If you look at a thermal image of a city
and then compare that to a map of vegetation,
you'll find that where there's greenery,
the temperature is lower.
That's because things like
asphalt, concrete and shingled roofs
absorb more heat from the sun than trees.
This is the urban heat island effect,
and it accounts for the higher temperatures in cities,
often by several degrees
compared with their surroundings.
It's becoming a huge risk to human health
as growing urban populations exacerbate
the heating effects of climate change.
Heat waves kill more people
than any other extreme weather event,
more than tornadoes, hurricanes and even floods.
That's why urban heat island mitigation strategies
are being studied in Singapore
by a group of researchers.
The government-backed project
called Cooling Singapore
is now in the process of combining
everything they've learned
to create a digital tool
that can help cities all over the world,
starting with Singapore.
In Singapore, close to the equator,
temperatures regularly rise above
32 degrees Celsius or 90 degrees Fahrenheit.
And the city structures only make it worse.
And that is also the case for Singapore,
which is basically a concrete jungle,
more urbanized, more developed city.
And even in Singapore,
what you have is a situation whereby
there's a temperature difference
of 7 degrees Celsius
between the more urbanized and the more rural areas.
The government has taken drastic steps
to keep temperatures down.
This is Gardens by the Bay,
an award-winning park.
And inside this greenhouse
it's a pleasant 24 degrees.
That's because the dome,
along with two dozen nearby towers
full of thousands of people,
is chilled by what's probably the world's
largest underground district cooling system.
It uses a large central plant
that cools water
and then pipes it into banks,
residential towers,
an exhibition center,
shopping malls
and the city's iconic Marina Bay Sands hotel
and casino complex.
So one of the biggest perks of using this system
for the buildings is that
they can save 40% in terms of electricity usage
compared to your traditional air conditioners.
And with Singapore relying on natural gas
for most of its power,
this new system means emissions
savings equivalent to removing 10,000 cars
from the city's roads.
That has big implications for the rest of the world.
If things stay as they are,
more than a third of the world's electricity
could end up being used to cool
buildings and vehicles by 2050.
As the world gets hotter, gets warmer,
there is a greater need for air conditioning
and as well as refrigerators, for instance.
And the more people are buying
these household appliances,
the more energy usage they use
and they release heat more,
and that then exacerbates climate change.
It's a vicious circle.
And so since 2017,
researchers at Cooling Singapore
have been identifying design solutions
that reduce our need for so much
cool air in the first place.
One thing many cities have in common,
and that's the importance of vegetation.
That's a very important measure
to mitigate the urban heat
because of the shading effect, of course,
and deep psychological effects of the vegetation.
And also because of the possible
evaporative cooling effect of the vegetation.
Vegetation can be, of course,
on the ground floor
in form of trees and shrubs.
And you can walk under them.
This is the so-called canopy layer
that the vegetation forms above us.
But vegetation can also go up
the facades of buildings
and it can go to the roof of the buildings.
Luckily, Singapore has been striving
for the Garden City feel for quite some time.
It was a vision initially introduced
by then Prime Minister Lee Kuan Yew in 1967
to make life more pleasant for people.
And today, Singapore is one of the world's
greenest cities in terms of urban vegetation.
Kampung Admiralty, a community center
that contains health facilities and social spaces,
now provides more green space
than the plot of land it was originally built on.
It's topped by a roofscape
of staggered terraces covered in local plants,
which functions as a community park,
and a village green in the center
that contains farm plots for residents to tend to.
Parkroyal on Pickering was designed
as a hotel in a garden
that doubled the green-growing potential of its site.
There's now 15,000 meters of sky gardens,
reflecting pools, waterfalls,
planter terraces and green walls.
And the government has big plans as well.
Singapore actually has a plan
to plant 1 million trees
and add more green spaces over the next 10 years.
It is actually a mix of one thing
to reduce the urban heat island effect.
But on the other hand,
it's also to to get the people
to be more connected to nature.
But it's not enough.
The city-state has still
been warming twice as quickly
as the world average
over the past six decades.
That's why Cooling Singapore has developed
a catalog of other potential
heat-mitigation measures.
When you try to mitigate
the urban heat island effect
in a city or in any building,
in a village as well,
the first place to start
is by shading of the windows.
You have to keep areas clear
so that the wind can move through it.
Water of a certain depth
can act as a very good thermal buffer.
If you have to construct heavy buildings,
such as high rises,
at least you can make the surface,
the facade less heavy.
And you can protect it from direct sun penetration.
We have to make sure that no combustion engines
will be in the city
in the middle,
in the medium- to long-term range.
So ideally, the electricity production
is outside of the city.
And you bring just the clean electricity
into the city.
You can at least minimize
the use of energy in the city.
And you can start to slowly convert the roofs,
the facades of the city,
into production areas for renewable energy.
In Singapore, unfortunately,
this is a limited option.
But in the long run,
it could produce up to 20%, 25% of the energy,
of the electricity needed in Singapore.
If all the roofs and the areas in the buildings,
on the buildings,
on the facades would be used to do that.
With so many different ideas,
Cooling Singapore is also designing
a virtual model of the city to test them out.
It's called a Digital Urban Climate Twin, or DUCT,
that will calculate how each element
of the city's design will impact
the urban heat island effect.
That means we model not only the geometry
of the buildings digitally,
but also we model the transportation,
the insulation, the temperature,
the radiation coming from the sun,
the weather, the local weather,
the local climate,
the even very, very microclimate of the city,
the water, the movement of people in the city.
We can invent scenarios.
We can design scenarios,
test them before we actually build them.
And if they test very well
and we are sure that they will function,
then we can start to build them
and put them into reality.
Singapore will be using this new tool
to figure out which actions it should take next.
And the model can be applied to any city,
whether it needs to keep heat out
or keep heat in,
which will ultimately save energy,
slow climate change
and improve our quality of life.
So this is something that Singapore
will be able to export,
maybe even together with its city development systems
that it already has.
Singapore is one of
the very few cities in the world
that really combined this scientific approach
with a very well-established urban redesign
and urban design approach.
Through its agencies
and the combination of its agencies,
it has achieved a lot in the past.
If it keeps following the scientific path
and the combination with
the other knowledge in the city already,
we think that it will be a very comfortable
and very livable city in the future,
even more than today.