Cities prove greener than the countryside

Cities emit less carbon on a per-capita basis than their rural counterparts, according to a new study of US metropolitan areas from the Brookings Institution.

The report, Shrinking the Footprint of Urban America, found that the top 100 metropolitan areas in the US produced 56 per cent of the nation's carbon dioxide emissions, but housed two thirds of the population and three quarters of its economic activity.

The disparity in carbon emissions was due largely to reduced car travel in metropolitan areas, along with reduced residential electricity usage.

City carbon emissions are also growing more slowly than in other areas. Between 2000 and 2005, emissions in the top 100 metro areas grew by 6.3 per cent compared with a 9.1 per cent average. This equates to a per-capital footprint growth of just 1.1 per cent in metropolitan areas - half the national per-capita growth rate.

The non-profit public policy thinktank, which conducted the study as part of a broader scheme for urban redevelopment called Blueprint for Prosperity, called for federal action to help further reduce the footprint of metropolitan areas. Applying a price to carbon, stepping up federal R&D investment in cleantech, establishing a renewable energy standard, and creating state-level incentives for renewable energy were imperatives, it said. Federal initiatives to provide better data on greenhouse gas emissions would also help.

"Policy impediments include a bias against public transit, inadequate federal leadership on freight and land-use planning, failure to encourage energy- and location-efficient housing decisions, and the fragmentation of federal transportation, housing, energy, and environmental policies," said the Institute.

The west fared better than the south in carbon emissions across the US, managing to reduce its partial carbon footprint between 2000 and 2005. The south had the highest footprint in transport and residential carbon emissions.

The findings further highlight the extent to which opting for urban locations and developing integrated travel plans can help firms and developers curb carbon emissions.