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:
   1. Inner Boundary: The Social Foundation
   2. Outer Boundary: The Ecological Ceiling

The Inner Boundary (Social Foundation)

1. Represents the minimum social standards needed for human well-being.
2. Based on the social SDGs, such as food security, education, healthcare, and political voice.
3. Billions of people still fall below this foundation, lacking access to basic needs.
4. Key elements include:
   1. Food security and adequate nutrition
   2. Access to clean water and sanitation
   3. Health care and physical well-being
   4. Education and lifelong learning
   5. Income and decent work opportunities
   6. Gender equality and social equity
   7. Political voice, peace and justice
   8. Housing, networks and energy access

The Outer Boundary (Ecological Ceiling)

1. Represents planetary limits that must not be exceeded to prevent environmental collapse.
2. Based on the Planetary Boundaries model, including climate change, biodiversity loss, and pollution.
3. Humanity has already overshot many planetary boundaries, putting ecosystems at risk.
4. Includes:
   1. Climate stability
   2. Biodiversity integrity
   3. Clean air quality
   4. Sustainable freshwater use
   5. Fertile soils and nutrient balance
   6. Control of pollution and chemical safety
   7. Ocean health and acidification limits

Key Concepts in Doughnut Economics

1. Regenerative Design: Works with nature instead of exploiting it.
2. Distributive Design: Ensures that wealth, power, and resources are equitably shared.

Uses of the Doughnut Economics Model

1. Integrates Social & Ecological Concerns: Unlike traditional economic models, it considers both human well-being and environmental sustainability.
2. Supports Environmental Justice: Ensures that economic benefits are fairly distributed while respecting planetary boundaries.
3. Used at Different Scales: Applied in cities (e.g., Amsterdam), businesses, and national policies to promote sustainable practices.

Limitations of the Model

1. Lacks Specific Policy Proposals: Provides broad principles but does not outline concrete steps for implementation.
2. Still in Development: Different groups interpret and apply the model in different ways, leading to varied effectiveness.
3. Challenging to Implement: Transitioning to a regenerative and distributive economy requires major systemic changes.

The Circular Economy

1. Unlike the linear economy (take-make-waste), the circular model reduces waste and regenerates natural systems.
2. The resources are reused, repaired, refurbished, and recycled to extend their lifespan.
3. The circular economy is based on three core principles:
   1. Eliminate waste and pollution: Design products and systems that prevent waste from being created in the first place.
   2. Circulate products and materials: Keep materials in use for as long as possible through reuse, repair, remanufacturing, and recycling.
   3. Regenerate nature: Restore and enhance natural systems by returning valuable nutrients to the soil and reducing resource extraction.

Uses of the Circular Economy

1. Reduces Waste and Pollution: Less landfill and ocean plastic through product lifecycle extension.
2. Cuts Greenhouse Gas Emissions: Less raw material extraction and lower energy demand.
3. Supports Local Economies: Encourages repair businesses, local food systems, and green jobs.
4. Changes Consumer Habits: Encourages sharing economies (e.g., rental models, repair cafés) and sustainable consumption.

Advantages of the Circular Economy

1. Reduces resource extraction and dependency on finite materials.
2. Minimizes waste generation and pollution.
3. Enhances economic resilience by creating repair, recycling, and service industries.
4. Generates green jobs and supports local economies.
5. Encourages innovation in product design and sustainable technologies.
6. Contributes directly to climate change mitigation through lower energy demand.

Limitations of the Circular Economy

1. Transition can be expensive and technically complex, especially for small firms.
2. Requires infrastructure for waste collection, sorting, and recycling.
3. Not all materials are infinitely recyclable; quality degrades over time.
4. Consumer habits and cultural preferences may resist change.
5. Inconsistent policy and regulation across countries hinder adoption.
6. Risk of greenwashing, companies claiming circularity without genuine implementation.

Linear vs. Circular Economy

The Butterfly Diagram: A Visual Guide

1. The Butterfly Diagram, created by the Ellen MacArthur Foundation, illustrates how the circular economy works.
2. It highlights two key cycles:
   1. Biological Cycle: Focuses on renewable resources like food and organic materials. These can be composted or processed to regenerate natural systems.
   2. Technical Cycle: Deals with non-renewable resources like metals and plastics. These materials are kept in use through repair, reuse, and recycling.