The Economist UK - 28.03.2020

The EconomistMarch 28th 2020 Science & technology 77

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Glen Peters of Norway’s Centre for Interna-

tional Climate Research published esti-

mates suggesting that if, as forecast by the

Organisation for Economic Co-operation

and Development (oecd) at the beginning

of the month, the world’s gdpwere to grow

by 1.5% this year (a halving of its pre-pan-

demic estimate), this would lead to a 1.2%

decline in carbon-dioxide emissions. This

decline, even though the economy would

still be growing, would be because of the

increasing carbon-efficiency of economic

activity. Since then, the prospects for the

global economy have worsened considera-

bly. Most forecasters now expect world gdp

to shrink this year, and some predict a con-

traction of fully 4%—twice the decline

seen after the global financial crisis of

2007-09. That will make the fall in emis-

sions even bigger.

But not, perhaps, for long. In 2009,

worldwide CO 2 emissions from fossil fuels

and cement production dropped by 1.4%. A

year later, however, they were growing

again by 5.8-5.9%—faster than they had

done since 2003. By the end of 2010, annual

emissions were greater than they had ever

been (see chart). Overall, therefore, the fi-

nancial crisis made little difference to the

quantity of CO 2 in the atmosphere.

Subsequent analysis has shown that the

rise of emissions after the crisis of 2008

was caused especially by rapid growth in

certain large emerging economies, notably

those of China and India. Low fossil-fuel

prices were part of the cause. But there

were also stimulus packages deliberately

intended to promote carbon-intensive ar-

eas of business, such as construction.

Sadly, there are signs of a similar pat-

tern of environmentally inappropriate

stimuli happening now. Canada, for in-

stance, is preparing a multibillion-dollar

bail-out for its oil and gas industry. Airlines

are clamouring for help, too. Several Chi-

nese provinces have announced plans to go

on a 25trn yuan ($3.5trn) construction-

spending spree. And other ideas that have

been floated in China include vouchers to

encourage people to buy cars.

Meanwhile, an analysis by Bloomberg-

nef, a clean-energy-research firm, finds

that solar power may take a hit, as govern-

ments preoccupied with fighting the virus

postpone decisions to commission new

plants and to agree on targets for the

growth of renewable energy. China, in-

deed, has already deferred an auction for

the right to build several huge solar farms.

As a result, Bloombergnefsuggests, for the

first time in decades the amount of solar-

energy capacity installed this year could be

lower than that in the previous one.

There is also the question of what hap-

pens to cop26, the 2020 United Nations

Climate Change Conference which is sup-

posed to be held in Glasgow, in November.

This was meant to be a moment for the

world’s governments to come forward with

their most ambitious plans yet to address

the problem of rising greenhouse-gas

emissions—the first summit of such mo-

ment since the one held in Paris in 2015,

which agreed to limit global warming to

1.5-2°C above pre-industrial levels. British

ministers and unofficials are now discuss-

ing whether to shift the meeting into the

early months of 2021.

In the shorter term, the focus is on what

will happen to an important preparatory

meeting scheduled to take place in Bonn,

in June. To get agreement at cop26was al-

ready going to be challenging, even with-

out a global pandemic to detract political

minds and resolve. Delaying the meeting

in Bonn will make things worse.

A window of opportunity?

There are a few accidental consequences of

the epidemic, though, that may have long-

term effects which greens would see as

positive. One concerns everybody’s favour-

ite environmental whipping boy, the air-

line industry. Before the crisis, this indus-

try agreed to the launch next year of a

scheme called corsia, which has the goal

of maintaining net global emissions from

aeroplanes at the annualised average of the

two years 2019 and 2020. Emissions be-

yond this average would have to be offset

by such things as tree-planting projects

and schemes to capture methane from

landfill sites. Clearly, emissions by airlines

in 2020 are going to be abnormally low,

which will, if the rules are followed, lower

the threshold above which these offsets

would be invoked. Whether that happens

in practice will depend, though, on wheth-

Crash and recovery

Global annual industrial CO2 emissions, gigatonnes

Source: Global

Carbon Project

*Based on trend in five

years prior to event

1020009080701960 18

0

10

20

30

Emissions^40

Extrapolated

trend in emissions*

First oil

crisis Second

oil crisis

Fall of the USSR

Asian financial

crisis

Global

financial

crisis

P

ollution anddisease have long been

associated in people’s minds. The very

word “malaria”, for example, means “bad

air” in Italian. But the germ theory of

infection, developed in the 19th century,

knocked on the head the idea that it is the

air itself which causes illness. Rather,

bad smells indicate sources of patho-

gens, such as sewage, which are best

avoided. A paper just published by a

group of Italian researchers does, how-

ever, posit the idea that sars-cov- 2 , the

virus behind the covid-19 pandemic,

might be getting a helping hand from

atmospheric pollution.

The paper in question, by Leonardo

Setti of the University of Bologna and his

colleagues, has not yet been through any

process of peer review. Such early re-

leases are, though, becoming common-

place for covid-19-related work, on the

assumption that holding ideas back for

bureaucratic approval might cost lives.

Dr Setti and his associates found them-

selves wondering why (even allowing for

time lags caused by its arrival in different

places on different dates) sars-cov- 2

seemed to spread much faster in Italy’s

north—specifically in the wide plain that

forms the valley of the Po—than in other

parts of the country.

Their hypothesis is that the catalyst

was pollution—specifically, small air-

borne particles that might carry the virus

on their surfaces. These are usually far

more abundant in the Po valley than

elsewhere. In the paper, the researchers

cite previous work from other places

which suggests that influenza viruses,

respiratory syncytial viruses and measles

viruses can all spread by hitching lifts on

such particles. And they make a good

case that, allowing for a 14-day delay

caused by sars-cov- 2 ’s incubation per-

iod, the daily rates of new infections in

the Po valley correlate closely with the

level of particulate pollution.

An alternative explanation for this

correlation might be that, rather than

carrying the virus themselves, airborne

particles increase susceptibility to in-

fection in those who encounter the

pathogen by some other means. Either

way, though, a reduction in airborne-

particle levels may be a second way,

independent of reduced human contact,

that lockdowns will help stop the virus

spreading around.

Heat and dust

Covid-19 and pollution

Airborne particles may assist the virus’s spread