Right, here's the challenge.
How do we build and heat our homes
without over-heating the planet?
Net zero. Net zero. Net zero. Net zero.
So net zero is the plan, but how are we
actually going to get there?
Because our buildings are responsible for
28% of total CO2 emissions.
And when you add in emissions from building
those buildings, that number goes up to 39%.
So how on earth are we getting to net zero?
Luckily, scientists and experts have been
working for years on this. I've been speaking
with some of them and going through
the advice and evidence of many more.
And one thing is definitely clear.
We're going to have to do something about
our buildings.
Especially how we heat them.
Heat is around half of the energy that's used
around the world, half. And the emissions
from heating are about a third overall.
Gas is by far the biggest way that we produce heat,
not just in the UK but around the world.
In the UK we are a particularly gassy country.
About 84, 85% of homes are
connected to the gas grid.
There are about 23 million homes with gas boilers.
And while gas is slightly cleaner than burning oil
or burning coal, it's still a fossil fuel.
So it's all got to go.
Right. So, swap out 23 million boilers?
It's a little bit of a logistical challenge there.
But more importantly,
what are we going to replace these with?
There is an idea that you could just convert
the existing gas grid to run on hydrogen.
That would be piped into people's homes and then
burnt in boilers, much the same way it is now.
But burning hydrogen for heat looks like
an extremely expensive and inefficient option.
Right. What else could we do then?
It looks like heat pumps will be the cheapest
long-term option for most people.
So a heat pump, as the name suggests,
it pumps heat from the air, the ground,
or even rivers and the sea into your home.
A gas boiler might be 80 or 85% efficient,
but a heat pump will give you about
three and a half units of energy for
every unit of energy you put into it.
So that's 350% efficiency.
They're just so much more efficient than
a boiler will ever be.
Sounds a bit like a no-brainer,
but there's still a few hurdles to overcome
because heat pumps are still pretty expensive
and putting them in can be a complex operation,
maybe requiring new radiators and insulation.
It shouldn't be a personal responsibility.
There should be help for people to do this.
So it's the role of government
to make this really easy for people.
You should be able to phone up an advice line
and be offered grant funding or offered a free
or low-cost loan and be able to do this
at no upfront cost and no upfront hassle to yourself.
The reality is that anything like that seems
pretty far away.
And in 2019, the UK's Climate Change Committee
said that over ten years after
the Climate Change Act was passed,
there is still no serious plan for
decarbonising UK heating systems.
So yeah, still some huge challenges to overcome.
for these to be a viable option in our homes.
And of course that's just one aspect of
making our buildings net zero friendly.
There's still things to think about,
like electricity and insulation,
but this is all just about our buildings as they are.
What about building. Constructing our homes.
Because at the same time, the global population
is still rising. And that means the need for
new housing, and the materials to build it with,
is going to rise too.
Specifically, concrete.
Concrete is the most widely used material
on the planet after water.
In three years China
consumed more cement,
the glue that holds
concrete together,
than the US used in the
entire 20th century.
And if cement production
were a country,
it would be the
third largest
emitter in the world.
And that's a lot to do
with the production of
clinker, the key part of cement,
because turning the raw materials,
mainly limestone and clay, into calcium oxide
produces a lot of CO2, just part of the process.
And producing concrete also uses
a huge amount of water.
In 2050, an estimated 75% of this water will likely
be taken from regions that won't have enough
to satisfy human needs.
So how do we reduce its environmental impacts?
Everyone might think that the best way to do it
will be using less concrete, but that will
also bring quite a lot of social inequalities
because we need infrastructure for living.
So other options include recycling concrete
and waste CO2, reducing the amount of clinker
or swapping it for other materials.
And there's even self-healing concrete
with an enzyme in it that
responds automatically to cracks.
In 2021, cement makers around the world
did pledge
to cut emissions by up to 25% by 2030
to reach net zero by 2050.
So that's some ambition being shown.
But we have to interrogate this a little bit further
because that plan relies on carbon capture.
And there's two things with that.
Firstly, it could make concrete
much more expensive.
Who's paying for that? And number two.
We still need to answer the questions of
what are we going to do with that CO2
once it's under storage?
So in order for the industry to transition
to low carbon, it's not just technology that we need.
There are many things that could be done just now,
but we don't have the right policy or
the right standards that enable us
to actually adopt it rapidly into practice.
Concrete is a material that we take for granted.
We think, Oh, it's not sophisticated,
it is not beautiful, so it might not be interesting.
But when we think about
the vast amount of concrete
that we actually use in our society,
we need all hands on deck to try to make
this material more sustainable, more efficient,
so we can continue using it
for the many years to come
to resolve our infrastructure needs.
Okay, we've only just scratched the surface
of these two huge topics, but when it comes
to net zero, there's a lot of chat about
things we need to cut in our lives,
but there's a lot of positives too,
especially when it comes to our buildings.
So a dream outcome for me in 2050 is that
we're all living in houses that are warmer,
quieter, cosier and cheaper to run.
And we've met our climate change targets.
That would just be fantastic.