OVERPOPULATION FEATUREcologist Emma Olliff doesn’t want her
own children. Not biological ones at least.
She made the decision quite young, she
says, but she only fully consolidated the
reasons why in her early 20s.
“I did a marine biology degree, and
then a biological diversity masters,” she
says. “And so was made very aware of human
impacts on the environment, and how more of us
is only going to make it worse.”
She isn’t alone. The idea of reducing the number
of children you choose to have – or even going
child-free – for environmental reasons has had
a surge of interest in the past few years, with a
particular focus on the climate impact of adding
another person into the world. Some also say they
are concerned about bringing children into a world
with such an uncertain ecological future.
But not everyone is convinced about the merits
of focusing on population as a solution to the
world’s environmental woes. Some people point
to the dark history of enforced population control
by political leaders or movements.
All this feeds into a
debate on how much
emphasis should be put
on reducing the number
of people on the planet
to tackle climate change.IN THE CROWD
Olliff is a board member
for Population Matters,
a UK cha rity t hat
campaigns for people
to have smaller families
as a way to increase
sustainability. And there
a re some inf luent ial
environmentalists
a mong t he cha rity’s
patrons, including Sir
David Attenborough, Ja ne Goodall a nd Ch ris
Packham, which gives weight to the argument.
Indeed, few people would dispute that there is
some physical limit to how many people can live
on Earth sustainably in the long time. There are
currently 7.7 billion people on Earth, and this could
rise to 9.7 billion by 2050 and 10.8 billion by 2100,
according to UN projections. But the actual increase
will depend hugely on what happens with policies,
healthcare and culture over the next decades.
So how many people is too many? Trying to answer
that is tricky. Even defining the term ‘overpopulation’
is hard. “Ask eight different people [and] you get
eight different answers about what overpopulation
means,” says Raywat Deonandan, associate professor
in global health at the University of Ottawa, andE
“THE PICTURE IS MUCH
MORE COMPLICATED THAN
‘FEWER PEOPLE MEANS
LOWER EMISSIONS’”
an expert in epidemiology. Deonandan himself
retreats to the standard demographer definition of
overpopulation: the point at which a population
exceeds the land and ability to sustain it. But this
opens up the question of what ‘sustain’ actually
means. “Traditionally ‘sustain’ just meant ‘keep
you alive’,” says Deonandan. “It’s not really what
we mean any more.”
In climate terms, sustainability translates into the
need to maintain a relatively stable climate, which
a report from the International Panel on Climate
Change (IPCC) last year showed means lowering
emissions enough to keep global temperature rise
to no more than 1.5°C.
Most of the carbon budget for this has already
been used up, explains Kimberly Nicholas,
associate professor in sustainability science from
Lund University in Sweden. “So if we’re going
to avoid da ngerous climate cha nge, which
I really hope that we do, we have to radically
and rapidly reduce emissions that we have today.
That’s flying and driving and burning fossil fuels
and raising livestock.”PLANET OF TWO HALVES
The IPCC recognises
population as one factor in
greenhouse gas emissions.
Its projections show that,
if all else is equal, lower
populations in the future will
support lower emissions, and
the most sustainable future
scenario has a population
lower than today’s.
But the picture is much
more complicated t ha n
‘fewer people means lower
emissions’ for one very clear
reason: inequality.
The average greenhouse
gas emissions emitted per
person vary hugely from country to country. They
sit at around 20 tonnes of CO 2 equivalent per year
for each person living in the US, for example, but
around two tonnes per year for Indian citizens. In
the UK, they average seven tonnes per year. And
this isn’t even accounting for the many products
made in Indian factories that are consumed in the
UK and the US.
This means that where babies are born tends to
influence their total climate impact significantly,
with people born in high-consumption, rich countries
far more likely to lead high-emitting lifestyles.
Another way of looking at emissions inequality
comes down to wealth. An Indian businessman flying
often by private jet will have far higher greenhouse
GETTY IMAGES gas emissions than other Indians on average; 2