SIO 25 lectures 10-25

Question 1

What are the primary ice sheets on Earth, and why are they significant?

Answer 1

The primary ice sheets are the Greenland and Antarctic ice sheets. They are significant because they store the majority of Earth’s freshwater and influence global sea levels and climate systems.

Question 2

What is the positive feedback mechanism in ice sheet elevation-mass balance?

Answer 2

The positive feedback mechanism involves the reduction of ice sheet elevation due to melting, which exposes lower, warmer layers. This accelerates further melting due to higher temperatures at lower elevations.

Question 3

What makes the West Antarctic Ice Sheet particularly vulnerable?

Answer 3

The West Antarctic Ice Sheet is vulnerable because much of it is grounded below sea level, making it susceptible to melting from warming ocean waters.

Question 4

What is the potential impact of the melting Greenland ice sheet on the Atlantic Meridional Overturning Circulation (AMOC)?

Answer 4

The melting of the Greenland ice sheet releases large amounts of freshwater into the North Atlantic, which can disrupt the AMOC by reducing salinity and density, potentially weakening this critical climate-regulating current.

Question 5

What are the key methods for measuring sea level, and what are their advantages and limitations?

Answer 5

Tide Gauges: Measure sea level relative to land. Advantage: Long historical record. Limitation: Affected by land movement (e.g., subsidence or uplift).
Satellite Altimetry: Measures sea level from space using radar. Advantage: Global coverage. Limitation: Requires advanced calibration and may not capture short-term, localized changes.

Question 6

What factors contribute to global sea level rise?

Answer 6

• Thermal expansion of seawater due to warming.
• Melting of land ice (glaciers and ice sheets).
• Groundwater extraction and runoff into oceans.

Question 7

How does isostatic rebound influence local sea level changes?

Answer 7

Isostatic rebound occurs when land previously compressed under the weight of glaciers rises after the ice melts. This can cause local sea levels to fall even as global sea levels rise.

Question 8

Why is sea level rise a critical issue for coastal populations?

Answer 8

• Increased flooding and storm surges threaten infrastructure and homes.
• Saltwater intrusion can contaminate freshwater supplies.
• Coastal erosion leads to habitat loss and impacts agriculture and tourism.

Question 9

Which areas of the United States are most vulnerable to sea level rise?

Answer 9

• Coastal areas like Florida, Louisiana, and the Eastern Seaboard (e.g., New - - — York, North Carolina).
  Low-lying cities such as Miami and New Orleans.
• Alaska, due to the rapid thawing of permafrost.

Question 10

What strategies can mitigate the risks of sea level rise?

Answer 10

• Building sea walls and flood barriers.
• Restoring natural barriers like wetlands and mangroves.
• Implementing managed retreat (relocating communities).
• Reducing greenhouse gas emissions to slow global warming.
• Enhancing urban planning to make infrastructure more resilient.

Question 11

How does atmospheric CO₂ contribute to ocean acidification?

Answer 11

Atmospheric CO₂ is absorbed by the ocean, where it reacts with water to form carbonic acid, which dissociates into hydrogen ions, lowering the ocean’s pH and making it more acidic.

Question 12

What are the primary impacts of ocean acidification on marine organisms?

Answer 12

Ocean acidification affects marine organisms by reducing the availability of carbonate ions for shell and skeleton formation, weakening structures, and disrupting biological processes like growth, reproduction, and predator detection.

Question 13

What is coral bleaching, and how is it linked to ocean acidification?

Answer 13

Coral bleaching is when corals expel their symbiotic algae due to stress. Ocean acidification weakens coral skeletons and makes them more vulnerable to thermal stress, increasing the likelihood of bleaching.

Question 14

How does ocean acidification affect economically important marine species?

Answer 14

Ocean acidification makes it harder for species like oysters, clams, and certain fish to form shells, slowing growth and increasing mortality. This negatively impacts fisheries and aquaculture industries and disrupts food webs.

Question 15

How does climate change impact global vegetation patterns?

Answer 15

Climate change alters temperature and precipitation patterns, which can shift the range of plant species. Some plants may thrive in new conditions, while others may decline, leading to changes in ecosystems and biodiversity.

Question 16

What role do forests play in mitigating climate change, and how does deforestation contribute to it?

