What Is a Climate Tipping Point?
A climate tipping point is a critical threshold beyond which a natural system undergoes a significant, often irreversible change, even if the driving forces…
Evidence library
Joaquimma Anna
Research, explainers and solution analysis for understanding change across a living planet.
201 resources
What Happens When a Planetary Boundary Is Transgressed?
Transgression of a planetary boundary means that a key Earth-system control variable has moved beyond the proposed safe operating space, entering a zone of…
Planetary Boundaries and Doughnut Economics: A Comparison of Earth-System Frameworks
The Planetary Boundaries framework defines a safe operating space for humanity based on nine Earth-system processes, while Doughnut Economics combines an ecological ceiling derived…
What Is a Circular Business Model? A Comprehensive Analysis
A circular business model is an economic framework that aims to decouple growth from resource consumption by designing out waste, keeping products and materials…
How to Evaluate an Environmental Claim: Key Statistics and Trends
In 2021, a sweep by the European Commission and national consumer authorities found that 42% of green claims on websites were exaggerated, false, or…
How to Read an Environmental Chart: The Keeling Curve and Atmospheric CO₂
The Keeling Curve shows the latest atmospheric CO₂ concentration at Mauna Loa Observatory: 426.55 parts per million (ppm) in February 2025, as reported by…
Why the Oceans Absorb Carbon Dioxide
The oceans absorb carbon dioxide from the atmosphere because of a natural chemical equilibrium: CO2 dissolves in seawater and reacts with water to form…
What Is Doughnut Economics? A Comprehensive Explainer
Doughnut Economics is a visual framework for sustainable development that combines the concept of planetary boundaries with the concept of social boundaries. It defines…
Nitrogen Pollution Explained: Causes, Impacts, and Solutions
Nitrogen pollution is the excessive release of reactive nitrogen compounds into the environment, primarily from agriculture, industry, and transportation. It disrupts ecosystems, harms human…
How Agriculture Changes the Global Water Cycle
Agriculture profoundly alters the global water cycle by withdrawing massive amounts of freshwater for irrigation, modifying land surfaces, and releasing pollutants. These changes affect…