Planetary stewardship in an urbanizing world: beyond city limits

Cities are rapidly increasing in importance as a major factor shaping the Earth system, and as such must take corresponding responsibility. With currently over half of the world population, cities are supported by resources originating from primarily rural regions that are often located around the world far distant from the urban loci of use. The multiple and complex environmental and social challenges the world faces require interconnected solutions and a coordinated governance approach to planetary stewardship. There is a new opportunity to conceptualize a key component of planetary stewardship as a global system of cities that develop sustainable processes and policies in concert with its non-urban areas. The potential for cities to cooperate as a system and with rural connectivity could not only increase their capacity to effect change and foster stewardship at the planetary scale but also increase their resource security

Monitoring the effect of urban green areas on the heat island in Athens

The role of urban green areas in the microclimatic conditions of cities, during summer, is investigated in this paper through monitoring campaigns carried out at the National garden, at the city centre of Athens. Two types of investigations were carried out: i) a microscopic one that investigated the thermal conditions inside the Garden and the immediate surrounding urban area and ii) a macroscopic one that compared the temperature profile of the Garden with that of the greater city centre area. It was concluded that in microscopic level, the temperature profile inside the National Garden and the immediate surrounding urban area did not showed a clear evidence of the influence of the Garden and it was dependent on the characteristics of each location. In a macroscopic scale, the Garden was found cooler than the other monitored urban locations and temperature differences were mainly greater during the night, especially in streets with high building height to street width (H/W) ratio and low traffic, while in streets with high anthropogenic heat during the day, the biggest temperature differences were recorded during the day