Sustainability Models

1. These models are useful for decision-making, policy planning, and assessing sustainability, but they also have limitations due to their simplifications.
2. They help policymakers make informed environmental and economic decisions.
3. They raise awareness of sustainability issues for businesses, governments, and individuals.
4. They allow comparisons between different regions, industries, or policies.

The UN Sustainable Development Goals (SDGs)

1. Adopted in 2015 by all UN member states as part of the 2030 Agenda for Sustainable Development.
2. There are 17 SDGs, each linked to specific targets and indicators.
3. They aim to address global challenges, including poverty, inequality, climate change, environmental degradation, peace and justice.

Core Themes of the SDGs

1. Environmental Sustainability: Protect biodiversity, reduce pollution, reduce greenhouse gas emissions, conserve water and forests.
2. Social Sustainability: Human rights, access to education, healthcare, equality, community empowerment.
3. Economic Sustainability: Fair economic opportunities, decent work, responsible production and consumption, poverty reduction.

Three Pillars of Sustainability

Key SDGs Linked Directly to Environmental Sustainability

1. Goal 6: Clean Water and Sanitation: Ensures sustainable water management and access to safe drinking water.
2. Goal 7: Affordable and Clean Energy: Expands renewable energy and energy efficiency.
3. Goal 12: Responsible Consumption and Production: Reduces waste and encourages sustainable resource management.
4. Goal 13: Climate Action: Strengthens global responses to climate change.
5. Goal 14: Life Below Water: Protects marine ecosystems.
6. Goal 15: Life on Land: Conserves forests, biodiversity, and land resources.

How SDGs Support Sustainability

1. Encourage renewable energy adoption to reduce carbon emissions.
2. Require responsible industrial practices to minimize pollution.
3. Promote equitable access to natural resources (links to environmental justice).
4. Protect biodiversity to maintain ecosystem services.
5. Strengthen global cooperation, which is necessary for issues like climate change that do not respect national borders.

Limitations of the SDGs

1. Implementation depends on political will and funding, which vary by country.
2. Progress can be difficult to measure accurately, especially in low-data regions.
3. Some goals can conflict with short-term economic interests.

The Planetary Boundaries Model

1. The planetary boundaries model identifies nine critical Earth systems that regulate the planet's stability and resilience.
2. It defines safe operating spaces for human activities, warning that crossing these boundaries increases the risk of abrupt and irreversible environmental changes.

The Nine Planetary Boundaries

1. Climate Change
2. Biosphere Integrity (Biodiversity Loss)
3. Land-System Change
4. Biogeochemical Flows (Nitrogen and Phosphorus Cycles)
5. Freshwater Use
6. Ocean Acidification
7. Atmospheric Aerosol Loading
8. Stratospheric Ozone Depletion
9. Novel Entities (Chemical Pollution)

Which Boundaries Have Been Exceeded?

1. Scientists confirmed that 6 of the 9 boundaries have been crossed.
2. Safe operating space (green zone) is shrinking, while “high-risk zones” (red/orange) expand.
   1. Biodiversity Loss: species are declining rapidly; extinction rates are 100–1000× faster than natural background levels.
   2. Biogeochemical Flows: excess nitrogen & phosphorus from fertilizers → eutrophication & dead zones.
   3. Land-System Change: widespread deforestation and habitat conversion.
   4. Climate Change: atmospheric CO₂ levels exceed safe threshold (~350 ppm) and continue rising.
   5. Novel Entities (pollutants like plastics and PFAS): accumulating faster than ecosystems can absorb.

Uses of the Planetary Boundaries Model

1. Science-Based Limits: Provides a framework for understanding the thresholds of Earth's systems.
2. Holistic Perspective: Highlights the need to address multiple environmental issues, not just climate change.
3. Policy Guidance: Informs decision-makers about the urgency of sustainable practices.

Limitations of the Model

1. Primarily ecological, lacking explicit social or economic dimensions.
2. Uncertainty in data: Boundaries are continuously refined as new data emerges.
3. Global boundaries may not reflect regional variations—some areas reach limits earlier than others.
4. Overlaps between boundaries (e.g., land-use and climate) make them difficult to isolate.

Doughnut Economics Model

1. The model was developed by Kate Raworth, an economist at Oxford University.
2. The model proposes a framework for achieving sustainable and equitable development.
3. It visually resembles a doughnut with two boundaries: