About cumulative effects

• The term “cumulative effects” generally refers to the combined effects from past, present, and reasonably foreseeable future activities and natural processes. Specific definitions vary among different parties and under different legislation and policies, but the term generally refers to effects that may be individually minor, but collectively significant. Effects can be adverse (for example, deteriorated water quality in a regional river) or positive (e.g., socioeconomic benefits to a local community).
• Cumulative effects form a complex and overarching issue. Because so many parties may be implicated, leadership and coordination are key. Leadership will depend upon the parties involved and their respective jurisdictions, authorities, and efforts to understand, consider, and manage cumulative effects.
• In a world of increasing development pressures and changing natural processes, it is important to understand, consider, and support the management of cumulative effects for the environment, socio-economic conditions, and human health. 

• Section 35 of the Constitution Act, 1982 explicitly recognizes and affirms the existing Aboriginal and treaty rights of the Aboriginal peoples of Canada. Cumulative effects can result in impacts to the Aboriginal and treaty rights, as well as the broader interests, of Indigenous peoples. An understanding of how cumulative effects may impact rights and interests – which may have a distinct regional and historical context and be more holistic in nature – can result in a more nuanced and accurate consideration of cumulative effects.  This, in turn, can better inform decision-making.
• For example, multiple effects resulting from past, existing, or future development or events, such as loss of contiguous habitat, increased hunting and predators, and stress from forest fires, may result in cumulative effects to wildlife, including species at risk. This, possibly combined with other past and future effects – such as decreased access to hunting areas, reduced quality and quantity of culturally important species, and existing impacts to the intergenerational transmission of knowledge and cultural practices – may result in impacts to the ability of Indigenous peoples to exercise their hunting rights and way of life, including rights related to culture and to the intergenerational transmission of knowledge.

• The Government of Canada acknowledges the importance of improving the understanding of cumulative effects in general (not just for federal impact and environmental assessment processes) and their impacts on the rights and interests of Indigenous peoples. This work takes place in the context of:
  • The commitment to “achieving reconciliation with Indigenous peoples through a renewed, nation-to-nation, government-to-government, and Inuit-Crown relationship based on recognition of rights, respect, co-operation, and partnership as the foundation for transformative change”.^{Footnote 3} 
  • The implementation of the United Nation Declaration on the Rights of Indigenous Peoples Act. 
• The Government of Canada has a duty to consult and, where appropriate, accommodate Indigenous peoples when it has knowledge, real or constructive, of established or asserted Aboriginal or treaty rights and contemplates conduct that may adversely affect those rights. In dialogue, Indigenous peoples may raise cumulative effects as a concern arising from the contemplated Crown conduct on the rights and interests of Indigenous peoples. Cumulative effects form part of the context that should be taken into consideration when assessing the seriousness of potential impacts to rights and interests. Depending on the circumstances, some impacts from a new conduct could be accommodated through avoidance, reduction, mitigation, compensation measures or a combination of these measures.
• Working together with Indigenous peoples is a key part of federal impact and environmental assessment processes. This includes working in a manner that promotes reconciliation, respects the rights and cultures of Indigenous peoples in a way that makes the exercise of their rights meaningful, and protects and ensures the inclusion of Indigenous knowledge. More robust decision-making is supported by an understanding of cumulative effects informed by Indigenous Knowledge and of how these effects impact the rights and interests of Indigenous peoples.

