26 | New Scientist | 1 February 2020
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Editor’s pick
We need a unit of personal
environmental impact
Leader, 18 January
From Alain Williams,
Watford, Hertfordshire, UK
You call for clear-headed
assessment of schemes to reduce
our impact on the natural world.
We also need a new unit for a new
measure of the environmental cost
to the planet of a person in a year.
The point would be to allow us to
compare individuals: people who
have acted to reduce their footprint,
people with different lifestyles –
jet-setters, vegans, commuters –
and people in different countries.
This measure should account
for use of energy, water, plastics,
metals and so on. While the formula
to calculate it might be subject to
disagreement, at the moment we
have many types of measure of
impact, which confuses many and
makes it hard to compare people.
The name of the unit? I propose
a Thunberg. We could say that the
average European is 14 Thunbergs,
the average African 3, and so on.The benefits of cooking
lessons and rough grazing
4 January, p 32
From Christine Granville-Edge,
Flaxby, North Yorkshire, UK
Thank you for reporting your
experiment with going vegan.
I suspect one of the main issues
that puts people off trying this is
that basic nutrition and cooking
skills are no longer taught a lot
in UK schools. This is a reason,
alongside time limitations, for
people falling back onto ready
meals and processed food.
The ability to think sideways
about how to achieve flavour,
visual appeal and a balanced meal
comes easier to those with varied
cooking skills. Working in a health
food shop, I am continually
surprised, and often appalled,
by people asking how to cook
vegetables, or to get their children
to eat them in the first place.
People who haven’t grown upwith one or both parents cooking
from scratch will find creating
vegan food much harder than
those who have had to cater for
themselves, in spite of the best
efforts of popular television cooks.
That said, it is getting easier to
create tasty, nutritious vegan food
from produce available in major
supermarkets and independent
health food shops.From Sandy Henderson,
Dunblane, Stirling, UK
You might think that as a livestock
farmer I would resent vegans
claiming that my way of life is
unethical, and you would be right.
You quote Michael Clark saying
that eating animals fed on plants
must be less efficient than people
eating plants. This ignores the fact
that many herbivores can, and do,
get much more feed value out of
plants than people. What’s more,
much of the north and west of the
UK and Ireland can only be farmed
practically using grazing animals.The editor writes:
Much of the world’s beef is now
produced in intensive feedlots –
pens without pasture. This may
have a lower carbon footprint thanpasture-fed beef. We suspect that
most of that is done on fertile land,
not rough grazing. It is even harder
to find figures for other meats. We
note that in the UK, upland sheep
production is only marginally
viable even with EU subsidies.You will always get
less than you ask for
Letters, 2 November 2019
From Klára Ertl,
Amsterdam, the Netherlands
Extinction Rebellion’s demands
are unrealistic, says Mike Clarke.
I think they are deliberately so.
In persuasion psychology there
are two common techniques
called the “foot-in-the-door”
and the “door-in-the-face”. The
first of these involves asking for a
small favour to later ask a larger
one, referring to earlier deeds or
promises. This is very common
when asking for donations:
“You are such a generous person,
having bought many of our gifts
in the past to support children in
need. Would you now consider a
monthly donation?”
The second involves asking for
something large, knowing that it
won’t be granted, and then askingfor something small, trusting that
you will get a concession in return:
“Mum, I want a horse.” “No way.”
“Can I just have a hamster, then?”
Extinction Rebellion uses both
strategies. When governments
declare a climate emergency,
activists use this to demand action
consistent with that declaration.
They will insist on carbon
neutrality by 2025 in order to have
more chance of it by, say, 2050.The world dodged a bullet
with the Montreal protocol
30 November 2019, p 7
From Birger Johansson,
Umeå, Sweden
The UN Environment Programme
has defined the huge scale of the
task of limiting temperature rise
to 1.5°C, reports Adam Vaughan.
But things could be worse.
In recent research, Rishav Goyal
and his colleagues showed that the
world dodged a bullet when the
1987 Montreal protocol to protect
the ozone layer was agreed,
phasing out chlorofluorocarbons
(CFCs) (Environmental Research
Letters, doi.org/djjd). CFCs are
very potent greenhouse gases, as
well as ozone destroyers. Their