Assessments bring together diverse strands of knowledge in a way that is useful for decision making. Assessments are key mechanisms through which science informs decision making. UNEP undertakes, supports and is a partner in a number of environmental assessments with different thematic and geographic coverage.

Assessments are fundamentally communication processes, not simply reports, which share many similar features, regardless of their scope. The following characteristics define an environmental assessment

• It is a critical, peer-reviewed evaluation of information, for purposes of guiding decisions on a complex public issue, following a well-defined process.
• The scope (topic) is defined by multiple stakeholders, typically decision makers. Findings are policy-relevant but not prescriptive.
• Conducted by a credible group of experts with a broad range of disciplinary and geographical expertise, in a balanced and transparent manner.

DEWA also undertakes extensive review of the latest science on specific issues to identify consensus by sorting out what is known and widely accepted from what is known and not agreed. Such issues are highlighted in the UNEP Year Book series, the Climate Change Compendium report and in the early warning work of emerging issues that DEWA undertakes.