Answer 16

Forests act as carbon sinks, absorbing CO₂ from the atmosphere. Deforestation releases stored carbon back into the atmosphere, contributing to higher greenhouse gas concentrations and accelerating climate change.

Question 17

What are the main challenges for agriculture due to climate change?

Answer 17

Climate change leads to more extreme weather events, such as droughts, floods, and heatwaves, which negatively affect crop yields, disrupt growing seasons, and increase pests and diseases, threatening food security.

Question 18

How does agriculture contribute to global greenhouse gas emissions?

Answer 18

Agriculture contributes to greenhouse gas emissions through livestock digestion (methane), fertilizer use (nitrous oxide), and land-use changes (carbon dioxide). These emissions come from farming practices and deforestation for agricultural expansion.

Question 19

How do livestock contribute to climate change, and what strategies exist to reduce this?

Answer 19

Livestock produce methane during digestion (enteric fermentation), a potent greenhouse gas. Strategies to reduce emissions include improving feed quality, implementing better manure management, and adopting more sustainable farming practices.

Question 20

What is permafrost, and why is its thawing a potential tipping point for climate change?

Answer 20

Permafrost is permanently frozen ground found in polar regions. Thawing releases stored greenhouse gases, such as methane and CO₂, into the atmosphere, potentially accelerating climate change in a feedback loop.

Question 21

What are the Earth’s major reservoirs of carbon?

Answer 21

The major reservoirs of carbon on Earth include the atmosphere, oceans, terrestrial biosphere (plants and soils), and fossil fuels (coal, oil, natural gas).

Question 22

How does the ocean act as a carbon sink, and what is the role of the biological pump?

Answer 22

The ocean absorbs CO₂ from the atmosphere, acting as a carbon sink. The biological pump involves marine organisms, such as plankton, absorbing CO₂ for photosynthesis, and when they die, the carbon is transported to the ocean depths, effectively sequestering it.

Question 24

How does the weathering of silicate rocks remove CO₂ from the atmosphere?

Answer 24

When silicate rocks weather, they chemically react with CO₂ and water to form bicarbonate ions, which are carried by rivers to the ocean. This process reduces atmospheric CO₂ over long periods, contributing to Earth’s carbon balance.

Question 25

What are the turnover times for carbon in various reservoirs, such as the atmosphere, plants, soil, and oceans?

Answer 25

• Atmosphere: Around 3-5 years (carbon stays in the atmosphere before being absorbed or removed).
• Plants: A few months to a decade (carbon in plant biomass is cycled quickly).
• Soil: A few years to thousands of years, depending on the type of carbon and soil conditions.
• Oceans: The surface ocean exchanges carbon with the atmosphere in a few years, but deep ocean carbon can stay for centuries.

Question 26

How have human activities perturbed the carbon cycle?

Answer 26

Human activities, such as burning fossil fuels, deforestation, and agriculture, have added excess CO₂ and methane to the atmosphere, disrupting the natural carbon cycle, leading to higher concentrations of greenhouse gases and contributing to global warming.

Question 28

What are the primary sources of methane emissions, both natural and anthropogenic?

Answer 28

• Natural sources: Wetlands, termites, and oceanic processes.
• Anthropogenic sources: Livestock digestion (enteric fermentation), landfills, fossil fuel extraction, and rice paddies.

Question 29

What is radiative forcing, and how does it affect the Earth’s climate system?

Answer 29

Radiative forcing is the change in energy balance caused by factors like greenhouse gases or aerosols. It affects Earth’s climate system by altering the amount of incoming or outgoing energy, influencing global temperatures. Positive forcing leads to warming, while negative forcing leads to cooling.

Question 30

What role do aerosols play in radiative forcing, and how do they contribute to cooling?

Answer 30

Aerosols can reflect sunlight back into space, creating a negative radiative forcing that leads to cooling. They also influence cloud formation, which can increase cloud reflectivity and further cool the atmosphere.

Question 31

What are the main positive feedback mechanisms in the climate system?

Answer 31

Main positive feedback mechanisms include:

• Water vapor feedback: Warmer temperatures increase evaporation, raising water vapor (a potent greenhouse gas), which further warms the atmosphere.
• Ice-albedo feedback: Melting ice reduces the Earth’s reflectivity, causing more solar radiation to be absorbed, which accelerates warming.
  Cloud feedback: Some clouds trap heat, further warming the planet.

