Globally, efforts are underway to reduce anthropogenic greenhouse gas emissions and to adapt to climate change impacts at the local level. However, there is a poor understanding of the relationship between city strategies on climate change mitigation and adaptation and the relevant policies at national and European level. This paper describes a comparative study and evaluation of cross-national policy. It reports the findings of studying the climate change strategies or plans from 200 European cities from Austria, Belgium, Estonia, Finland, France, Germany, Ireland, Italy, Netherlands, Spain and the United Kingdom. The study highlights the shared responsibility of global, European, national, regional and city policies. An interpretation and illustration of the influences from international and national networks and policy makers in stimulating the development of local strategies and actions is proposed. It was found that there is no archetypical way of planning for climate change, and multiple interests and motivations are inevitable. Our research warrants the need for a multi-scale approach to climate policy in the future, mainly ensuring sufficient capacity and resource to enable local authorities to plan and respond to their specific climate change agenda for maximising the management potentials for translating environmental challenges into opportunities.

The role of vegetation in mitigating the effects of PM(10) pollution has been highlighted as one potential benefit of urban greenspace. An integrated modelling approach is presented which utilises air dispersion (ADMS-Urban) and particulate interception (UFORE) to predict the PM(10) concentrations both before and after greenspace establishment, using a 10 x 10 km area of East London Green Grid (ELGG) as a case study. The corresponding health benefits, in terms of premature mortality and respiratory hospital admissions, as a result of the reduced exposure of the local population are also modelled. PM(10) capture from the scenario comprising 75% grassland, 20% sycamore maple (Acer pseudoplatanus L.) and 5% Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) was estimated to be 90.41 t yr(-1), equating to 0.009 t ha(-1) yr(-1) over the whole study area. The human health modelling estimated that 2 deaths and 2 hospital admissions would be averted per year.

As a Nature-Based Solution, urban forests deliver a number of environmental ecosystem services (EESs). To quantify these EESs, well-defined, reliable, quantifiable and stable indicators are needed. With literature analysis and expert knowledge gathered within COST Action FP1204 GreenInUrbs, we proposed a classification of urban forest EESs into three categories: (A) regulation of air, water, soil and climate; (B) provisioning of habitat quality; and (C) provisioning of other goods and services. Each category is divided into EES types: (a) amelioration of air quality; restoration of soil and water; amelioration of the microclimate; removal of CO₂ from the air; (b) provision of habitat for biodiversity; support for resilient urban ecosystems; provision of genetic diversity; and (c) provision of energy and nutrients; provision of grey infrastructure resilience. Each EES type provides one or more benefits. For each of these 12 benefits, we propose a set of indicators to be used when analyzing the impacts on the identified EESs. Around half of the 36 indicators are relevant to more than one single benefit, which highlights complex interrelationships. The indicators of wider applicability are tree and stand characteristics, followed by leaf physical traits and tree species composition. This knowledge is needed for the optimization of the EESs delivered by urban forests, now and in the future.