The explosion in the number of people living in cities is damaging the environment.

At a recent meeting of the Natural Environment Research Council's atmospheric science community, scientists tabled a research proposal to help cities recover from neglect and create sustainable and attractive urban environments.

The proposal, if successful, will form part of NERC's long-term strategy to deal with the key environmental challenges of the next two decades. It will involve collaboration between scientists at a host of institutions including the universities of Birmingham and Reading and Imperial College, London.

Scientists responsible for compiling the urban regeneration and the environment research (URGENT) bid note that in the United Kingdom 90 per cent of people live in conurbations which cover only 10 per cent of its land area. This concentration has global parallels. By 2000 it is estimated that half the world's six billion people will live in cities. "A major challenge in Britain and beyond will be to renew and develop cleaner and more sustainable urban environments in a way which contributes to social well being and economic prosperity," says NERC.

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Key problems that have resulted from the cultural legacy of industrialisation include the presence of large areas of contaminated land, which drive new industries into "greenfield" sites. Little consideration is given to land recycling strategies. There are also problems associated with hydrologically inefficient and polluted water courses, declining air quality due to car emissions and the destruction of the rich ecology that often flourishes in urban environments.

NERC scientists believe that the reclamation, reshaping and management of the urban environment requires coordinated action by local and national authorities, industry, commerce and private individuals. Their success will depend heavily on the work of scientists in areas such as the behaviour in the ground of toxic pollutants, the development of clean-up technologies and atmospheric activity over urban areas.

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Researchers will also need to survey and monitor for environmental factors such as ground undermining, the prevailing hydrological regime, flood pathways and water quality and ecological adaptation. NERC researchers are proposing surveys focusing on two major conurbations: London and the lower Thames and the Liverpool-Manchester corridor. The fruits of the research could well find application in many other countries especially those on the continent.

Another research project proposed by NERC scientists covers atmospheric modelling. A key player would be the Universities Global Atmospheric Modelling Programme set up by NERC in 1990, which links up leading atmosphere scientists in Britain. Institutions likely to take part include the centre for global atmospheric modelling at Reading University, the atmospheric chemistry modelling support unit at Cambridge University, the Institute of Hydrology and the Meteorological Office.

One of the proposed themes covers natural variability of the climate system, and aims to build on work established by UGAMP. Scientists know that the climate system of the troposphere and middle atmosphere exhibits natural and extensive variability over space and time. But they would like to deepen their understanding of this variability with the help of modelling. This could help them to make more informed pronouncements on the nature, scale and characteristics of environmental change and allow them to distinguish more clearly, between changes caused naturally and those caused by humans.

In the past UGAMP's work has focused on "atmosphere-only" models but scientists now believe they have substantial evidence indicating that many phenomena associated with climate variability depend on an intimate coupling between atmosphere and ocean. The new project would therefore aim to strengthen the atmosphere-only models with simulations of the coupled atmosphere-ocean system.

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The second theme the atmospheric modellers want to cover is modelling variability and predicting change in the behaviour of chemicals in the atmosphere.

NERC says that scientists already have a good understanding of chemical processes at polar latitudes, but their understanding of ozone loss at mid-latitudes is weak. A major programme of modelling and data analysis is therefore required, focusing on chemical and transport processes at middle latitudes in the lower stratosphere. Researchers want to relate this to the regimes in other regions of the atmosphere. Other aspects of the project would include how the troposphere removes ozone depleting and greenhouse gases and developing climate models that incorporate the impact of aerosols in the atmosphere.