solar Variation: The Sun’s energy output fluctuates due to sunspot cycles and solar radiation changes, influencing Earth's climate by increasing or decreasing global temperatures.

• Changes in Ocean Currents: Shifts in major oceanic currents, such as the Atlantic Meridional Overturning Circulation (AMOC) and phenomena like El Niño and La Niña, redistribute heat and moisture, affecting global climate patterns.

• Volcanic Eruptions: Large eruptions release greenhouse gases like CO₂, contributing to long-term warming, while sulfur-rich aerosols temporarily cool the planet by blocking sunlight.

• Meteorite Impact: Large asteroid or comet impacts can inject dust and aerosols into the atmosphere, reducing sunlight and triggering cooling events, potentially leading to mass extinctions.

• Tectonic Plate Movement and Mountain Formation: Shifting continents alter ocean currents and atmospheric circulation, while mountain formation affects wind patterns and long-term climate trends by influencing precipitation and temperature distributions.

These natural processes have historically driven climate fluctuations, including ice ages and warm periods, shaping Earth's environmental history.

Multiple Choice

Which of the following is NOT a natural cause of climate change?

• Changes in Earth’s orbit and tilt (Milankovitch Cycles)

• Volcanic eruptions releasing greenhouse gases and aerosols

• Industrial emissions from burning fossil fuels

• Variations in solar radiation affecting Earth's temperature

Multiple Choice

Which natural event can cause short-term cooling of Earth's climate by blocking sunlight with dust and aerosols?

• Changes in ocean currents

• Volcanic eruptions

• Tectonic plate movement

• Milankovitch Cycles

Multiple Choice

Which natural process is responsible for the movement of continents, altering ocean currents and climate over millions of years?

• Solar variation

• Milankovitch Cycles

• Tectonic plate movement

• Volcanic eruptions

Multiple Choice

In the "Carbon Dioxide and Global Temperature Comparison" graph, what relationship can be observed between carbon dioxide levels in the atmosphere and temperature?

• As carbon dioxide levels increase, global temperatures decrease.

• There is no noticeable relationship between carbon dioxide levels and global temperature.

• As carbon dioxide levels increase, global temperatures also rise.

• Global temperatures and carbon dioxide levels are inversely related.

Anthropogenic sources of greenhouse gases

Burning of Fossil Fuels (Coal, Oil, Natural Gas)

Combustion of fossil fuels for electricity, transportation, and industry releases CO₂ into the atmosphere, which traps heat and contributes to global warming.

Deforestation

Deforestation reduces the number of trees that absorb CO₂, directly increasing atmospheric carbon levels and disrupting the natural carbon cycle.

Agriculture and Soil Tillage

Livestock farming (especially cattle) produces methane (CH₄) from digestion (enteric fermentation), while soil tillage releases CO₂ from the soil and increases the release of nitrous oxide (N₂O) from fertilizers, both potent greenhouse gases that contribute to climate change.

Land Degradation

Degraded lands, often resulting from overgrazing, deforestation, or poor farming practices, lose their ability to absorb CO₂, leading to higher carbon emissions and less effective carbon sequestration.

Waste Management

Landfills generate methane (CH₄) as organic waste decomposes anaerobically, contributing significantly to greenhouse gas emissions.

Industrial Processes

Manufacturing industries release various greenhouse gases, including CO₂, methane, and hydrofluorocarbons (HFCs), particularly during cement production, chemical manufacturing, and the use of refrigeration systems.

These human activities significantly increase greenhouse gas concentrations in the atmosphere, enhancing the greenhouse effect and leading to rising global temperatures and climate change.

Multiple Choice

How does burning fossil fuels contribute to climate change?

• It absorbs CO₂ from the atmosphere.

• It releases CO₂ into the atmosphere

• It reduces methane emissions.

• It increases oxygen levels in the atmosphere.

Multiple Choice

How does deforestation contribute to climate change?

• It increases oxygen production.

• It removes trees that absorb CO₂, increasing atmospheric carbon levels.

• It enhances soil fertility.

• It reduces methane emissions.

Multiple Choice

How do human-made greenhouse gas emissions contribute to climate change?

• By releasing greenhouse gases that cool the Earth's surface.

• By intensifying the natural greenhouse effect, trapping heat and warming the Earth's surface.

• By reducing the natural greenhouse effect, leading to cooling temperatures.

• By preventing heat from reaching the Earth's surface.

​Climate change refers to long-term changes in the average weather patterns on Earth, including shifts in temperature, precipitation, and other atmospheric conditions, primarily driven by human activities such as the burning of fossil fuels, deforestation, and industrial processes, which increase greenhouse gas concentrations in the atmosphere.

Evidence of Climate Change:

Melting Glaciers: Glaciers worldwide are retreating as global temperatures rise, contributing to higher sea levels and altering water availability in some regions.

Sea Level Rising: Rising global temperatures cause polar ice to melt and seawater to expand, leading to a steady increase in sea levels, threatening coastal communities and ecosystems.

Ocean Acidification: Increased CO₂ in the atmosphere is absorbed by oceans, lowering pH levels, which harms marine life, particularly coral reefs and shell-forming organisms.

Evidence of Climate Change:

Coral Bleaching: Rising ocean temperatures cause corals to expel the symbiotic algae they depend on, leading to bleaching and weakened coral reefs, which are crucial for marine biodiversity.

Adaptations: Species are evolving or shifting their ranges in response to changing climates, such as migrating to cooler areas or developing new behaviors to survive altered conditions.

Phenology: Changes in the timing of natural events, such as earlier blooming of flowers or migrations, reflect shifts in climate patterns, impacting ecosystems and food chains.

Multiple Choice

Why are sea levels and the presence of ice in polar regions studied in order to determine the impacts of climate change?

• Decreased temperatures due to climate change causes ice to melt in polar regions, which causes the sea level to rise.

• Increased temperatures due to climate change cause ice to melt in polar regions, which causes the sea level to rise.

• Decreased temperatures due to climate change cause ice to form in polar regions, which causes the sea level to decline.

• Increased temperatures due to climate change cause ice to melt in polar regions, which causes the sea level to decline.

Multiple Choice

How does increased CO₂ affect the oceans?

• It increases ocean temperatures

• It lowers ocean pH, leading to ocean acidification

• It helps coral reefs grow

• It causes glaciers to grow

Multiple Choice

What causes coral bleaching?

• Increased algae growth in cooler waters

• Warmer ocean temperatures causing corals to expel algae

• Increased rainfall causing freshwater influx

• Reduced oceanic CO₂ levels

Multiple Choice

How are species adapting to climate change?

• Species are migrating to cooler regions or evolving new behaviors

• Species are remaining in their current habitats without change

• Species are becoming extinct due to higher temperatures

• Species are returning to warmer climates

Multiple Choice

What does phenology refer to in the context of climate change?

• The physical movement of species in response to climate shifts

• The timing of natural events, like blooming or migrations, changing due to climate shifts

• The formation of glaciers as a result of lower temperatures

• The increase in ocean temperatures and ice cap growth

Poll

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