Everything You Need to Know About Planetary Boundaries
Planetary boundaries, a key concept in understanding the overall health of our planet, evoke both fascination and concern. They are frequently used by policymakers in their speeches and also in reports from the Intergovernmental Panel on Climate Change (IPCC) to assess the ecological situation.
As 2024 has just begun, let's take stock of the boundaries that have already been exceeded and the outlook for the concept.
What are "planetary boundaries"?
"The concept of planetary boundaries is a method of assessing and monitoring environmental changes caused by humans that may threaten the stability of ecosystems. By highlighting warning signals, this concept defines the conditions to preserve a 'safe operating space for humanity.'"
[Source:https://www.vie-publique.fr/questions-reponses/291386-les-limites-planetaires-en-six-questions]
Established in 2009
It was in 2009 that the concept of "planetary boundaries" was developed by researchers at Stockholm University in Sweden. These boundaries define limits that should not be crossed for Earth to operate without suffering irreversible damage. Indeed, exceeding them would lead to a tipping point in planetary balances.
What are they used for?
To what extent are we disrupting Earth's balance? It is particularly interesting to delve into the concept of planetary boundaries to answer this question. It is also crucial to keep in mind that these 9 boundaries are interconnected. In this sense, a potential innovative solution for one of the 9 points may jeopardize one or more of the other boundaries.
Take agrofuels as an example: while they do help mitigate climate change by replacing gasoline, widespread use of these new fuels could potentially exceed the land use limit to cultivate enough agricultural products to produce them.
2024 Assessment: Which boundaries have already been exceeded?
The nine planetary boundaries defined by Swedish scientists are as follows:
Climate Change
Biodiversity Integrity
Biochemicals Flows
Freshwater Change
Stratospheric Ozone Depletion
Ocean acidification
Land-system Change
Atmospheric Aerosol Loading
Novel Entities
While 6 out of the 9 boundaries have already been exceeded by September 2023, the remaining 3 (ocean acidification, depletion of the ozone layer, and atmospheric pollution) are degrading and will be crossed without global actions.
A debated concept
Firstly, the concept of planetary boundaries is far from being the only indicator used to assess the impact of human activities on the environment. Among the tools advocated by the scientific community is the concept of the "Overshoot Day." This marks the date when humanity has consumed all the resources that the Earth can regenerate in a year. It is the day when our ecological footprint exceeds the planet's capacity to regenerate. In summary, planetary boundaries focus on environmental thresholds not to be exceeded to maintain ecological stability, while the Overshoot Day highlights humanity's annual overconsumption of resources. Therefore, these two complementary concepts should not be confused.
Moreover, the concept of planetary boundaries has intrinsic limitations. As they are defined on a global scale, it is challenging to apply them at regional and local levels. Additionally, some scientists have sought to enrich the concept of planetary boundaries by incorporating human needs. This is evident in economist K. Raworth's "Doughnut Theory," which establishes a sustainable zone for humanity between the "ceiling" of human activities (corresponding to planetary boundaries) and the "floor" representing human needs.
And what about sustainable building?
Planetary boundaries are easily applicable to the field of sustainable building. Sustainable practices align with each of the 9 boundaries to decarbonize and make the building sector more resilient. The nine planetary boundaries is a good framework to challenge sustainable building practices and minimize the ecological footprint of urbanization. For example:
Climate change
Sustainable architecture supports greenhouse gas emissions reduction and improved energy efficiency through low carbon design applied throughout a building’s lifecycle.
Biodiversity Integrity
Sustainable construction projects strive to foster a positive impact on biodiversity by adopting practices such as preserving natural habitats, limiting noise and light pollution, and designing wildlife-friendly landscapes.
Biochemical Flows
Sustainable buildings integrate on site wastewater management which reduces soil and water pollution, contributing to respecting the limits related to nitrogen and phosphorus cycles.
Freshwater Change
Sustainable buildings incorporate water management systems, such as rainwater harvesting and water-saving technologies, to meet human needs while respecting the limit of freshwater use.
Ozone Layer
The gradual elimination of ozone-depleting substances in building materials aligns with sustainable practices, contributing to ozone layer protection. Furthermore, sustainable buildings prioritize locations that are close to public transportation networks to ensure good site connectivity. As a result, the reliance on combustion vehicles decreases, limiting the noxious consequences of these vehicles on the ozone layer.
Ocean acidification
The phenomenon of ocean acidification is mainly caused by the accumulation of CO2 stored in the oceans. By minimizing greenhouse gas emissions and promoting environmentally friendly construction practices, sustainable buildings contribute to reducing indirect impacts on the oceans, thus preserving marine biodiversity.
Land-system Change
Sustainable construction projects often prioritize site rehabilitation over expansion on virgin lands, contributing to biodiversity preservation and respecting land use limits.
Atmospheric and chemical pollution
Sustainable construction standards and technologies aim to reduce aerosol and air pollutant emissions, improving local air quality. Indeed, by prioritizing low-emission materials and preferring locations close to public transportation, sustainable buildings help reduce air and chemical pollution by decreasing the reliance on combustion vehicles.
Conclusion
In conclusion, with this article, we aimed to demystify the concept of planetary boundaries, identify areas where these crucial thresholds have been crossed, and analyze the debates surrounding this complex notion. By highlighting these often alarming realities, we are called to reflect on our impact on Earth and consider innovative solutions to preserve the delicate balance of our global ecosystem.
Although planetary by definition, the 9 boundaries are applicable at the local level and in specific sectors. In the case of sustainable building, it is wise to keep these planetary boundaries in mind to guide sustainable construction initiatives and redirect the building industry towards more environmentally friendly practices. Using these indicators intelligently allows us to identify "false good" solutions and avoid the rebound effect associated with certain technological innovations.
