12 Enviro Science Revision - U4 Climate Change

Unit 4 - Climate Change Revision

Learning Objectives

Focus Areas

• Factors affecting climate change

• The enhanced greenhouse effect

• Measuring climate change

• Impacts and consequences of climate change

• Mitigation and adaptation strategies

• Burning of fossil fuels (coal, oil, gas)

• Deforestation

• Agriculture and livestock (methane emissions)

​Anthropogenic Factors

• Volcanic activity

• Solar variability

Natural Factors

Key Drivers of Climate Change

Types of incoming solar radiation

• Ultraviolet (shortwave)

• Infrared (long wave - but higher energy than re-emitted IR)

• Visible (short-long wave)

The albedo effect

• The measure of the reflectivity of a surface.

• High Albedo Surfaces: Ice, snow, and clouds. These surfaces help keep the Earth cooler by reflecting solar energy.

• Low Albedo Surfaces: Darker surfaces such as oceans, forests, and asphalt have low albedo, absorbing more sunlight. This increases warming, contributing to the enhanced greenhouse effect.

• Climate Change Impact:
  As ice melts due to global warming, the Earth’s overall albedo decreases, causing more heat to be absorbed and accelerating the warming process (positive feedback loop).

Multiple Choice

How does a decrease in ice and snow cover due to global warming affect Earth's climate through the albedo effect?

• It increases Earth's albedo, leading to global cooling.

• It decreases Earth's albedo, leading to further warming.

• It has no effect on Earth's climate.

• It increases Earth's albedo, leading to further warming.

Ocean Circulation

• The ocean absorbs large amounts of solar energy, especially in low-latitude regions, and distributes this heat through currents, playing a crucial role in regulating global climate.

• Driven by the Thermohaline Circulation (global conveyor belt), which moves warm water from the equator towards the poles and cold water from the poles back toward the equator.

• Warmer surface water loses heat to the atmosphere, influencing climate and weather patterns.

Ocean Circulation

• Role in the Greenhouse Effect:

  • Oceans store a vast amount of heat and act as a buffer, slowing down the rate of atmospheric warming.

  • Oceans also absorb CO₂, reducing greenhouse gas concentrations but leading to ocean acidification.

Multiple Choice

How does ocean circulation affect the distribution of solar energy and impact global climate?

• Ocean circulation absorbs all solar energy and prevents its transfer to the atmosphere.

• Ocean circulation transfers heat from low-latitude regions to higher latitudes, helping regulate global climate.

• Ocean circulation has no impact on the distribution of solar energy.

• Ocean circulation reflects solar energy back into space, increasing albedo.

Increased concentrations of greenhouse gases due to human activities lead to excessive heat being trapped, resulting in global warming.

​Enhanced Greenhouse Effect

Greenhouse gases (CO₂, methane, water vapour) trap heat in the Earth’s atmosphere, maintaining temperatures suitable for life.

​Natural Greenhouse Effect

The Enhanced Greenhouse Effect

Multiple Choice

Which of the following gases contributes the most to the natural greenhouse effect?

• Water Vapour

• Methane

• Carbon Dioxide

• Nitrous Oxide

Multiple Choice

Which of the following gases contributes the most to the enhanced greenhouse effect?

• Water Vapour

• Methane

• Carbon Dioxide

• Nitrous Oxide

Open Ended

What is the main cause of the enhanced greenhouse effect?

Sample Answer

The enhanced greenhouse effect is primarily caused by increased greenhouse gas concentrations, such as carbon dioxide (CO₂) and methane (CH₄), due to human activities like burning fossil fuels and deforestation.

• Transition to Renewable Energy: Use of solar, wind, hydro, and geothermal to replace fossil fuels.

• Carbon Capture and Storage (CCS): Capturing CO₂ emissions from power plants and storing it underground.

• Reforestation: Planting trees to absorb CO₂ and restore ecosystems.

Actions taken to reduce or prevent the emission of greenhouse gases, with the goal of limiting the severity of climate change.

Mitigation Strategies

Multiple Choice

Which of the following greenhouse gases has the highest global warming potential (GWP)?

• Methane (CH₄)

• Carbon Dioxide (CO₂)

• Nitrous Oxide (N₂O)

• Hydrofluorocarbons (HFCs)

Carbon Sequestration

Short-term (less than 100 yrs)

Carbon sequestration refers to the process of capturing and storing carbon dioxide (CO₂) from the atmosphere, either in land-based ecosystems or oceans, as part of the carbon cycle.

• Land: Carbon is absorbed by plants during photosynthesis and stored in biomass (trees, plants). This carbon is released back into the atmosphere relatively quickly through respiration, decay, or deforestation.

• Water: Carbon is dissolved in surface waters and taken up by marine organisms (e.g., phytoplankton), which can store it for shorter periods in biological systems.

