Systems integration for global sustainability

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Science  27 Feb 2015:
Vol. 347, Issue 6225, 1258832
DOI: 10.1126/science.1258832

Seeking systems-based solutions

Without sustainable solutions, the world's most pressing environmental concerns will continue to persist or worsen. Achieving the goal of sustainability involves so many factors—from economics to ecology—that investigating one or even a handful of variables at a time often overlooks major parts of the problem. Liu et al. review systems-based approaches that are beginning to provide tenable ways to assess sustainability. Further integrating coupled human and natural components of a problem across multiple dimensions, including how one solution can create unintended consequences elsewhere, is essential for developing effective policies that seek global sustainability.

Science, this issue 10.1126/science.1258832

Structured Abstract


Many key global sustainability challenges are closely intertwined (examples are provided in the figure). These challenges include air pollution, biodiversity loss, climate change, energy and food security, disease spread, species invasion, and water shortages and pollution. They are interconnected across three dimensions (organizational levels, space, and time) but are often separately studied and managed. Systems integration—holistic approaches to integrating various components of coupled human and natural systems (for example, social-ecological systems and human-environment systems) across all dimensions—is necessary to address complex interconnections and identify effective solutions to sustainability challenges.


One major advance has been recognizing Earth as a large, coupled human and natural system consisting of many smaller coupled systems linked through flows of information, matter, and energy and evolving through time as a set of interconnected complex adaptive systems. A number of influential integrated frameworks (such as ecosystem services, environmental footprints, human-nature nexus, planetary boundaries, and telecoupling) and tools for systems integration have been developed and tested through interdisciplinary and transdisciplinary inquiries. Systems integration has led to fundamental discoveries and sustainability actions that are not possible by using conventional disciplinary, reductionist, and compartmentalized approaches. These include findings on emergent properties and complexity; interconnections among multiple key issues (such as air, climate, energy, food, land, and water); assessment of multiple, often conflicting, objectives; and synergistic interactions in which, for example, economic efficiency can be enhanced while environmental impacts are mitigated. In addition, systems integration allows for clarification and reassignment of environmental responsibilities (for example, among producers, consumers, and traders); mediation of trade-offs and enhancement of synergies; reduction of conflicts; and design of harmonious conservation and development policies and practices.


Although some studies have recognized spillover effects (effects spilling over from interactions among other systems) or spatial externalities, there is a need to simultaneously consider socioeconomic and environmental effects rather than considering them separately. Furthermore, identifying causes, agents, and flows behind the spillover effects can help us to understand better and hence manage the effects across multiple systems and scales. Integrating spillover systems with sending and receiving systems through network analysis and other advanced analytical methods can uncover hidden interrelationships and lead to important insights. Human-nature feedbacks, including spatial feedbacks (such as those among sending, receiving, and spillover systems), are the core elements of coupled systems and thus are likely to play important roles in global sustainability. Systems integration for global sustainability is poised for more rapid development, and transformative changes aimed at connecting disciplinary silos are needed to sustain an increasingly telecoupled world.

Illustrative representation of systems integration.

Among Brazil, China, the Caribbean, and the Sahara Desert in Africa, there are complex human-nature interactions across space, time, and organizational levels. Deforestation in Brazil due to soybean production provides food for people and livestock in China. Food trade between Brazil and China also contributes to changes in the global food market, which affects other areas around the world, including the Caribbean and Africa, that also engage in trade with China and Brazil. Dust particles from the Sahara Desert in Africa—aggravated by agricultural practices—travel via the air to the Caribbean, where they contribute to the decline in coral reefs and soil fertility and increase asthma rates. These in turn affect China and Brazil, which have both invested heavily in Caribbean tourism, infrastructure, and transportation. Nutrient-rich dust from Africa also reaches Brazil, where it improves forest productivity. [Photo credits clockwise from right top photo: Caitlin Jacobs, Brandon Prince, Rhett Butler, and David Burdick, used with permission]


Global sustainability challenges, from maintaining biodiversity to providing clean air and water, are closely interconnected yet often separately studied and managed. Systems integration—holistic approaches to integrating various components of coupled human and natural systems—is critical to understand socioeconomic and environmental interconnections and to create sustainability solutions. Recent advances include the development and quantification of integrated frameworks that incorporate ecosystem services, environmental footprints, planetary boundaries, human-nature nexuses, and telecoupling. Although systems integration has led to fundamental discoveries and practical applications, further efforts are needed to incorporate more human and natural components simultaneously, quantify spillover systems and feedbacks, integrate multiple spatial and temporal scales, develop new tools, and translate findings into policy and practice. Such efforts can help address important knowledge gaps, link seemingly unconnected challenges, and inform policy and management decisions.

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