Small parks could cool big cities

A LITTLE bit of greenery in urban areas can cool off the hotter and stickier summers that city residents face as a result of global warming, new research show.

An additional 10 per cent more green space could reduce surface temperatures by 7 degrees Fahrenheit, according to a team of British scientists. Extra parks and green roofs could counteract the predicted rise in temperature until 2080 when summers are expected to be hotter and drier and winters wetter.Because American cities are more prone than British cities to high summer temperatures, University of Manchester biologist Roland Ennos said green space has an even more important function in the United States.In cities around the world, planting more grass and trees could keep people more comfortable and reduce air conditioning costs and energy expenditures, Ennos said.”It should make life more pleasant climatically,” Ennos told LiveScience.”Many studies have also shown that it improves people’s physical and mental health, sense of wellbeing, and can result in reductions in crime.”The research, published in the current issue of the journal Built Environment, coincides with President Bill Clinton’s announcement last Wednesday that 15 cities, including New York and London, will update city-owned buildings with energy-efficient technology to cut carbon emissions.On sunny days, urban areas such as downtown sections of American cities can be up to 22 degrees Fahrenheit hotter than more rural areas.But the research team found that adding green space can minimise the “urban heat island” effect, which involves the fact that plants collect and retain water more efficiently than skyscrapers and parking lots.When the water evaporates from leaves on plants and trees, it cools off the air nearby, just like evaporating sweat cools us down.Floods could be prevented with more rainwater storage, Ennos said, which might keep the city’s green space irrigated during the droughts expected in summer months.LiveScienceExtra parks and green roofs could counteract the predicted rise in temperature until 2080 when summers are expected to be hotter and drier and winters wetter.Because American cities are more prone than British cities to high summer temperatures, University of Manchester biologist Roland Ennos said green space has an even more important function in the United States.In cities around the world, planting more grass and trees could keep people more comfortable and reduce air conditioning costs and energy expenditures, Ennos said.”It should make life more pleasant climatically,” Ennos told LiveScience.”Many studies have also shown that it improves people’s physical and mental health, sense of wellbeing, and can result in reductions in crime.”The research, published in the current issue of the journal Built Environment, coincides with President Bill Clinton’s announcement last Wednesday that 15 cities, including New York and London, will update city-owned buildings with energy-efficient technology to cut carbon emissions.On sunny days, urban areas such as downtown sections of American cities can be up to 22 degrees Fahrenheit hotter than more rural areas.But the research team found that adding green space can minimise the “urban heat island” effect, which involves the fact that plants collect and retain water more efficiently than skyscrapers and parking lots.When the water evaporates from leaves on plants and trees, it cools off the air nearby, just like evaporating sweat cools us down.Floods could be prevented with more rainwater storage, Ennos said, which might keep the city’s green space irrigated during the droughts expected in summer months.LiveScience