Cumulative effects can be difficult to predict and manage due to inadequate environmental baseline data, complex ecological processes, and the large scale at which human development occurs.
Some activities known to have significant impacts on the environment and contribute highly to cumulative effects are marine resource development, energy production and consumption, and land use changes.
[4] The emergence of cumulative effects considerations in environmental regulations began in the late 1970s when it was realized that proposed development projects should not be assessed in isolation from surrounding land uses.
[7] In some instances, multiple activities may cause a single, common stressor; for example, a factory and a nearby landfill may both release polluting run-off into a river.
Marine ecosystems experience environmental impacts from a range of marine-related activities, such as shipping, fishing, offshore oil and gas industries, and deep-sea mining.
[11] The energy production sector can result in many negative impacts on the environment, such as air pollution, acid rain, deforestation, emission of radioactive substances, and ozone depletion, all of which contribute to climate change.
[12] Energy production is associated with large amounts of infrastructure, such as power plants, pipelines, wind and solar farms, and dams, which contribute to the environmental effects of land use change.
The consumption of energy by industrial and domestic activities, particularly fossil fuels, are known to have significant impacts on global warming by emitting large amounts of greenhouse gases.
[17] Because of the project-specific nature of most environmental assessment work, the data resulting from their studies are not in line with the needs of cumulative effects analyses.
The approach scientists take to cumulative effects research and the information environmental assessment practitioners and land managers need to make decisions are disconnected: scientists typically focus cumulative effects research on the responses of ecological components to stressors, while decision-makers are interested in understanding the connection between human activities and stressors.
[17] Many tools and methods for cumulative effects studies have been developed, however, there is no approach that is universally accepted by land managers, scientists, and environmental assessment practitioners.
[2] Some researchers have published methodologies for cumulative effects studies, but they have generally been developed in relation to individual projects and therefore cannot be applied to broader contexts.
[20] Landscape management, such as creating wildlife reserves, will help to ensure human development can not occur there and therefore reduce cumulative effects in that area.
This paradox presents itself in the United States under the National Environmental Policy Act where it is required to assess cumulative effects in reaching a decision regarding proposed activities.
Under this principle, the significance of proposed activities' impacts are assessed in terms of the degree to which they would change the existing cumulative effect baseline.