Carbon Sequestration

Long-term (more than 100 yrs)

• Land: Carbon stored in soils or fossil fuels (e.g., coal, oil) through geological processes remains trapped for thousands of years until it is released by natural events or human activities (e.g., combustion of fossil fuels).

• Water: In oceans, carbon can sink to the ocean floor and be stored in deep sediments or as carbonate rocks, locking it away for millennia.

Multiple Choice

Which of the following describes long-term carbon sequestration in the carbon cycle?

• Carbon is stored in plant biomass and released within decades.

• Carbon is dissolved in the surface ocean and released quickly.

• Carbon is trapped in fossil fuels and ocean sediments for thousands of years.

• Carbon is taken up by marine organisms and released within a year.

Altered GHG Concentrations over time

Natural Causes of Greenhouse Gas Variations:

• Seasons: Seasonal changes in photosynthesis and plant activity affect CO₂ levels (lower in growing seasons, higher in winter).

• Years/Centuries: Volcanic eruptions and changes in ocean circulation can lead to fluctuations in atmospheric CO₂ and methane concentrations.

• Millennia: Long-term changes in Earth's orbit (Milankovitch cycles - shape of Earth's orbit and tilt) impact the planet's temperature and greenhouse gas concentrations.

Altered GHG Concentrations over time

Human activities:

• Fossil fuel combustion

• Agriculture and land use changes

• Cement production - The production of cement releases a large amount of CO₂, both from the combustion of fossil fuels to heat limestone and from the chemical process itself (calcination), where calcium carbonate is converted to lime and CO₂ is released.

Multiple Choice

Which of the following is a significant source of CO₂ emissions during cement production?

• The burning of fossil fuels for heating

• The calcination process converting limestone to lime

• Emissions from transporting cement

• Both A and B

• Ice cores (trapped air bubbles give CO₂ levels over millennia)

• Tree rings (indicate past climate conditions)

• Pollen analysis (shows vegetation changes over time)

Historical Measurements

• Temperature records from weather stations

• Sea level rise data from tide gauges

• CO₂ concentrations from atmospheric sensors

​Direct Measurements

Measuring Climate Change

Ice Cores

Each layer contains trapped air bubbles from the time the ice formed, providing a snapshot of the atmosphere's composition.

Ice cores provide climate data extending back hundreds of thousands of years (up to 800,000 years), revealing fluctuations in greenhouse gas concentrations and temperature changes during ice ages and interglacial periods.

Ice Cores

• Gases Measured in Ice Cores:

  • Carbon Dioxide (CO₂): Provides insight into past atmospheric CO₂ levels and correlates with temperature changes.

  • Methane (CH₄): Help identify periods of increased biomass burning and wetland emissions.

  • Nitrous Oxide (N₂O): Indicates agricultural activity and natural nitrogen cycles over time.

  • Oxygen Isotopes (e.g., O-18 and O-16): Ratios of these isotopes are used to infer past temperatures; lighter isotopes evaporate more easily in colder conditions, while heavier isotopes are more prevalent in warmer periods.

Ice Cores

Additional Information from Ice Cores:

• Dust Particles: Indicate volcanic eruptions and wind patterns.

• Sulphate and Nitrate Ions: Help detect past volcanic activity and its impact on global climate.

• Pollutants: Evidence of industrial activity in more recent ice layers, including lead and mercury contamination.

Multiple Choice

Ice core sampling provides valuable data for understanding past climates. Which of the following gases can be measured from air bubbles trapped in ice cores?

• Carbon dioxide (CO₂), methane (CH₄), and oxygen isotopes

• Methane (CH₄), nitrogen dioxide (NO₂), and ozone (O₃)

• Carbon dioxide (CO₂), methane (CH₄), and sulfur dioxide (SO₂)

• Oxygen (O₂), nitrogen (N₂), and fluorinated gases

Multiple Choice

Which method is most likely used to measure temperature data over the last century?

• Tree rings

• Ice cores

• Thermometers placed globally

• Pollen analysis

• Climate models are mathematical representations of Earth’s climate systems.

• Climate models use historical data to simulate past, current, and future climate trends. These models predict how climate will evolve under various emissions scenarios (e.g., “business as usual” or strong mitigation).

• These models simulate interactions between the atmosphere, oceans, ice, and land.

Climate Modelling

• Direct Measurements: Include historical records of temperature, precipitation, CO₂ levels, and ice cover from sources like weather stations, satellites, and ocean buoys.

• Proxy Data: Ice cores, tree rings, and sediment layers provide long-term climate records.

Climate Modelling - Data Inputs

Multiple Choice

Which of the following is NOT a data input commonly used in climate models?

