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The Millennium Ecosystem Assessment

The Millennium Ecosystem Assessment
Pilot Analysis of Global Ecosystems | EarthTrends

Unless we use the knowledge we've gained to sustainably develop Earth's ecosystems, we risk inflicting ever greater damage on them with dire consequences for economic development and human well-being.

— from the foreword to World Resources 2000-2001

What does it take to manage ecosystems so that they regain or retain their resilience as well as their productivity? How much more degradation can they tolerate? And, ultimately, can we repair what we've degraded?

To answer these questions accurately, ecosystem managers and policy makers need current, comprehensive, and scientifically authenticated data about the condition and capacity of the ecosystems they administer, how they interact, and the full effects of resource extractions. Until 2000, no such database existed. In 1999 an international group of more than 100 environmental scientists joined together to determine exactly what information we do have, where the data gaps exist, and what methodologies for data gathering would best fill those gaps. They chose to examine the five ecosystems humans depend on most — agricultural, coastal, forest, freshwater, and grassland ecosystems. They amassed and evaluated all available data on a global scale about these five ecosystems in a project called the Pilot Analysis of Global Ecosystems (PAGE). The results of that study are published in World Resources 2000-2001, the companion volume to Earth on Edge. Though not a full assessment, the PAGE results are the most up to date, comprehensive set of data currently available on the condition of ecosystems. Those data are now also available online in a searchable database called EarthTrends at

PAGE serves as a precursor to a four-year multi-scale, integrated assessment of the world's ecosystem called The Millennium Ecosystem Assessment.

The Millennium Ecosystem Assessment (MA) is a multi-scale, integrated analysis and evaluation of the consequences of changes to Earth's ecosystems. The work, for the sake of human livelihoods today and in the future, is being undertaken by a diverse group of experts from the natural and social sciences, government agencies, non-governmental organizations, and the private sector. The MA seeks to improve management of the world's natural and managed ecosystems by providing peer-reviewed, policy-relevant scientific information about:

  • the condition of ecosystems,
  • consequences of ecosystem change, and
  • options for response.
The participants in the MA believe that an international assessment of the impact of changes to ecosystems, based on the goods and services they provide, will build a foundation for wise policy making. The MA's primary purpose is to provide information that will help meet the needs of government and private-sector decision makers. The information will be available to those decision makers and to the public. The MA will also attempt to build individual and institutional capacity to provide information. The assessment will span a four-year period beginning in April 2001.

What are ecosystem goods and services?

Ecosystem goods include food, fiber, timber and other raw building materials, genetic resources, and medicines. Ecosystem services include water purification, flood control, coastline stabilization, carbon sequestration, waste treatment, biodiversity conservation, soil generation, disease regulation, pollination, maintenance of air quality, and the provision of aesthetic and cultural benefits. The consequences of changes to these goods and services affect food security, human health, economic development, employment, and often have the most direct impact on the poor who are most directly dependent on ecosystem goods and services and most vulnerable to environmental catastrophes associated with ecosystems such as floods and landslides.

How is the Millennium Assessment different from other assessment activities?

The MA will be a first attempt to undertake a multi-scale, integrated analysis of ecosystems. A "multi-scale" assessment is an overall appraisal that includes component assessments undertaken at several different geographic scales. The MA will make assessments at all scales ranging from individual villages to geographic regions to the entire planet. The process will be designed so that the findings at any given scale are informed by assessment components undertaken at other scales.

The assessment is also integrated and multi-sectoral. It includes both ecological and economic analyses. It considers both the current state of the ecosystem and its future potential. The principal benefit of an integrated ecosystem assessment is that it provides a framework for examining the interlinkages and trade-offs among various goods and services. In single-sector assessments, opportunities to increase the aggregate benefits from the bundle of goods and services produced by an ecosystem are hidden. By looking at the production and condition of the entire array of services, trade-offs among various services become apparent. Two fundamental features of this unique assessment are:

  • The assessment is place-based. The fundamental unit of interest is the ecosystem itself. Factors influencing that system may be either local (e.g., farming) or remote (e.g., change in atmospheric CO2). Site-specific or "spatial" information can then be aggregated to analyze regional or global trends and processes.

  • The assessment is multi-sectoral. It provides information about a suite of factors, how they interact to influence the ecosystem, and how an entire array of goods and services is affected by changes in the ecosystem.
What is the expected outcome of the MA?

Although the benefits of a multi-scale, integrated assessment are clear, the approach is new, the methodologies need to be developed and tested, existing data and the findings of research must be assembled, and in many cases new data and information will be needed. By making science-based, peer-reviewed information more widely available and building the individual and institutional capacity to provide information, the MA will develop the scientific underpinning for a wide range of national and international efforts to address environment and development challenges. With proper management, an ecosystem can withstand significant pressures, including population growth, increased resource consumption, pollution, and overharvesting. Prudent and sustainable management of Earth's ecosystems is what the participants in the Millennium Ecosystem Assessment intend to bring about. To learn more about the Millennium Ecosystem Assessment, visit the web site at

Pilot Analysis of Global Ecosystems (PAGE) »

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