Every day, people around the world move from rural
areas to the city in search of work and a better life. Cities offer unique
opportunities, but risks as well. In hot countries, these include the deadly
threats of urban heat and air pollution.
High rise buildings and paved roads trap heat, raising temperatures and
creating urban heat islands. These heat islands don’t just threaten people’s
health – they encourage people to use energy-intensive air conditioning,
potentially driving more global warming. Clever planning can help cool our cities and clean our air. And bodies of water – from rivers and canals to urban mangroves – have a big role to play. Here’s why.
Floating wetlands and freshwater mangroves
Firstly, bodies of water absorb heat. But they also support another great
cooling solution – greenery. Trees, bushes and plants cool the air by giving
shade and absorb and reflecting heat.
In Singapore the Punggol Waterway project, which opened to the public in 2011,
has created an artificial river at the heart of a large residential
development. The waterway features ‘floating wetlands’ – interlocking hexagons planted
with a range of wetland species. And the banks of the waterway are lined with
freshwater mangroves, adding more vegetation to the community.
Medellin, once the world’s most dangerous city, has over 30 Green Corridors
that heal and cool. Lining the cities roads and waterways are vast planting
projects providing shade and cleaning the air in residential areas. Streams and
waterways connect three of the main hills in the city, providing the irrigation
that keeps Medellin green.
26 Jun | News
Cooling by Nature: An Urban Greening Award
With cities swelling and temperatures rising, the world urgently needs more urban
cooling solutions. That’s why this year’s Ashden Awards feature an urban cooling Award, sponsored by Climateworks K-CEP, for the very first time. The Punggol and Medellin schemes are
on the longlist, along with a landscaping for urban spaces and high-rises
project run by Singapore’s urban redevelopment authority, and a public space
greening programme in the Ethiopian capital Addis Ababa.
Waterways can tackle a host of urban sustainability challenges beyond dangerous
heat. One is air pollution, which causes 1 in 9 deaths worldwide. Fumes from
cars and other vehicles are a major factor, and residents of our crowded cities
are most at risk.
Waterways support vegetation that cleans the air – but they are also an ideal
place for planners to introduce new footpaths and bike tracks, helping people
swap polluting cars for cleaner transport. Paths and cycle lanes run alongside
Medellin’s waterways – while the Punggol development includes a 9km coastal
promenade, as well as generous walking space along the side of the waterway
We look forward to announcing our first urban cooling winner at the 2019 Ashden Awards on July 3. Forwards-thinking innovators, like those on our longlist, can help turn a trickle of bright ideas into a flood.