• Outside the context of project-specific assessment processes, the Government of Canada has developed a number of initiatives and processes to improve the understanding, consideration, and support for the management of cumulative effects regionally or nationally.  Here are some examples:
  • The Impact Assessment Agency of Canada is leading on several regional assessments. Regional assessments are studies conducted in areas of existing projects or anticipated development to inform planning and management of cumulative effects and inform project impact assessments. Regional assessments allow the Government of Canada to go beyond project-specific impact assessments to understand the regional context and provide more comprehensive analyses to help inform future impact assessment decisions.
  • The Government of Canada continues to work to add, gather, enhance and make publicly available the data and information needed to support understanding and consideration of cumulative effects on ecosystems, society and the economy, and associated effects on health and well-being.  The Open Science and Data Platform for cumulative effects brings together data and science dispersed across federal and some provincial and territorial systems and websites.
  • The Cumulative Effects of Marine Shipping Initiative involves working with Indigenous peoples and stakeholders to assess the cumulative effects of marine shipping activities in 6 areas across Canada: North Coast British Columbia; South Coast British Columbia; St. Lawrence and Saguenay Rivers, Quebec; Bay of Fundy, New Brunswick and Nova Scotia; Placentia Bay, Newfoundland; and Cambridge Bay, Nunavut.
  • The Government of Canada has made clear and ambitious commitments toward the establishment of protected areas, including Indigenous Protected and Conserved Areas across Canada. These protected areas can provide mitigation for cumulative effects, and demonstrate taking action to reduce cumulative effects beyond monitoring and assessing.
• Furthermore, the Government of Canada (including departments, agencies, and regulatory bodies) is required to consider cumulative effects under various laws, including those that define federal impact and environmental assessment processes. The nature and scope of cumulative effects considered varies depending on the specific statute. For example, under the Impact Assessment Act, the determination as to whether a project can proceed is informed in part by an assessment of cumulative effects, including the extent to which such effects can be mitigated and are significant.

The Government of Canada will continue to develop and implement a plan to explain and provide additional detail on how it will understand, consider and support the management of cumulative effects. This work may apply to, but not be limited to, activities undergoing federal impact and environmental assessment processes.

Jurisdiction over cumulative effects is shared among different levels of government. The Government of Canada will look to Indigenous peoples, governments, industry, stakeholders, and the public to contribute to enhancing our shared understanding, consideration, and management of cumulative effects.

The Government of Canada recognizes that the understanding, consideration, and management of cumulative effects is evolving across jurisdictions, and plans to evolve with it. In that context, it recognises that this work includes:

• Improving the identification and analysis of sources of cumulative effects and their relative contributions, as well as increasing transparency as to how this analysis is done and how it informs decisions.
• Improving consideration of Indigenous knowledge and the weaving of Indigenous knowledge with western science and data to understand more fully cumulative effects and their impacts to Indigenous rights and interests.
• Improving the coordination and collaboration across the Government of Canada and with other levels of government on cumulative effects.

There are many definitions of cumulative effects, varying across jurisdictions. For example:

• The Canadian Council of Ministers on the Environment developed the following definition in 2014: “cumulative effects are defined as the changes in the environment caused by multiple interactions among human activities and natural processes, which accumulate across time and space.”
• The Impact Assessment Agency of Canada states that “cumulative effects are defined as changes to the environment, health, social and economic conditions as a result of a project’s residual effects combined with the existence of other past, present and reasonably foreseeable physical activities.”
• The Province of British Columbia defines cumulative effects as “changes to environmental, social and economic values caused by the combined effect of past, present and potential future human activities and natural processes.”
• The Metlakatla Cumulative Effects Monitoring program defines cumulative effects as “changes to the environment or human well-being from past, present, and future development projects and human activities.”
• The Nunavut Impact Review Board in defines cumulative effects as “the accumulation of changes to the environment caused by human activities (for example, past, existing and proposed activities, including activities associated with the project under assessment). These changes occur over space and time and can be brought about by environmental effects that are additive or interactive. For example hunting, oil spills, and loss of habitat, commercial fishing pressure on prey species, can affect marine mammals in the Arctic.” 

Some definitions consider only cumulative environmental effects, while others also include cumulative socio-economic and health effects. Some definitions include only human activities, while other also include natural processes. Some focus on adverse effects, while others consider both positive and adverse effects. Generally, they all refer to effects that are individually minor, but collectively significant.

The following are examples of federal impact and environmental assessment processes:

• Impact assessment of designated projects under the Impact Assessment Act
• Carrying out regional assessments under the Impact Assessment Act
• Assessment of energy projects under the Canadian Energy Regulator Act
• Assessment of New Class 1 nuclear facilities and uranium mine and mill projects under the Nuclear Safety and Control Act

Many federal laws are relevant to understanding, considering, and supporting the management of cumulative effects. Here are some examples that include the terms “cumulative effects” or “cumulative impacts” (note the nature and scope of effects to be considered varies):

• Impact Assessment Act administered by the Impact Assessment Agency of Canada.

