Review of the U.S. Climate Change Science Program's Synthesis and Assessment Product 3.2, "Climate Projections Based on Emission Scenarios for Long-lived and Short-lived Radiatively Active Gases and Aerosols" (2007)

The committee notes several stylistic issues, which, if addressed, could significantly improve the overall accessibility of the document for a wider audience and improve the coherence of the document. Specific instances will be noted in the sections of this report that provide reviews of individual chapters of the draft. Broadly, these issues are:

• Jargon and definitions: The language suffers from excessive use of jargon and a lack of definitions of terms that may have multiple meanings to multiple readers. For example, certain terms such as, “very likely”, and “likely” are used with the “specific IPCC connotations”. These connotations should be defined, or the text translated so that they are accessible to the non-technical reader, particularly in the “key findings”. In addition, the authors should expand the glossary for less commonly understood terms and phrases.

• Acronyms: There are many instances in which undefined acronyms are used or defined at a later point. In general acronyms are over used to the point that they interfere with the flow of the document.

• Content arrangement: The document would be improved by relegating supporting text that is not central to the study to boxes. For example, the authors could consider revising Chapter 2 to focus more on the climate implications of emissions scenarios developed in SAP 2.1a, and move the summary of results of the IPCC WGI AR4 to a box.