Question 32

How does the ice/snow albedo feedback accelerate warming?

Answer 32

As ice and snow melt due to warming temperatures, the Earth’s surface becomes darker (e.g., exposed ocean or land), causing more solar radiation to be absorbed instead of reflected. This accelerates warming and leads to further ice melt, creating a self-reinforcing cycle.

Question 33

Why is cloud feedback one of the least understood components of climate sensitivity?

Answer 33

Cloud feedback is complex because clouds can both cool (by reflecting sunlight) and warm (by trapping heat). The net effect depends on cloud type, altitude, and other factors. This makes it difficult to predict the overall impact of clouds on future climate change.

Question 34

What is equilibrium climate sensitivity (ECS), and what is its estimated range?

Answer 34

ECS is the long-term temperature change expected from a doubling of atmospheric CO₂ concentration, once the climate system has reached equilibrium. Its estimated range is typically between 1.5°C and 4.5°C, though there is some uncertainty.

Question 35

How do plate tectonics influence the carbon cycle, and why can’t they explain recent warming?

Answer 35

Plate tectonics influence the carbon cycle by controlling volcanic activity, which releases CO₂, and weathering processes that remove CO₂ from the atmosphere. However, plate tectonics operate on timescales of millions of years, so they cannot explain the rapid warming observed in recent decades, which is driven by human activities.

Question 36

What is the Early Anthropogenic Hypothesis, and how does it link agriculture to early climate impacts?

Answer 36

The Early Anthropogenic Hypothesis suggests that human activities, particularly agriculture, began influencing the climate as early as 8,000 years ago. Deforestation and the use of fire for clearing land led to increased greenhouse gas emissions, especially CO₂ and methane, contributing to early climate changes.

Question 37

How does solar variability compare to CO₂ in explaining recent warming trends?

Answer 37

Solar variability, which involves changes in the Sun’s energy output, has not shown significant increases in recent decades. While solar energy affects climate, it is not sufficient to explain the rapid warming observed since the mid-20th century. The primary driver of recent warming is the increase in CO₂ and other greenhouse gases from human activities.

Question 38

What role do carbon isotopes play in identifying human contributions to CO₂ increases?

Answer 38

Carbon isotopes, particularly the ratio of carbon-12 (C-12) to carbon-13 (C-13), can identify the source of CO₂. Fossil fuels have a distinctive lower C-13 content, and the increasing proportion of this type of CO₂ in the atmosphere indicates that human activities, such as burning fossil fuels, are the primary source of recent CO₂ increases.

Question 39

How do atmospheric oxygen levels provide supporting evidence for human-driven climate change?

Answer 39

Atmospheric oxygen levels are closely tied to CO₂ levels. As humans burn fossil fuels, they consume oxygen and release CO₂. The steady decline in atmospheric oxygen levels, alongside rising CO₂ levels, provides evidence of the ongoing combustion of fossil fuels and supports the notion that human activities are driving climate change.

Question 40

How have climate models evolved since the First Assessment Report (FAR) of the IPCC?

Answer 40

Since the First Assessment Report (FAR), climate models have become more sophisticated with higher resolution and better representation of physical processes, such as cloud formation and ocean currents. They now incorporate more detailed data on greenhouse gas emissions, land use, and feedback mechanisms, improving the accuracy of climate projections.

Question 41

What are the key components included in modern climate models?

Answer 41

Modern climate models include components for the atmosphere, oceans, land surface, ice sheets, and biosphere. They simulate energy fluxes, greenhouse gas concentrations, feedbacks (e.g., water vapor, clouds, ice albedo), and interactions between these components to predict future climate behavior.

Question 42

What are Representative Concentration Pathways (RCPs), and how do they guide climate predictions?

Answer 42

RCPs are scenarios that describe different levels of greenhouse gas concentrations in the atmosphere by the year 2100. They are used to model various potential future climate outcomes based on different emission trajectories. RCPs guide climate predictions by providing frameworks for how human activities (e.g., emissions, land use) might evolve.

Question 43

Why is model resolution important, and what are its trade-offs?

