Mapping an urban ecosystem service: quantifying above-ground carbon storage at a city-wide scale

1. Despite urbanization being a major driver of land-use change globally, there have been few attempts to quantify and map ecosystem service provision at a city-wide scale. One service that is an increasingly important feature of climate change mitigation policies, and with other potential benefits, is biological carbon storage. 2. We examine the quantities and spatial patterns of above-ground carbon stored in a typical British city, Leicester, by surveying vegetation across the entire urban area. We also consider how carbon density differs in domestic gardens, indicative of bottom-up management of private green spaces by householders, and public land, representing top-down landscape policies by local authorities. Finally, we compare a national ecosystem service map with the estimated quantity and distribution of above-ground carbon within our study city. 3. An estimated 231 521 tonnes of carbon is stored within the above-ground vegetation of Leicester, equating to 3.16 kg C m(-2) of urban area, with 97.3% of this carbon pool being associated with trees rather than herbaceous and woody vegetation. 4. Domestic gardens store just 0.76 kg C m(-2), which is not significantly different from herbaceous vegetation landcover (0.14 kg C m(-2)). The greatest above-ground carbon density is 28.86 kg C m(-2), which is associated with areas of tree cover on publicly owned/managed sites. 5. Current national estimates of this ecosystem service undervalue Leicester's contribution by an order of magnitude. 6. Synthesis and applications. The UK government has recently set a target of an 80% reduction in greenhouse gas emissions, from 1990 levels, by 2050. Local authorities are central to national efforts to cut carbon emissions, although the reductions required at city-wide scales are yet to be set. This has led to a need for reliable data to help establish and underpin realistic carbon emission targets and reduction trajectories, along with acceptable and robust policies for meeting these goals. Here, we illustrate the potential benefits of accounting for, mapping and appropriately managing above-ground vegetation carbon stores, even within a typical densely urbanized European city

From refuge to refugee : the African case

iii, 19 p.In 1994, the United Nations introduced the concept of human security, predicating it on the dual notion of safety from chronic threats of hunger, disease, and repression on the one hand and protection from sudden and hurtful disruptions in daily life on the other. Such thinking helped foster the notion of "environmental refugee" to describe a new insight into an old phenomenon: large numbers of the world's least secure people seeking refuge from insecure biophysical environments. Yet, it can be misleading to assume that reducing environmental insecurity will avail more human security and, by extension, result in fewer environmental refugees. Under certain circumstances, more environmental security can generate a category of environmental refugees little noticed by those who have popularized this term. This paper concerns itself with the significant threat caused to human populations by exclusionary conservation. We begin by characterizing the human insecurity linked to increasing environmental security via protected area conservation, as a variant of environmental refugeeism. Using a combination of land use change and case study approaches, we estimate the number of Africans experiencing this phenomenon. We then place environmental refugeeism in the context of recent economic development theory and suggest why "environmental refugees" are in double jeopardy. That is, they often undergo a series of dislocations resulting from development initiatives, one form of which is protected area greenlining. We conclude with a discussion of one possible remedy for policy administrators seeking expanded conservation and a reduction in human displacement