Introduction of Novel Entities
The introduction of synthetic chemicals, plastics, and other human-made materials into Earth’s systems.
Current State
Novel entities comprise human-made chemicals and materials and naturally occurring substances that are mobilized by humans. Produced and released in myriad forms and huge quantities, they can interact, accumulate and elicit impacts in ways that can threaten the Earth system. For example, many novel entities (certain pollutants and plastics) are widespread globally with poor reversibility. They accumulate along the food chain and cause adverse effects, by themselves or in combination with other stressors (e.g., heat or drought), ultimately with the potential to threaten biosphere integrity.
However, our understanding of planetary-scale exposure and impacts is still fragmented due to the tremendous, ever-increasing number and diversity of novel entities. To assess the potential planetary risk arising from our ignorance, we use a practical proxy: the proportion of novel entities that does not undergo adequate safety testing before widespread production and use. That share is currently very high, and on this basis the Planetary Boundary for Novel Entities is considered transgressed – the creation of novel entities far outpaces our capacity to evaluate them. Future assessments may incorporate additional metrics, such as production, release to the environment, transport to and accumulation in remote sinks, and impacts.
Impacts
Novel entities are now found in every part of the planet — from mountain soils to ocean depths. Some trap heat in the atmosphere, others harm plants and animals, and many build up in food webs or water systems. Once released, they are difficult or impossible to remove, meaning their effects can last for centuries.
Pollution spreading through ecosystems
Pesticides and industrial chemicals wash into rivers and soils, harming insects, fish, and birds. Pollinators are declining, and microplastics are turning up in marine life and even in drinking water. These pollutants weaken ecosystems and reduce biodiversity.
Long-lasting contamination
Because many of these substances don’t break down easily, they accumulate over time. Radioactive materials and heavy metals can linger in soil and water for centuries, causing lasting harm to people and nature. Substances like PFAS are another example: Used in countless products, from cookware to clothing, they are now found in water, wildlife, and even human blood across the globe — including in remote areas like the Arctic.
Links to climate and air quality
Some novel entities also contribute to other planetary pressures. Fluorinated gases trap heat and add to global warming, while particles and industrial chemicals released into the air worsen pollution and damage human health.
Unknown and unpredictable risks
One of the biggest dangers of novel entities is how little we understand their long-term effects. Thousands of chemicals are released every year, many with unknown interactions in the environment or with living organisms. Some may seem harmless at first but could accumulate or react in ways that cause unexpected harm over time. These hidden and unpredictable risks make it difficult to manage novel entities safely — and highlight how much we still don’t know about their full impact on people and the Earth system.
Sunita Narain, Environmentalist and author, Director General of the Centre for Science and Environment and Editor of Down To Earth, Planetary Guardian.
“We would not allow one of our own organs to fail, so we can’t standby with seven of the nine planetary boundaries already breached, causing potential catastrophic risk of failure to humanity’s life support system. This is even more urgent as the impacts of this failure will cause unimaginable suffering for the people who did not cause these breaches.”
Sunita Narain, Environmentalist and author, Director General of the Centre for Science and Environment and Editor of Down To Earth, Planetary Guardian.
Key Drivers
Runaway chemical production
The world now produces and uses more chemicals than ever before. Thousands of new compounds are created each year, outpacing the ability to study or regulate them safely. Many reach the market without thorough safety checks. Limited monitoring and slow regulation mean harmful substances can stay in circulation long after their dangers are known.
Mixing effects and knowledge gaps
Pollution rarely comes from one substance alone. Chemicals can mix and react in complex ways that scientists are only beginning to understand, creating new risks for people and ecosystems.
Old pollution that never goes away
Legacy pollutants — such as microplastics, heavy metals, and radioactive waste — continue to leak into air, soil, and water. Even if production stopped today, their impacts would still be felt for generations.
Control Variables
The Planetary Boundary for Novel Entities covers a wide range of human-made materials and substances — including synthetic chemicals, heavy metals, plastics, radioactive materials, and even genetically modified organisms. Together, they represent a growing and complex pressure on the Earth system, but their combined impacts are hard to measure. For now, the boundary is tracked through the percentage of untested chemicals in use worldwide. This share has grown rapidly as chemical production expands far faster than our ability to test or regulate it. As a result, the boundary has been transgressed, marking a clear warning that humanity is introducing new substances into the environment faster than we can ensure they are safe.
Percentage of synthetic chemicals released to the environment without adequate safety testing
From conception to contamination: The rise of novel entities. This figure exemplifies the trends of production (Plastics, High-Value Chemicals), application (Antibiotics, Pesticides) and release (PFAS) of different novel entities. Production of many human-made substances such as plastics, antibiotics, pesticides and harmful chemicals is steadily rising, posing significant threats to the Earth system – as well as human health.
Definition
The share of human-made or -mobilized chemicals and materials released into or mobilized in the environment without adequate safety testing. This control variable reflects our level of understanding of the risks of novel entities and how effective regulations are. Monitoring this share is essential for managing the potential impacts these substances may have on the Earth system.
Unit
Percentage, i.e. the fraction of synthetic chemicals and materials released without adequate safety testing.
Historical Range
This percentage can vary from 0% (all chemicals and materials undergo sufficient testing before release) to 100% (none are tested).
Planetary Boundary (PB)
Following the precautionary principle, the Planetary Boundary of Novel Entities is set at 0 % – no human-made or -mobilized chemicals and materials should be released or mobilized without adequate safety testing. Examples of novel entities include polychlorinated biphenyls (PCBs), which, even decades after their ban in the Stockholm Convention, are still present in the Earth system and partly exceed effect thresholds in marine mammals; or the global spread of highly persistent per- and polyfluoroalkyl substances (PFASs). Such examples underscore the need for strict testing before large-volume production and use. Other aspects that require consideration are the environmental transport and transformation of novel entities which may result in transformation products that are more toxic than the original chemicals. An example is a tire wear-derived oxidation product of the additive 6PPD-quinone, which was found to induce acute mortality in coho salmon and other fish species of commercial, cultural and ecological importance.
