Week 2 SI Flashcards
What is the purpose of the Planetary Boundaries model?
It identifies nine critical Earth system processes that regulate the stability of the planet, setting “safe limits” for human activity to prevent severe ecological disruptions.
Define “Planetary Boundaries.”
Planetary Boundaries are thresholds in Earth’s system processes that, if crossed, increase the risk of large-scale, potentially irreversible environmental changes.
When and by whom was the Planetary Boundaries framework introduced?
Introduced in 2009 by Johan Rockström and a team of scientists from the Stockholm Resilience Centre.
List the nine planetary boundaries.
1) Climate Change, 2) Biosphere Integrity, 3) Land-System Change, 4) Freshwater Use, 5) Biogeochemical Flows, 6) Ocean Acidification, 7) Stratospheric Ozone Depletion, 8) Atmospheric Aerosol Loading, 9) Novel Entities.
Explain the “safe operating space” in the Planetary Boundaries model
It is a zone within which human activities can continue without destabilizing critical Earth system processes, thus maintaining a stable and hospitable environment.
What are the “core boundaries” within the Planetary Boundaries framework, and why are they important?
Climate Change and Biosphere Integrity are core boundaries because exceeding them could destabilize the entire Earth system, posing existential risks.
What role does “Climate Change” play as a planetary boundary?
Climate Change involves rising atmospheric CO2 and other greenhouse gases, causing global warming, extreme weather, and sea-level rise, with significant global impacts.
Describe “Biosphere Integrity” and its importance in planetary boundaries
Biosphere Integrity includes biodiversity and ecosystem health, which are essential for resilience and stability in Earth’s systems, supporting life and resources.
What does “Land-System Change” refer to, and why is it a critical boundary?
It refers to human-driven alterations of land, such as deforestation and urbanization, which disrupt habitats, carbon storage, and local climates, threatening biodiversity.
Define “Freshwater Use” as a planetary boundary.
Freshwater Use tracks human consumption of water resources, critical for agriculture, industry, and ecosystems, with excessive use risking water scarcity and ecosystem damage.
Explain the significance of “Biogeochemical Flows” in planetary boundaries.
This boundary involves nitrogen and phosphorus cycles, which are disrupted by human over-fertilization, leading to water pollution, biodiversity loss, and dead zones in water bodies.
What is “Ocean Acidification” and why is it a boundary?
Ocean Acidification is the decreasing pH of seawater due to increased CO2 absorption, harming marine life, particularly organisms with calcium carbonate shells.
Describe “Stratospheric Ozone Depletion” and its relevance as a planetary boundary.
This boundary concerns the depletion of the ozone layer, which protects life from harmful UV radiation; its disruption increases cancer risks and damages ecosystems.
What is “Atmospheric Aerosol Loading,” and what are its effects?
It refers to fine particles in the air from dust, smoke, and pollutants, affecting air quality, human health, and climate by altering heat absorption and cloud formation.
Define “Novel Entities” in the context of planetary boundaries.
Novel Entities include human-made chemicals and synthetic materials like plastics and pesticides, with unknown effects on ecosystems and potential for lasting environmental harm.
How is the “carbon cycle” relevant to planetary boundaries?
The carbon cycle involves the movement of carbon through ecosystems. Human activities, like burning fossil fuels, disrupt this cycle, leading to climate change.
What is “Earth Overshoot Day” and its relation to planetary boundaries?
Earth Overshoot Day marks when humanity’s resource consumption exceeds Earth’s annual regenerative capacity, signaling the crossing of planetary boundaries.
Explain the Doughnut Economics model by Kate Raworth.
Doughnut Economics combines planetary boundaries as environmental ceilings with social foundations, defining a “safe and just space” for humanity.
What does the “social foundation” in Doughnut Economics entail?
The social foundation includes basic human needs like health, education, and equality, ensuring well-being within environmental limits.
How does the “wedding cake” model of SDGs relate to planetary boundaries?
It layers SDGs with ecological goals as the foundation, supporting social and economic goals, implying that environmental stability is crucial for societal and economic health.
Why is biodiversity loss considered a risk within the Planetary Boundaries framework?
Biodiversity loss reduces ecosystem resilience, increasing vulnerability to environmental changes and potentially triggering further boundary transgressions.
What is the threshold for CO2 in the Planetary Boundaries model, and why is it important?
The model sets a safe CO2 level at 350 ppm, with 420 ppm in 2022 indicating a high-risk zone, beyond which climate impacts could be irreversible.
Describe the concept of “safe and just operating space” in Doughnut Economics.
It’s a zone where society meets essential social needs while staying within environmental limits, balancing human well-being with ecological stability.
Why are Climate Change and Biosphere Integrity considered “core” planetary boundaries?
They are central to Earth’s stability; exceeding them could fundamentally alter global ecosystems and climate, making conditions uninhabitable for many species.
