New Scientist - USA (2020-07-04)

38 | New Scientist | 4 July 2020

Electric bikes are increasingly affordable,

which opens the possibility of cycling from

suburbs in a way that didn’t exist before.

What about flying?

Aviation has always been very problematic

for climate change. There’s no credible way to

have net-zero emissions by 2050 and aviation

as it was before covid-19, and the industry

didn’t engage at the right level on cutting

emissions. Before this crisis, the push was for

bigger airports and so on. Now, with covid-19,

the number of flights has been cut by 75 to 80

per cent. It is going to be years before they can

even think about going back to the passenger

levels they had just a few months ago.

So now we have the opportunity to ask:

what is an appropriate number of flights? We

could have some leverage, too. The aviation

sector has had exonerations for taxes that

were completely unjustified. They haven’t

had the net-zero target, which is also

unjustified. So I think these are the two

levers governments can use when awarding

recovery packages to aviation companies.

What should governments be doing to take

advantage of the opportunities at the moment

to rethink economies and societies?

Government investments post-coronavirus

should focus on those actions that both

support workers and enable the structural

changes needed to deliver net-zero

emissions, so we are more resilient in the

future. In terms of investments, these

should include support for the full

electrification of transport, massive

renovations of buildings and tree-planting

and restoration of natural habitats. Actions

that lock us into fossil fuels, such as building

roads, should clearly be avoided.

In the UK, how big is the gap between the

government’s legislation targeting net-zero

emissions by 2050 and the policies required

to get us there?

The UK has been very successful in the

power sector, moving out of coal in particular

by taxing it and providing subsidies to

renewables. But the UK has been behind on

strategies and implementation to move

forward on buildings, transport and

agriculture. The government has recently

published a road transport decarbonisation

strategy, which had some really good points

in it. So there are things in the making, but

we are not there at the moment. When you

look at what the UK has delivered, it’s not

been enough.

What policies must the UK implement to stand

a chance of hitting net zero by 2050?

Two-thirds of UK emissions are due to

transport, buildings (mainly heating) and

industry. Government departments should

have ambitious implementation strategies

in each of these sectors. One thing that has

worked well in the UK is the clear signal the

government has provided to move away from

coal power generation and to phase out

petrol and diesel cars from, currently, 2035

and gas boilers in new homes from 2025.

These announcements need to be

accompanied by a clear trajectory, with

support to develop skills and supply chains,

ensure performance and compliance and an

appropriate carbon price on the use of fossil

fuels. The UK also urgently needs to grow and

manage its woodland so biomass can play

its important role, and to develop carbon

capture and storage, which will be a key asset

in the transition to a zero-carbon economy.

You are an expert on the global carbon cycle.

How has our understanding of where our CO₂

emissions end up improved over the years?

We have two sources of emissions – fossil

fuels and land use change – and three places

where those emissions end up – the carbon

sinks of the atmosphere, land and ocean. If

we had perfect knowledge and perfect data,

then the five terms would add up to exactly

zero every year – and, of course, they don’t.

We call this mismatch the carbon budget

imbalance: it’s really like a quantitative

measure of the things we don’t know. The

cutting-edge research is to find out what is

behind that.

Any working hypotheses?

It’s likely to come from either the ocean sink

or the land sink or both, rather than the

emissions, because the structure of this

imbalance hasn’t changed in 60 years and

the emissions have quadrupled. If it came

from some uncertainty in the emissions,

then it would have been a lot smaller at the

beginning of the time series and bigger now,

and it’s not. A possible explanation is that

most models don’t have nitrogen limitation,

where lack of nitrogen impairs plant growth

and therefore how much CO2 they absorb.

Overall, what is happening to our natural

carbon sinks?

The weakening of the Amazon rainforest as a

sink is really, really scary. We need the carbon

sinks to become stronger to help us in the

management of this decarbonisation

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“ There is no way

to have net-zero

emissions and

aviation as it was

before covid-19”