Assessments of potential cumulative effects to environment, socio-economic, and health conditions are required for all designated projects undergoing federal impact assessments under the Act; cumulative effects are taken into account when a final public interest decision is made. 

• Yukon Environmental and Socio-economic Assessment Act, Nunavut Planning and Project Assessment Act, and the Mackenzie Valley Resource Management Act, as administered by the Minister of Northern Affairs and federal responsible Ministers, in coordination with the territorial governments and First Nations.

Federal and territorial project decision-makers are required to consider the impact assessment report and recommendations, including the any assessment of cumulative impacts, when making final decisions on northern project reviews conducted under the Acts.

• Canadian Energy Regulator Act administered by the Canada Energy Regulator (CER)

As a lifecycle regulator, the CER is responsible for ensuring that federal energy projects within its jurisdiction are constructed, operated, and abandoned in a safe manner that protects people, property, and the environment. The CER considers a wide range of factors in project assessments including health, socio-economic, environmental, and cumulative environmental effects, and all potential impacts on the rights and interests of Indigenous peoples.

In the context of federal impact and environmental assessment processes, cumulative effects refer to the combined effects from past, present, and reasonably foreseeable future human activities and natural processes. They may consider environment, health, socio-economic conditions and other factors, and be informed by cumulative impacts on the rights and interests of Indigenous peoples.

Impacts on the rights and interests of Indigenous peoples may result from the impacts of past, existing and future activities. In the context of federal impact and environmental assessment processes, an assessment of cumulative impacts to the rights and interests of Indigenous peoples considers how cumulative effects alter the ability of Indigenous peoples to meaningfully exercise rights, protect interests, and carry out cultural practices. An assessment of cumulative impacts on the rights and interests of Indigenous peoples is done with consideration of different factors than a cumulative effects assessment, with different geographic and temporal scopes, with different pathways and criteria. Cumulative impacts on the rights and interests of Indigenous peoples may have a regional or historic context and may extend to aspects of rights related to socio-economics, health, culture, heritage, and other matters tied to an Indigenous peoples’ history and connection to the landscape. An assessment of cumulative impacts on the rights and interests of Indigenous peoples is meant to enable an understanding of the existing state of affairs and the complex history of interconnected effects on a holistic level.^{Footnote 4} 

Consider this plastic bottle, a single ocean wave, or this small drip of oil from a vehicle.

Individually, these aren’t usually a big deal. But they can add up, over and over and over.

They contribute to what we call cumulative effects, and they can negatively affect ecosystems, communities, health and economies.

In the same way that a path becomes worn when people use it over and over, cumulative effects add more and more stress to ecosystems, even if that’s over years or decades.

Some of these stressors are natural, and some are caused by human activity and development.

Let’s look at water quality as an example.

Effluent from a variety of industrial sites and activities.

The clearing of land, contributing to erosion and silty water from extreme rainfall.

Pesticides, fertilizers and organic waste, and sediment coming from farms, golf courses, and gardens.

Pollutants from urban runoff, like oil and gas, that might have spilled or dripped on the road.

All these things can add up and interact with each other, cumulatively, to lower the quality of our water and compromise the habitats of species that rely on that water, like fish and birds.

The same kinds of things can happen to air quality through vehicle and industrial exhaust, chimneys, fertilizers and forest fires.

And wildlife habitat can be stressed by forestry, urban encroachment, pipeline construction, transmission lines, new roads, and more.

Sometimes quickly, sometimes slowly, but very surely, these stressors take their toll. They can result in loss of habitat for wildlife, affect wetlands for waterfowl, increase air pollution and possibly affect human health.

Over time, all these stressors put sustained pressure on ecosystems and the health of species that inhabit them, including us.

By monitoring, studying, mitigating, and collaborating with others, we are working to understand and manage cumulative effects.

And you can be part of the solution too. So next time you think one plastic bottle, or a drip of oil, isn’t a big deal, think about the impact of this happening 1,000 times, 1,000,000 times. It all adds up.

Every action counts. The choices we all make matter!