Answer 43

Model resolution refers to the level of detail in the spatial and temporal representation of climate processes. Higher resolution models can provide more accurate local predictions, but they are computationally expensive and require more data. Lower resolution models are faster and less resource-intensive but may overlook finer-scale processes, leading to less precision in regional predictions.

Question 44

What is the significance of the discount rate in climate change cost-benefit analysis?

Answer 44

The discount rate reflects how much future costs and benefits are valued compared to present ones. A high discount rate reduces the perceived importance of long-term climate impacts, making it harder to justify immediate action. A lower discount rate gives more weight to future generations, encouraging stronger climate policies.

Question 45

What are the strengths and limitations of cost-benefit analysis in evaluating climate change policies?

Answer 45

• Strengths: Cost-benefit analysis provides a systematic framework to weigh the economic costs of mitigation actions against the long-term benefits of avoided climate damages, helping policymakers prioritize interventions.
• Limitations: It is difficult to accurately quantify long-term climate impacts, especially those related to non-market values (e.g., biodiversity, health), and it may underestimate catastrophic or irreversible risks.

Question 46

What is the social cost of carbon?

Answer 46

The social cost of carbon is the economic cost of the damages caused by emitting one additional ton of CO₂ into the atmosphere, including impacts on health, agriculture, ecosystems, and infrastructure. It is used in policy to assess the cost-effectiveness of reducing emissions.

Question 47

What is the Kaya Identity, and how does it help predict future CO₂ emissions?

Answer 47

The Kaya Identity is an equation that breaks down CO₂ emissions into four factors:
- Population
- GDP per capita
- Energy intensity of GDP
- Carbon intensity of energy
By analyzing these factors, it helps predict how changes in economic growth, energy use, and technology will influence future CO₂ emissions.

Question 48

What trends in energy efficiency have been observed, and how do they impact CO₂ emissions?

Answer 48

Energy efficiency improvements, such as advances in technology and renewable energy, have led to reduced energy consumption per unit of economic output. However, these efficiency gains can be offset by increases in energy demand, making overall reductions in CO₂ emissions dependent on broader changes in energy sources and consumption patterns.

Question 49

What are the implications of climate change for developing versus developed countries?

Answer 49

• Developed countries: Typically more resilient to climate impacts due to better infrastructure, but they are also historically responsible for a larger share of emissions and face pressure to lead in mitigation efforts.
• Developing countries: More vulnerable to the impacts of climate change, such as extreme weather and food insecurity, but they often lack the resources to adapt or mitigate. They also seek support from developed countries for financing and technology transfer.

Question 50

What adaptation strategies can mitigate the impacts of future heat waves?

Answer 50

Adaptation strategies include:

Improving urban infrastructure, such as increasing green spaces and using reflective materials in buildings to reduce heat absorption.
Expanding access to cooling centers and air conditioning, especially for vulnerable populations.
Implementing early warning systems for heat waves to allow communities to prepare.
Planting trees and creating urban forests to provide shade and lower temperatures.

Question 51

Q: Give an example of how climate change exacerbates displacement and migration.

Answer 51

Climate change can worsen displacement through extreme weather events, such as hurricanes, floods, and droughts, that destroy homes and livelihoods. For example, in areas like the Sahel in Africa, changing rainfall patterns and droughts lead to food and water scarcity, forcing people to migrate to more stable regions in search of resources and better living conditions.

Question 52

What is the relationship between climate change and the spread of disease-carrying mosquitoes?

Answer 52

Climate change affects the distribution of disease-carrying mosquitoes by altering temperature and precipitation patterns. Warmer temperatures and changing rainfall create favorable conditions for mosquitoes to thrive in new regions, potentially expanding the reach of diseases like malaria, dengue, and Zika to areas where they were previously uncommon.

Question 53

How do photovoltaics and concentrating solar power differ in harnessing solar energy?

Answer 53

• Photovoltaics (PV): Use semiconductor materials to convert sunlight directly into electricity through the photovoltaic effect.
• Concentrating Solar Power (CSP): Uses mirrors or lenses to concentrate sunlight onto a small area, typically to heat a fluid that drives a steam turbine to generate electricity.

Question 54

Compare the advantages and challenges of onshore and offshore wind power.

Answer 54

• Onshore wind power:
  Advantages: Lower costs, easier installation, and maintenance.
  Challenges: Limited by land availability, wind consistency, and local opposition.
• Offshore wind power:
  Advantages: Stronger and more consistent winds, less land use conflict.
  Challenges: Higher installation and maintenance costs, technical challenges in deep water.

