A CU Boulder study reveals over 99% of the world’s population faces threats to environmental human rights, including polluted air and unsafe water. Nearly half endure three or more environmental crises, demanding urgent global climate action. What does this mean?

A new analysis from the University of Colorado at Boulder reveals a shocking scale of global environmental injustice: more than 99% of the world’s 7.7 billion people have at least one of their environmental human rights threatened.

Published in Environmental Research Communications on September 25, the peer-reviewed study provides undeniable evidence that environmental risks are not isolated incidents but a widespread violation of rights, underscoring the urgent need for action as global leaders prepare for the COP30 climate summit in Brazil.

Widespread threats to environmental rights

The CU Boulder research, the most comprehensive of its kind, meticulously assessed the global population’s exposure to conditions that violate five core environmental rights defined by the UN in 2022: clean air, clean water, a safe climate, healthy and sustainably produced food, and thriving biodiversity and ecosystems.

The findings are stark:

• Nearly everyone on Earth (over 99%) has recently experienced conditions that threatened at least one of the five core environmental rights.
• Almost half of the global population (over 45%, or 3.4 billion people) live in regions facing three or more environmental problems simultaneously.
• 95 million people (1.25%) endure threats to all five core environmental rights.

First author Naia Ormaza-Zulueta, a doctoral student, emphasised the goal of the research: “We want to stitch their stories into a single, undeniable global tapestry so that they can’t be dismissed as isolated problems.”

The most common threat identified was a lack of access to clean air, defined as annual average outdoor particulate matter concentration below the World Health Organisation guideline, followed by a lack of access to healthy and sustainably produced food.

Disproportionate impact and global hotspots

While environmental risks are near-universal, their impacts are felt disproportionately. The study confirms that disadvantaged populations—including those with lower incomes, displaced persons, and communities on Indigenous lands—are significantly more likely to experience the worst of poor air quality, limited clean water, and extreme heat. Furthermore, those in wealthier areas often enjoy the best environmental conditions and are better positioned to escape the most severe consequences of climate change.

Internationally, specific regions face concentrated injustice:

• South Asia emerged as a critical hotspot, containing 41% of all people living with all five threats to environmental rights, despite accounting for only one-fifth of the world’s population.

Data scientist Zia Mehrabi highlighted that these statistics likely underestimate the true extent of the problem, as they do not account for other unmeasured poor conditions, such as exposure to toxins from mining and plastic waste.

Pollution without borders: The role of wealthy nations

The research provides compelling evidence that the activities of wealthy, industrialised nations heavily influence the poor environmental conditions globally. This highlights a critical flaw in the 2022 UN resolution, which failed to account for environmental harm caused by activities in other countries.

The study presented several shocking examples of this transnational impact:

• Pollution from the United States is responsible for an estimated 12,000 deaths from poor air quality in India and 38,000 deaths in China annually.
• Emissions from the 27 countries in the European Union have made extreme weather events 1.8 times more likely in Southeast Africa and the Amazon rainforest.

“No matter where we live, our rights are inherently connected to those of people in other parts of the world,” said Ormaza-Zulueta, pointing out that the high demand for products in the U.S. and Europe drives biodiversity loss and deforestation in regions like the Amazon.

A call for accountable policy

The researchers stress that the bleak statistics must spur action. They call for strong policies to encourage businesses to adopt solutions, ranging from responsible clean energy to more sustainable and just supply chains. Mehrabi specifically referenced the need for other nations to follow the lead of countries like the Netherlands, France, and Germany, which have implemented due diligence laws requiring domestic companies to uphold human rights across their global operations.

The study is intended to be an empowering tool for environmental rights advocates. By providing a global, aggregated view of these injustices, the research team hopes “deniers can no longer dismiss the polluted river here or dirty air there as anecdotes,” which could be “a critical tool for pushing for policy changes.”