This paper analyses the effect of different emission metrics and metric values on timing and costs of greenhouse gas mitigation in least-cost emission pathways aimed at a forcing level of 3.5 W m−2 in 2100. Such an assessment is currently relevant in view of UNFCCC's decision to replace the values currently used. An emission metric determines the relative weights of non-CO2 greenhouse gases in obtaining CO2-equivalent emissions.

Governments need research and guidelines to help them to move towns and villages threatened by global warming, argue David López-Carr and Jessica Marter-Kenyon.

Transparent, consistent, and accurate national forest monitoring is required for successful implementation of reducing emissions from deforestation and forest degradation (REDD+) programs. Collecting baseline information on forest extent and rates of forest loss is a first step for national forest monitoring in support of REDD+. Peru, with the second largest extent of Amazon basin rainforest, has made significant progress in advancing its forest monitoring capabilities.