Question 55

What role does hydropower play in global energy production, and what are its benefits and limitations?

Answer 55

• Role: Hydropower is one of the largest sources of renewable energy worldwide, providing about 16% of global electricity.
• Benefits: Clean, reliable, and capable of producing large amounts of electricity; can also store energy (pumped storage).
• Limitations: Environmental impact on aquatic ecosystems, displacement of communities, and dependence on water availability.

Question 56

How does geothermal energy contribute to renewable energy, and what are its benefits and limitations?

Answer 56

• Contribution: Geothermal energy harnesses heat from the Earth’s core to generate electricity or provide direct heating.
• Benefits: Reliable, continuous, and low emissions.
• Limitations: Geographically limited to areas with high geothermal activity (e.g., volcanic regions), potential land use conflicts, and high upfront costs.

Question 57

Q: What are the key benefits and challenges of nuclear power in decarbonization efforts?

Answer 57

• Benefits: Low-carbon energy source, capable of providing consistent, baseload power without greenhouse gas emissions.
• Challenges: High capital costs, long construction times, safety concerns (e.g., accidents, waste disposal), and political and public resistance.

Question 58

How does Carbon Capture and Storage (CCS) technology work, and what are its current limitations?

Answer 58

• How it works: CCS captures CO₂ emissions from power plants and industrial sources, transports it, and stores it underground in geological formations.
• Limitations: High costs, lack of infrastructure, concerns about long-term storage integrity, and limited current deployment.

Question 59

What is Bioenergy with Carbon Capture and Storage (BECCS), and what are its potential benefits and risks?

Answer 59

• BECCS: Combines bioenergy (energy from biomass) with CCS to capture and store CO₂ emitted during biomass combustion, theoretically leading to negative emissions.
• Benefits: Can contribute to negative emissions, mitigate climate change, and provide renewable energy.
• Risks: Land-use competition for biomass production, high costs, and potential environmental impacts from large-scale bioenergy farming.

Question 60

What are the advantages and challenges of afforestation and reforestation as CDR methods?

Answer 60

• Advantages:
  Absorb CO₂ from the atmosphere, enhancing carbon sequestration.
  Can improve biodiversity and soil health.
  Relatively low cost compared to other carbon removal methods.
• Challenges:
  Requires large areas of land, potentially competing with agriculture and natural ecosystems.
  Long-term sustainability is uncertain, especially with the risk of forest fires, pests, and diseases.
  Potential displacement of communities or indigenous peoples.

Question 61

What is direct air carbon capture (DAC), and what are the primary barriers to its deployment?

Answer 61

• What it is: DAC technology captures CO₂ directly from the atmosphere and stores it, often underground.
• Barriers:
  > High energy and operational costs, especially for large-scale deployment.
  > Lack of infrastructure for storage and transport of captured CO₂.
  > Technological scalability is uncertain.

Question 62

What is enhanced terrestrial weathering, and what are its potential benefits and limitations?

Answer 62

• What it is: Enhanced terrestrial weathering involves spreading minerals (like olivine) on land to speed up natural chemical reactions that absorb CO₂ from the atmosphere.
• Benefits:
  > Can capture CO₂ at scale and is a natural, long-term process.
  > Could help improve soil health.
• Limitations:
  > Requires large amounts of minerals and land.
  > Potential environmental impacts, such as disruption to ecosystems and water quality.

Question 63

How does stratospheric aerosol injection aim to manage solar radiation, and what risks does it pose?

Answer 63

• How it works: Stratospheric aerosol injection involves releasing reflective particles (e.g., sulfur dioxide) into the stratosphere to reflect some sunlight away from Earth, cooling the planet.
• Risks:
  > Could alter weather patterns, causing regional disruptions.
  > Potential impacts on ozone depletion.
  > Does not address the root cause (CO₂ emissions) and could have unpredictable side effects.

Question 64

What is marine cloud brightening and how does it contribute to radiation management?

Answer 64

• What it is: Marine cloud brightening involves spraying seawater droplets into low-lying clouds to increase their reflectivity, which would reflect more sunlight away from Earth.
• Contribution: This technique could temporarily cool the planet by increasing the albedo (reflectivity) of clouds, helping to reduce solar radiation reaching the Earth’s surface.

