New Scientist - USA (2020-07-04)

4 July 2020 | New Scientist | 39

process. To achieve net zero, we need to
have bigger carbon sinks. That’s because
most activities that emit CO2 can be cut
down to zero, but not all. Agriculture or
aviation can’t be, for example, at least not
with foreseeable technologies. We need to
be able to offset those emissions by actively
removing CO2 from the atmosphere, creating
anthropogenic carbon sinks that go beyond
the natural carbon sinks that already exist.
The simplest way to create a carbon sink
is by planting trees. The trees store carbon
in their branches and roots, and with time,
the soil carbon also builds up. We need to
increase the forest cover enough that we
build up that carbon biomass, and this
offsets the emissions we cannot bring
down to absolute zero.

You previously instigated an annual effort to
keep track of global emissions. To what extent
can we trust emissions data from governments?
Governments’ reports to the United
Nations are also scrutinised, checked by
independent experts and validated by a team
of experts at the UN Framework Convention
on Climate Change, the UN wing that deals
with international climate actions. The issue

is that, for the moment, only a subset

of countries does this. Under the Paris

Agreement, all countries will need to report,

but it will take some time to scale up.

Isn’t it critical that we have some independent

measure of carbon emissions to track countries’

progress under the Paris climate deal and hold

them to account?

Absolutely. We now have satellite data,

which measures vertical columns of CO2

in the atmosphere above a given location.

But we have to be realistic about what these

observations will be able to do. I think, at

least in the next 10 years, the best case would

be to raise questions about the accuracy of

emissions reports.

One of the big messages that the public picked

out of the UN climate science panel’s special

report in 2018 was that there are “12 years

to save the world”, to ensure global warming

doesn’t exceed the target limit of 1.5°C. How

helpful was that?

I didn’t find it super helpful. What are you

going to do in 10 years’ time? You’re just

going to hope people will have forgotten

you’ve ever said that. I understand that it gave

a sense of urgency that wasn’t there before,

but it’s not 12 years anymore. I’m going to

work on climate change all my life. If we miss

the 1.5°C target, then I will fight for 1.6°C or

1.8°C, and if we miss the 2°C target, I will fight

for 2.4°C. So for me, the fight is permanent.

The lower the level we’re fighting for, the

better it is. There are some degrees of

warming I don’t even want to think about.

You said at a talk two years ago that before

you die, you think you will live in a world where

people no longer eat animals and can breathe

clean air in the middle of cities. Do you still think

that’s the case?

The state of the science is clear. We have the

Paris Agreement. We’ve had all the youth

coming up and saying “we want a better

world”. We’re not over the big polluting

phase, but we’ve progressed in our thinking

enormously. There is no real obstacle other

than within ourselves.  ❚

Adam Vaughan is chief reporter at

New Scientist

During lockdown,

cyclists flocked to

The Mall in London,

which is usually

choked with traffic