Trees soaking up CO2 of city traffic

CARBON DIOXIDE generated by morning peak-time traffic in Dublin is soaked up by the city’s trees in early afternoon, an international…

CARBON DIOXIDE generated by morning peak-time traffic in Dublin is soaked up by the city’s trees in early afternoon, an international conference of urban climatologists heard this week.

The phenomenon has been confirmed within the past few weeks by an urban observation site at Dublin Institute of Technology (DIT), Kevin Street, set up in collaboration with UCD and NUI Maynooth.

“The site will make precise measurements of the atmosphere as modified by the city,” according to Dr Gerald Mills, senior lecturer at UCD’s school of geography, planning and environmental policy.

These include an examination of the “urban heat island” effect, which can magnify CO2 emissions, and the development of a detailed urban database to run a weather research forecasting model.

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A graph of the “heartbeat” of Dublin in terms of measured CO2 emissions in the city showed the morning peak clearly evident “as is the consumption of CO2 by trees in the early afternoon”, Dr Mills said.

“Large peaks in CO2 can be seen in the morning time, coinciding with the morning rush hour; this pattern is less evident at weekends when traffic flow is reduced”, researchers from the three colleges found.

CO2 levels tend to be lower in summer as a result of “benign weather conditions” and lower fuel consumption, but higher in winter due to heating demands and reduced “carbon storage capacity” in trees.

The observation site on the roof of DIT Kevin Street “will be one of the few long-term urban climate sites globally”, Dr Mills said, adding that it would help in understanding the interaction of cities and CO2.

This weeks's conference (see icuc8.org) has attracted 450 meteorologists interested in air quality, climatologists interested in the contribution of cities to climate change and urban designers seeking to create better cities.

One of the keynote speakers yesterday was Dr Stephen Belcher, professor of meteorology at the University of Reading and head of the British Met Office’s Hadley Centre for climate research.

Frank McDonald

Frank McDonald

Frank McDonald, a contributor to The Irish Times, is the newspaper's former environment editor