Several important considerations should be made when humans undertake activities that could significantly impact natural ecosystems and cycles:
• Unintended consequences. Natural systems are complex with many interconnected cycles and relationships. Impacting one part of the system could have unintended ripple effects that disrupt other parts of the system in unforeseen ways. This could undermine the intended benefits or create new problems.
• Resilience and feedbacks. Natural ecosystems have evolved resilience to adapt to disturbances, but there are limits to their resilience. Large enough impacts could push a system past a tipping point into a new, less desirable state. Negative feedback mechanisms could also amplify the impacts.
• Cumulative effects. Small individual impacts may seem insignificant but could accumulate over time into something that overtakes the ability of a system to cope. This is especially true for repetitive or ongoing activities.
• Alternative options. There may be alternative approaches that could achieve the goals without as much ecological disruption or impact. Considering alternatives is important before making a major change.
• Reversibility. Some impacts, like species extinctions, are essentially irreversible on human timescales. Other impacts may be reversible if stopped, but reversing them could be difficult and have high costs. The reversibility of any changes should be evaluated.
• Fairness of burdens and benefits. The costs of environmental impacts often accrue locally while the benefits may be spread more broadly. Environmental justice requires considering who bears the burdens of impacts versus who benefits.
• Precaution. When crucial aspects of natural systems are at stake and impacts could be irreversible, it is prudent to err on the side of caution. The precautionary principle suggests avoiding even plausibly harmful actions when the full consequences are uncertain.
• Long time horizons. Human lifespans and political cycles are short compared to the timescales of natural ecological processes. Impacts and their consequences need to be evaluated based on long time horizons of hundreds to thousands of years. Short-term thinking could undermine long-term sustainability.