Cumulative Impacts Project
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'Cumulative impacts' refers to the total harm to human health and the environment that results from combinations of assaults and stressors over time. The Cumulative Impacts Project is dedicated to promoting science, law, and policy that will reduce cumulative impacts.
Law Science Policy

About the Cumulative Impacts Project

Adverse effects can add up until they surpass the limits of an individual's or system's ability to withstand them. Factors that can contribute to these assaults include socioeconomic and psycho-social experiences, nutrition, toxic exposures, gene-environment interactions, infectious disease, and disruptions in climate patterns, among others. They seldom add up predictably but are complicated by interactions, synergism, compounding, feedback loops, and other mechanisms that create uncertainty but also suggest crosscutting, preventive solutions.

Our laws and decision-making structures have either ignored cumulative impacts or called for addressing them without saying how. This is beginning to change, however. This website aims to move that conversation forward by pooling information on cumulative impacts in three scopes:

Ecosystems—local, planetary, climate change
Communities—environmental justice and vulnerable populations
Human health—multiple factors in disease and disability

These three scopes represent different aspects of the problem of cumulative impacts and leverage points for addressing it. They also overlap and affect each other. Together they call for new precautionary decision structures and initiatives aimed at reducing total environmental impacts. This website, from the revolving photos on the homepage to the "topical search" matrix on the search page, embodies those interconnections.

The primary goal of the Cumulative Impacts Project is to collect the latest science, emerging best practices, analytical tools, and legal shifts that can reduce cumulative harm to our planet, our communities, and ourselves.

Contact us to learn more, suggest resources, and add your ideas.

Cumulative Impacts Working Group

You are welcome to join the Cumulative Impacts Working Group listserv to receive notice of monthly conference calls and other developments. The calls focus on a particular project or issue related to cumulative impacts on human health and the environment, often with one presenter followed by discussion.

To access recordings of past calls type "cumulative impacts working group" in the text bar on the Search page (include quotes).

We hope you will join us!


This is a project of the Science and Environmental Health Network (SEHN) and the Collaborative on Health and the Enivronment (CHE), along with an advisory group of environmental justice advocates, scientists, scholars, and agency staff members.

Website coordinator: Nancy Myers, SEHN; design and technical assistance, Nancy Hepp, CHE; DG Communications.

Working group coordinators: Elise Miller, CHE; Carolyn Raffensperger, SEHN