Summary
Highlights
The word 'sustainable' is frequently used with vague and inconsistent meanings, applied to everything from sustainable cotton to sustainable coal. This vagueness stems from two issues: the 'focus problem' (addressing only one aspect of sustainability) and the 'numbers problem' (something being 'more sustainable' than something worse, but not truly sustainable). This misuse leads to misleading claims, confusion, and ineffective policies.
The most widely accepted definition of sustainability, the Bruntland definition from 1987, focuses on meeting present needs without compromising future generations. While a good start, it's still too vague regarding what constitutes a 'need'. Despite decades, a more accurate, quantifiable definition has not been broadly adopted, leading to ongoing uncertainty.
The speaker proposes 'absolute sustainability', defining something as sustainable if it is able to sustain itself into the future without putting too much strain on the planet. This concept became more personal after she became a parent, highlighting the importance of securing the future for coming generations. To achieve this, it's crucial to define and quantify sustainability.
Absolute sustainability is achieved by determining how much a product or activity is 'allowed' to impact the Earth across multiple environmental aspects (not just climate change, but also water, land, biodiversity). This approach solves both the numbers and focus problems by comparing actual impact with a clearly defined allowance, providing a 'yes' or 'no' answer to whether something is truly sustainable. The core principle is 'sticking to your share'.
To understand one's share, an analogy of sharing a cake (representing the Earth's resources) is used. Three questions are essential: how big is the cake (the size of available resources), who wants to share it (everyone, including future generations), and how to share it. The 'planetary boundary framework' provides quantifiable limits for how much we can strain the planet in nine environmental areas, defining the size of the 'cake'.
The third question, 'how to share the cake', involves a blend of engineering science and philosophy. Researchers have converted philosophical approaches to sharing into mathematical equations to calculate whether something is absolutely sustainable. This revolutionary approach aims to turn the question of sustainability into a scientific one with a definitive 'yes' or 'no' answer, emphasizing that 'better is not good enough'.