Question 65

What is cirrus cloud thinning, and how does it differ from other radiation management techniques?

Answer 65

• What it is: Cirrus cloud thinning involves reducing the thickness of high-altitude cirrus clouds, which trap heat in the atmosphere.
• Difference: Unlike other methods (such as aerosol injection), cirrus cloud thinning aims to reduce the warming effect of clouds rather than reflect sunlight. It is a form of “solar radiation management” that focuses on reducing heat retention rather than blocking incoming sunlight.

Question 66

What are the barriers to using space-based mirrors for radiation management?

Answer 66

• Barriers:
  > Extremely high cost of building and launching large-scale mirrors into space.
  > Technical challenges in deploying and maintaining mirrors in space.
  > Uncertainty about the long-term effectiveness and potential unintended consequences on global climate systems.

Question 67

What is an externality, and how does it relate to greenhouse gas emissions?

Answer 67

• What it is: An externality is a side effect or consequence of an economic activity that affects other parties who did not choose to be involved in that activity.
• Relation to greenhouse gas emissions: Greenhouse gas emissions are a negative externality because they cause environmental damage (e.g., climate change) that is not reflected in the cost of producing goods or services, impacting society and future generations.

Question 68

Q: What is market failure, and why does it justify government intervention in addressing climate change?

Answer 68

• What it is: Market failure occurs when the market fails to allocate resources efficiently, leading to suboptimal outcomes, such as environmental degradation.
• Justification for government intervention: Climate change represents a market failure because the costs of emissions (e.g., rising global temperatures, extreme weather) are not accounted for in market prices, leading to over-emission. Government intervention is necessary to correct this failure and promote sustainable practices through policies like carbon pricing.

Question 69

How does a carbon tax work, and what are its key advantages?

Answer 69

• How it works: A carbon tax imposes a fee on each ton of CO₂ emitted by businesses and individuals, effectively raising the cost of carbon-intensive activities.
• Advantages:
  > Provides a clear economic signal to reduce emissions.
  > Encourages innovation in cleaner technologies and energy efficiency.
  > Generates government revenue, which can be reinvested into green initiatives or returned to citizens.

Question 70

What is a cap-and-trade system, and how does it differ from a carbon tax?

Answer 70

• Cap-and-trade: Sets a cap on the total amount of greenhouse gases that can be emitted and allows businesses to buy and sell emissions allowances (credits) within that limit.
• Difference from carbon tax:
  > A cap-and-trade system establishes a firm emissions limit (cap), with market-driven pricing for allowances.
  > A carbon tax directly sets the price of carbon but does not control the total emissions, giving businesses flexibility in how they reduce emissions.

Question 71

What are the co-benefits (besides reducing emissions) of carbon pricing strategies?

Answer 71

• Co-benefits:
  > Improved public health: Reduced air pollution from carbon-intensive activities leads to lower rates of respiratory diseases and other health issues.
  > Economic innovation: Encourages investment in clean energy technologies, driving economic growth in new sectors.
  > Job creation: Renewable energy industries and green technologies can create new employment opportunities.

Question 72

What lessons can be learned from successful climate policies worldwide?

Answer 72

Lessons:
- Clear, long-term goals: Policies with clear and ambitious targets
- Flexibility and market mechanisms: Successful policies often combine regulations with market-based tools (e.g., cap-and-trade systems, carbon taxes) to reduce emissions cost-effectively.
- Public and private sector collaboration: Successful climate policies engage both government and industry to foster innovation and accelerate the transition to low-carbon economies.

Question 73

What is the Keeling Curve, and how did it revolutionize the study of atmospheric CO₂?

Answer 73

• What it is: The Keeling Curve is a graph that shows the concentration of CO₂ in the Earth’s atmosphere, measured at the Mauna Loa Observatory in Hawaii since 1958.
• Revolutionized the study of atmospheric CO₂: It provided the first clear evidence of the rising levels of CO₂ due to human activity, showing seasonal fluctuations as well as the long-term upward trend, and became a key piece of evidence linking fossil fuel use to global warming.

Question 74

What problem did the Montreal Protocol address, and what made it a success?

