The Economist - USA (2020-03-28)

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The EconomistMarch 28th 2020 Science & technology 69

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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
GlobalannualindustrialCO2emissions,gigatonnes

Source:Global
CarbonProject

*Basedontrendinfive
yearspriortoevent

1020009080701960 18

0

10

20

30

Emissions^40
Extrapolated
trendinemissions*

First oil
crisis Second
oil crisis

Fall of the USSR

Asian financial
crisis

Global
financial
crisis

P


ollution anddiseasehavelongbeen
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

formsthevalleyofthePo—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
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