# Sufficiency: the forgotten sustainability strategy | Joost Declercq | TEDxBrussels Source: https://www.youtube.com/watch?v=TkOtTIywX0g Recap page: https://rapidrecap.app/video/TkOtTIywX0g Generated: 2026-02-09T16:38:18.938+00:00 --- ## Quick Overview The forgotten sustainability strategy is Sufficiency, which focuses on doing the right things rather than just doing things right (Efficiency), because relying solely on efficiency and renewables leads to increased consumption, potentially resulting in a 4 to 5 degree Celsius temperature rise in homes and significant material carbon emissions from new construction. **Key Points:** - Relying only on Efficiency and Renewables leads to a significant increase in total energy use, potentially causing a 4 to 5 degree Celsius temperature rise in homes over 40 years. - The building sector contributes 40% of global CO2 emissions and 30% of global waste, highlighting the need for systemic change beyond just energy efficiency. - The speaker advocates for the third strategy, Sufficiency, which questions what we truly need, exemplified by retrofitting existing buildings instead of building new ones. - Retrofitting existing buildings, like the Greenpeace office or the former Fabrimetal headquarters in Brussels, can be done effectively without demolishing or using excessive new materials. - Efficiency (doing things right) and Sufficiency (doing the right things) are interconnected; for example, a 1-degree Celsius temperature reduction in homes can yield 5% to 10% energy savings. - The presentation emphasizes that the climate urgency demands that we avoid errors, suggesting that current efforts focused only on efficiency and renewables are insufficient to meet the 1.5°C target. ![Screenshot at 01:39: A graph illustrating that energy use per carrier \(building energy use\) has barely decreased over 40 years \(1990-2020\) despite efficiency efforts, contrasting sharply with the steep decline required to meet the 1.5°C climate goal.](https://ss.rapidrecap.app/screens/TkOtTIywX0g/00-01-39.jpg) **Context:** Joost Declercq presents at TEDxBrussels on the three core strategies for sustainability in the built environment: Efficiency, Renewables, and Sufficiency. He argues that the first two alone are insufficient to meet climate goals, pointing to historical data showing rising energy use despite efficiency gains. The talk contrasts building new structures with retrofitting existing ones, using examples like the Greenpeace office and a former factory converted into offices in Belgium, to advocate for a fundamental shift in mindset toward sufficiency. ## Detailed Analysis The speaker, Joost Declercq, identifies three key strategies for sustainability: Efficiency, Renewables, and Sufficiency. He asserts that Efficiency (doing things right) and Renewables alone are failing, as historical data shows that energy use in buildings has barely decreased over 40 years (1990-2020), putting the world on track for a potential 4 to 5 degree Celsius temperature increase in homes. The building sector is responsible for 40% of global CO2 emissions and 30% of global waste. The third strategy, Sufficiency (doing the right things), is crucial. This involves questioning necessity, such as whether to build new structures or retrofit existing ones. He shows examples of successful retrofitting, like the Greenpeace office and the former Fabrimetal administrative center in Brussels, demonstrating that existing buildings can be optimized without massive demolition or material carbon expenditure. He notes that the embodied carbon in structure, façade, and roof accounts for 46% of a building's total carbon footprint. Furthermore, achieving a 1°C reduction in heating/cooling setpoints yields a 5% to 10% energy saving, linking comfort expectations to climate outcomes. The urgency of the climate crisis means there is no room for error, making Sufficiency a necessary component alongside efficiency and renewables. ### The Three Strategies - Efficiency involves doing things right (using less energy for the same function); Renewables involve using clean energy sources; Sufficiency involves doing the right things (questioning the need for excess comfort/space). ### The Failure of Current Trends - Historical data shows building energy use has barely decreased since 1990, setting a trajectory for 4-5°C temperature rise in homes, while the Paris Agreement requires a sharp decline post-2025. ### Building Sector Impact - The building sector is responsible for 40% of global CO2 emissions and 30% of global waste, with 46% of embodied carbon residing in the structure, facade, and roof. ### The Power of Sufficiency - Retrofitting existing buildings (like the examples shown from Brussels) achieves sustainability goals without extensive new material use, contrasting with building new structures. ### Comfort and Metabolism - Recent research shows that 'healthy discomfort'—small temperature differences from the comfort zone (e.g., 1°C difference) or physical activity—positively impacts metabolism, leading to better energy/weight balance and insulin sensitivity. ![Screenshot at 00:00: TEDxBrussels Countdown event stage setup with dinosaur skeletons in the background.](https://ss.rapidrecap.app/screens/TkOtTIywX0g/00-00-00.jpg) ![Screenshot at 01:21: A diagram illustrating a sustainable house design, showing integrated systems like solar panels and geothermal storage.](https://ss.rapidrecap.app/screens/TkOtTIywX0g/00-01-21.jpg) ![Screenshot at 01:47: Slide stating "60% of the gains are lost" due to increasing size and energy demand of future housing.](https://ss.rapidrecap.app/screens/TkOtTIywX0g/00-01-47.jpg) ![Screenshot at 04:08: Image of a modern McDonald's building highlighting a 60% cooling load reduction achieved through smart design.](https://ss.rapidrecap.app/screens/TkOtTIywX0g/00-04-08.jpg) ![Screenshot at 05:23: Slide illustrating the 'Efficiency, Renewables, Sufficiency' framework as three interlocking components.](https://ss.rapidrecap.app/screens/TkOtTIywX0g/00-05-23.jpg)