What if buildings were made of trees
Transcriber: Dian Pusparani
Reviewer: David DeRuwe
So five years ago,
I traveled for the first time
in my life to the Amazon,
and I landed in Alta Floresta
in the state of Mato Grosso in Brazil.
Alta Floresta means
“high forest” in Portuguese,
but unfortunately
there’s hardly any forest left.
It’s actually been replaced by cattle
grazing and further afield by soybeans.
At this point, I banned beef from my diet,
and I decided that I would devote
the rest of my career
to trying to protect
healthy standing forest.
My name is Mireille Perrin.
I work for the Good Energies Foundation.
It is a private, Swiss-based foundation
whose mission is to mitigate and reduce
poverty caused by climate change.
Over the past 20 years, I’ve worked
on climate and sustainability issues
across the world
from Sri Lanka to Pakistan,
from Indonesia to Brazil.
And one thing remains constant:
There are many ideas and many solutions
based on nature which could result
in carbon savings.
For example,
what if we could reduce greenhouse
gas emissions by building with wood?
It turns out that
the construction sector today
is a big emitter
of greenhouse gas emissions.
It produces nearly 40%
of total global greenhouse gas emissions.
That’s more than
the transportation sector.
Out of this 40%, 28% of the emissions
come from the energy that is used
to heat, light, and cool the buildings,
and another 11% comes
from the construction processes
but also the construction materials,
such as steel and cement.
The problem is that construction
is expanding rapidly,
and we know that they are projections
which say that basically
in the next 40 years,
we will roughly be adding,
in terms of construction and building,
a size roughly equal to the city of Paris
every single week for the next 40 years.
So this makes us wonder:
Is it possible for the construction sector
to lower its environmental footprint
or even to give back to the environment?
Well, it’s possible, and that’s exactly
what was happening about 50 years ago
when the buildings
were made of wood, of trees.
In fact, we know that the use
of concrete and steel increased rapidly
with the boom of skyscrapers
and the rapid urbanization.
But today we have new technologies
that allow us to build
multistory buildings with wood.
For example, we have a new
technology called cross-laminated timber,
which consists of different wood panels
which are glued at opposite angles.
And this is really driving
the mass timber movement today.
In fact, there’s a whole family
of different mass timber products,
which today are lighter, they’re stronger,
they are more attractive,
and they are even more fire resistant
than concrete and steel.
So where does this take us?
In fact, it may seem counterintuitive
in terms of fighting the climate crisis,
but an increased demand for wood
and increased wood in buildings
doesn’t necessarily have to result
in increased deforestation
and emissions from land use change.
In fact, if you look at the past
15 years in the northern hemisphere,
forest cover has actually increased
by nearly 250,000 square kilometers.
That’s about the size of the UK.
And at the same time, we also know
that mass timber construction,
specifically in Europe,
has expanded rapidly.
And then outside of these areas,
especially in the regions
where deforestation is rampant,
we need to proceed much more carefully,
and we need to assess the safeguards
that will ensure that an increased
demand for wood in buildings
does not result in forest loss
but, on the other hand, drives more
sustainable forest management.
Because one thing is very clear:
wooden buildings will only
be a sustainable climate-smart solution
if forests are sustainably managed.
Otherwise, it will only be greenwashing.
So we also need to ensure
that an increased demand for wood
does not harm local communities.
It is really important
that countries assess
the total area that they can devote
to sustainable forest management
and ensure that that does not impinge
on local communities’ activities,
such as agriculture.
We know there are limits to the number
of wooden buildings that can be built,
but clearly we are far
from hitting those limits today.
So I do have a vision,
a vision that within this next decade,
we can create a “climate smart
forest economy” where forests,
forest products, forest peoples,
homes, and buildings
can avert a full-scale climate emergency.
This will not be easy,
nor will it be straightforward.
We will need more research, and we will
need all stakeholders to work together,
but clearly, thinking of wooden buildings
as a planetary carbon
sequestration strategy
is an idea worth exploring,
both for its necessity
and also for its boldness.
So what are the climate benefits
of building with wood?
Well, we know that roughly on average,
a wooden building has a climate footprint
which is about 50% lower than any building
built with cement and steel.
In addition, there’s carbon savings
because the wood used in the building
is storing carbon from the trees,
and it remains for the lifespan
of the building.
The building can also be designed
to be deconstructed,
and where they are deconstructed,
they can be used for something else
or they can be recycled.
In short, we can transition from buildings
being a carbon source
to being a carbon sink.
Isn’t that a vision worth chasing?
And there are so many other advantages
of building with wood,
using mass timber technology:
The construction
basically gets 30% faster.
It uses 50% less crew.
Usually, you have 60% less truck traffic.
The construction sites are much quieter,
and there’s less disruption.
And mass timber hospitals
were actually built
during the COVID 19 pandemic
in Wuhan, China in less than two weeks.
So have we started making wooden
buildings yet? Well, we have.
And in fact, in Norway,
that’s the tallest timber tower,
and the house in the Netherlands
is the tallest residential building.
And here in Geneva, I’m standing
in front of two wooden buildings
that house migrants from Afghanistan,
from Eritrea, and from Iraq.
Wood was chosen because of the possibility
to have modular constructions,
and these modular constructions respond
to different migration patterns
and migration flows,
in addition to which wood was chosen
because the buildings can be deconstructed
and may be used for something else.
The wood was actually sourced
from local forests
in the mountain range
just behind Geneva, in the Jura.
And then finally, wood was chosen
for its biophilic properties,
such as stress reduction,
and that’s important
for migrant populations
that arrive in Geneva,
often with a lot of troubles and scars.
So how can we scale this movement?
Well, governments can help
by stimulating demand.
And for example, in Japan, as of 2010,
there is a law that mandates
that all buildings that are up
to three stories high be made of wood.
And in France, as of 2022,
the government has required
all public buildings be made 50% of wood
and 50% of renewable materials.
Governments need also
to put in place the right policies,
including for sustainable sourcing
of timber and timber products,
inciting incentivizing restoration
where it makes place,
and also to facilitate
the flow of financing,
such as through tax credits or subsidies.
Governments and industry can work together
to spur innovation by investing
in research and professional education.
So there is a future
in which cities can support forests,
and forests can support cities,
and where one of the most
cost-effective ways
to reduce greenhouse gas emissions
is buildings made out of trees.
I believe that it will take
all of us to chart this future,
and we all have our role to play.
We can, for example, decide to buy
only sustainable forest products
when we buy furniture,
and we can also decide
that our next home or office building
can be made out of trees.
Thank you.