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Abstract Background This review updates a systematic review published in 2010 ( http://www.environmentalevidence.org/completed-reviews/how-effective-is-greening-of-urban-areas-in-reducing-human-exposure-to-ground-level-ozone-concentrations-uv-exposure-and-the-urban-heat-island-effect ) which addressed the question: How effective is ‘greening’ of urban areas in reducing human exposure to ground-level ozone concentrations, UV exposure and the ‘urban heat island effect’? Methods Searches of multiple databases and journals for relevant published articles and grey literature were conducted. Organisational websites were searched for unpublished articles. Eligibility criteria were applied at title, abstract and full text and included studies were critically appraised. Consistency checks of these processes were undertaken. Pre-defined data items were extracted from included studies. Quantitative synthesis was performed through meta-analysis and narrative synthesis was undertaken. Review findings 308 studies were included in this review. Studies were spread across all continents and climate zones except polar but were mainly concentrated in Europe and temperate regions. Most studies reported on the impact of urban greening on temperature with fewer studies reporting data on ground-level UV radiation, ozone concentrations (or precursors) or public health indicators. The findings of the original review were confirmed; urban green areas tended to be cooler than urban non-green areas. Air temperature under trees was on average 0.8 °C cooler but treed areas could be warmer at night. Cooling effect showed tree species variation. Tree canopy shading was a significant effect modifier associated with attenuation of solar radiation during the day. Urban forests were on average 1.6 °C cooler than comparator areas. Treed areas and parks and gardens were associated with improved human thermal comfort. Park or garden cooling effect was on average 0.8 °C and trees were a significant influence on this during the day. Park or garden cooling effect extended up to 1.25 kms beyond their boundaries. Grassy areas were cooler than non-green comparators, both during daytime and at night, by on average 0.6 °C. Green roofs and walls showed surface temperature cooling effect (2 and 1.8 °C on average respectively) which was influenced by substrate water content, plant density and cover. Ground-level concentrations of nitrogen oxides were on average lower by 1.0 standard deviation units in green areas, with tree species variation in removal of these pollutants and emission of biogenic volatile organic compounds (precursors of ozone). No clear impact of green areas on ground level ozone concentrations was identified. Conclusions Design of urban green areas may need to strike a balance between maximising tree canopy shading for day-time thermal comfort and enabling night-time cooling from open grassy areas. Choice of tree species needs to be guided by evapotranspiration potential, removal of nitrogen oxides and emission of biogenic volatile organic compounds. Choice of plant species and substrate composition for green roofs and walls needs to be tailored to local thermal comfort needs for optimal effect. Future research should, using robust study design, address identified evidence gaps and evaluate optimal design of urban green areas for specific circumstances, such as mitigating day or night-time urban heat island effect, availability of sustainable irrigation or optimal density and distribution of green areas. Future evidence synthesis should focus on optimal design of urban green areas for public health benefit.

Essential Biodiversity Variables (EBVs) are measurements required for study, reporting, and management of biodiversity change. They are being developed to support consistency, from the collection to the reporting of biodiversity data at the national, regional and global scales. However, "EBV stakeholders" need to strike a balance between 'doing innovative research' and 'having positive impact' on biodiversity management decisions. This paper reports on a workshop entitled Identifying joint pathways to address the challenges of biodiversity data provision and decision-making and presents the main workshop’s output, a “researcher’s brief” entitled Guiding principles for promoting the application of EBVs for current and future needs of decision-makers. These guiding principles are: Speak with a common voice; Clearly define what is an EBV and how it relates to indicators; Engage beyond the research world; Be realistic about what can be done now and later; Define criteria for good EBVs; Use EBV as a clearing house; Convey the limitations of EBVs; Clarify what impact EBVs should have; Be salient, credible, legitimate, iterative; Don't put an EBV skin on everything you do; Don't create too many EBVs; and Don't reduce EBVs to building blocks of indicators. This brief is of relevance to the wider GEO BON (Group on Earth Observation Biodoversity Observation Network) community, and in particular those scientists/researchers interested in the application of EBVs.

Abstract Background The impact of climate change on public health may occur through a number of main pathways including increased temperature, ground-level ozone levels and ultra-violet radiation, which have a range of consequences for human health. One strategy for adaptation to the predicted effects of climate change on health that has been proposed, is to ‘green’ urban areas, essentially by increasing the abundance and cover of vegetation. This protocol is for an update of a systematic review which aimed to address the question: How effective is ‘greening’ of urban areas in reducing human exposure to ground-level ozone concentrations, UV exposure and the ‘urban heat island effect’? Methods A sensitive search of multiple databases and relevant journals for relevant published articles will be conducted. A search for relevant unpublished articles will be undertaken through an internet search and of websites of relevant organisations. Inclusion criteria will be applied at title, abstract and full-text. Repeatability checks of this screening process will be undertaken. Articles included at full-text will be critically appraised using a standardised checklist. A repeatability check will be made of this process. Pre-defined data items will be extracted from included articles. If appropriate, quantitative synthesis will be undertaken through meta-analysis and/or a narrative synthesis will be undertaken.

Climate change indicators are tools to assess, visualize and communicate the impacts of climate change on species and communities. Indicators that can be applied to different taxa are particularly useful because they allow comparative analysis to identify which kinds of species are being more affected. A general prediction, supported by empirical data, is that the abundance of warm-adapted species should increase over time, relative to the cool-adapted ones within communities, under increasing ambient temperatures. The community temperature index (CTI) is a community weighted mean of species' temperature preferences and has been used as an indicator to summarize this temporal shift. The CTI has the advantages of being a simple and generalizable indicator; however, a core problem is that temporal trends in the CTI may not only reflect changes in temperature. This is because species' temperature preferences often covary with other species attributes, and these other attributes may affect species response to other environmental drivers. Here, we propose a novel model-based approach that separates the effects of temperature preference from the effects of other species attributes on species' abundances and subsequently on the CTI. Using long-term population data of breeding birds in Denmark and demersal marine fish in the southeastern North Sea, we find differences in CTI trends with the original approach and our model-based approach, which may affect interpretation of climate change impacts. We suggest that our method can be used to test the robustness of CTI trends to the possible effects of other drivers of change, apart from climate change.