Carbon dioxide balance assessment of the city of Florence (Italy), and implications for urban planning

The carbon dioxide balance for the Municipality of Florence (102.3 km2), with 29.1 km2 of green space within the built-up city and 46.6 km2 in the semi-rural peri-urban area, shows that collectively the green spaces offset 6.2% of the direct carbon emissions. However the green spaces in the densely built-up city only offset 1.1% of the emissions. 13.5 ktCO2 y−1 are taken up by vegetation in the built-up areas and 58.7 ktCO2 y−1 by vegetation in the peri-urban area. Urban green spaces are most efficient in offsetting anthropogenic CO2 emissions during the period March to June when plant growth rates are high and emission rates are relatively low. Landscape fragmentation is highly positively correlated with total CO2 emissions and negatively correlated with CO2 uptake. The detailed information produced during this investigation shows that policies aimed at reducing CO2 emissions in winter months will have a greater overall effect on total CO2 release to the atmosphere than those aimed at increasing CO2 uptake. Nevertheless, urban designers should consider all the benefits of urban green spaces and seek to ensure that new suburban development conserves green spaces and aims at sustainable urban design.