Answer 74

• Problem it addressed: The Montreal Protocol was designed to phase out the use of ozone-depleting substances (CFCs and other chemicals) that were contributing to the depletion of the ozone layer.
• Success factors:
  > It had strong international cooperation, with nearly every country signing the agreement.
  > It was based on scientific consensus and included clear, enforceable targets.
  > The protocol led to a significant reduction in ozone-depleting chemicals and the eventual recovery of the ozone layer.

Question 75

Why did the Kyoto Protocol fail to significantly reduce global greenhouse gas emissions?

Answer 75

• Reasons for failure:
  > The protocol lacked enforcement mechanisms, so countries could fail to meet targets without significant consequences.
  > Major emitters like the U.S. and developing countries like China were either not bound by the same targets or withdrew from the agreement.
  > There was insufficient flexibility for countries to meet their targets through cost-effective means, leading to inefficiencies in emission reductions.

Question 76

What distinguishes the Paris Agreement from previous climate treaties?

Answer 76

• Distinguishing features:
  The Paris Agreement is based on voluntary commitments, with each country setting its own nationally determined contributions (NDCs) for emission reductions.
• It has a more flexible, bottom-up approach compared to previous top-down agreements like the Kyoto Protocol.
• The agreement emphasizes long-term global goals (keeping warming below 2°C, with efforts to limit it to 1.5°C) and includes mechanisms for increasing ambition over time, with regular review and reporting.

Question 77

What are the main barriers to the enactment of effective climate policy and progress toward eliminating greenhouse gas emissions?

Answer 77

• Barriers:
  > Political resistance: Lack of political will due to vested interests, short-term economic concerns, or partisan divides.
  > Economic challenges: Transitioning away from fossil fuels can be expensive, and there are concerns about job losses in traditional energy sectors.
  > Global coordination: Differing priorities and capabilities among countries, especially between developed and developing nations.
  > Technological and financial gaps: Insufficient access to renewable energy technologies and the financial resources needed to implement them, especially in developing countries.

Question 78

What is the Nordhaus “Climate Club” approach, and what problem is it trying to solve?

Answer 78

• What it is: The “Climate Club” is an idea proposed by economist William Nordhaus, where countries commit to stringent climate policies and join a cooperative agreement. Countries in the club would impose carbon tariffs on those outside the club to incentivize global participation in climate action.
• Problem it addresses: It seeks to solve the issue of free-riding, where some countries benefit from the climate efforts of others without making their own commitments, thus undermining global climate cooperation.

Question 79

What is the concept of overshoot, and why is it problematic?

Answer 79

• What it is: “Overshoot” refers to a scenario where global emissions exceed the sustainable levels needed to keep global warming within safe limits (e.g., 1.5°C or 2°C) before eventually coming down through negative emissions or other mitigation efforts.
• Why it’s problematic:
  > It could lead to irreversible damage to ecosystems, biodiversity, and human systems.
  > The required scale of negative emissions needed to return to safe levels is highly uncertain, and relying on future technologies that are not yet proven could be risky.

Question 80

What is an example of a stranded asset, and why are stranded assets important to meeting climate goals?

Answer 80

• Example: Stranded assets are investments or resources (e.g., fossil fuel reserves, coal plants, oil rigs) that lose their value due to changes in market conditions, regulations, or environmental factors, such as the shift to renewable energy.
• Importance: Stranded assets are a challenge to meeting climate goals because they represent investments in carbon-intensive infrastructure that may become obsolete, creating financial risks and potentially slowing the transition to a low-carbon economy.

Question 81

How are corporations thought to be responsible for climate change and what are some of the means that are being put forward to hold corporations accountable?

Answer 81

Corporate responsibility: Corporations, especially in fossil fuel, manufacturing, and agriculture sectors, are major contributors to greenhouse gas emissions due to their operations, supply chains, and product consumption.
Means of holding them accountable:
Carbon pricing: Imposing taxes or tariffs on emissions to incentivize corporations to reduce their carbon footprint.
Regulations and policies: Governments can set emissions reduction targets, require emissions disclosures, and mandate sustainable practices.
Shareholder activism: Investors are pressuring corporations to adopt sustainable practices and disclose climate-related risks.
Public pressure and consumer choices: Advocacy and consumer demand for environmentally responsible companies are driving corporate changes.