• Historical temperature records

• Tree ring data

• Direct ocean temperature measurements

• Fictional future climate events

• Consistency: When models are accurate, observed and simulated climate data show similar trends (e.g., increasing global temperatures, shrinking ice sheets).

• Discrepancies: Sometimes observed data deviate slightly from simulations due to unforeseen factors (e.g., volcanic eruptions or natural variability), but these differences are generally small in the long term.

Climate Modelling - Use

The Intergovernmental Panel on Climate Change (IPCC) assigns confidence levels to climate projections based on the strength and agreement of evidence:

• Very High Confidence: Strong evidence with high agreement (e.g., global temperature rise).

• High Confidence: Strong evidence but slightly lower agreement (e.g., sea level rise).

• Medium Confidence: Moderate evidence and agreement (e.g., local climate extremes).

• Low Confidence: Limited evidence or mixed agreement.

• Very Low Confidence: Sparse evidence and low agreement.

IPCC Confidence Ratings

Multiple Choice

Which of the following climate projections is likely to have a very high confidence rating according to IPCC guidelines?

• Predicting exact future rainfall in a specific region

• Global temperature rise over the next century

• Estimating the exact speed of polar ice melt

• Predicting short-term weather patterns in local areas

• Increased frequency of extreme weather events (e.g., floods, droughts, heatwaves)

• Food security threats (agriculture impacted by changing growing seasons)

• Displacement of people due to rising sea levels

​Social

• Melting ice caps and glaciers

• Rising sea levels

• Shifts in ecosystems and biodiversity loss

Environmental

Impacts and Consequences of Climate Change

Multiple Choice

Which of the following impacts of climate change directly affects biodiversity?

• Melting glaciers

• Rising sea levels

• Habitat destruction due to changing climate

• Increased energy demand

• Transition to Renewable Energy: Use of solar, wind, hydro, and geothermal to replace fossil fuels.

• Carbon Capture and Storage (CCS): Capturing CO₂ emissions from power plants and storing it underground.

• Reforestation: Planting trees to absorb CO₂ and restore ecosystems.

Actions taken to reduce or prevent the emission of greenhouse gases, with the goal of limiting the severity of climate change.

Mitigation Strategies

Multiple Choice

Which of the following is an example of a mitigation strategy for addressing climate change?

• Building flood barriers along the coast

• Switching from coal to solar power

• Developing drought-resistant crops

• Relocating communities from flood-prone areas

• Building Resilient Infrastructure: Constructing flood barriers, improving drainage systems, and designing heat-resistant buildings.

• Agricultural Adaptations: Developing drought-resistant crops, changing planting seasons.

• Relocation of Vulnerable Communities: Moving people from low-lying coastal areas to safer regions.

Actions taken to adjust to actual or expected climate change and its effects, reducing harm and taking advantage of opportunities.

Adaptation Strategies

Multiple Choice

Which of the following best describes an adaptation strategy to manage the impacts of climate change?

• Carbon capture and storage

• Reforestation

• Developing heat-resistant crops

• Switching to electric vehicles

More practice questions

Open Ended

Explain how climate change can lead to changes in the distribution of plant species globally.

Open Ended

Define climate change mitigation.

Open Ended

List two ways to reduce greenhouse gases in the energy industry.

Multiple Choice

Which of the following is a valid adaptation strategy for climate change in the energy industry?

• Reduction of fossil fuel use

• Use of renewable fuels

• Increase in water usage

• Increased resilience of infrastructure

Multiple Choice

What is the main cause of the enhanced greenhouse effect?

• Natural emissions of CO₂

• Human activities such as burning fossil fuels

• Water vapour naturally present in the atmosphere

• Changes in Earth's orbit

Open Ended

Describe two ways in which climate models help scientists predict future climate variability.

Open Ended

Describe how climate alter the distribution of insect pests. What impacts might this have economically?

Open Ended

Explain how reforestation is an effective strategy to reduce emissions.

Open Ended

List 3 pieces of evidence that indicate climate systems are warming.

Open Ended

Discuss how melting permafrost (ground frozen for 2+ years) contributes to global climate change.

Open Ended

Explain the role of the ocean as a carbon sink and how this process affects global warming.

Open Ended

How does the enhanced greenhouse effect differ from the natural greenhouse effect?

Open Ended

Describe how cement production contributes to increasing CO₂ levels in the atmosphere.

Open Ended

Explain how ocean circulation contributes to regulating global temperatures.

Open Ended

Discuss the role of carbon sequestration in reducing greenhouse gas concentrations. Provide one example of natural and one example of human-made sequestration methods.

Open Ended

Identify and describe one major human activity that contributes to the enhanced greenhouse effect.

Open Ended

How has the global atmospheric concentration of methane (CH₄) changed over the last 100 years, and why is this significant for climate change?