14 September 2019 | New Scientist | 41solutions, with solar photovoltaics, wind
power and electric mobility all much more
economically competitive. And there is
cultural buy-in. Harley-Davidson just
announced it is going electric. For me,
that is hugely symbolic.So could we be at a positive tipping point in
humanity’s response to these threats?
I very much hope so. Change is happening.
We may be entering a new era, a renaissance
in which sustainability is essential to the
success of businesses.
The question now is whether the change
is happening fast enough to keep us within
the safe operating space. And we don’t know
the answer to that yet. ❚Fred Pearce is a New Scientist consultant and the
author of When the Rivers Run Dry: The global
water crisis and how to solve itIn the past 10 years, have you become more or
less optimistic?
Well, the trend lines on the state of the planet
make me more pessimistic. We are running out
of time. We need to bend the curves within the
next few years. For climate, we have to cut
emissions by half over the next 10 years,
or we will be well into the high-risk zone.
Still, there are some reasons for optimism.
Over the past 10 years, we have seen an
exponential rise in sustainable energy“ All of these
effects may
foreshadow the
breakdown of
other systems”
the Amazon and we know rainfall declines
thousands of kilometres away.
Science is still struggling to assess how
much we can disrupt the hydrological cycle
without crossing dangerous thresholds. So,
for now, we have set a boundary where humans
remove no more than a tenth of the natural
run-off. It is a proxy for disruption of the
hydrological system as a whole.
What about biodiversity? Does the number
of species on the planet actually matter?
Biodiversity is essential. A living biosphere
regulates the water cycle and climate, cleans
the air and much more. A dead planet wouldn’t
be habitable. So somewhere there must be a
boundary. Our interest isn’t in the number of
species itself, but in functional biodiversity:
what is needed to maintain Earth’s life-support
systems. Scholars are developing a biosphere
integrity index to try to measure this. For
now, we rely on the more established data
on species extinctions.
So how is our planet doing on this measure?
The natural background extinction rate is
up to 10 species per year, but the rate today is
more than 1000 a year. We set the boundary
at 10 times the background rate. I admit it is
rudimentary, but I do believe a globally agreed
scientific target for cutting extinctions would
help policy-makers – like the “below 2 degrees”
temperature target on climate change.
Might there be other boundaries out there?
I don’t think so. Nobody has made a convincing
argument for a tenth boundary, or that we
should take away any of the nine. But in our
review next year, we are likely to add plastics
to the novel entities category, and will improve
some other boundaries, such as biodiversity
and freshwater.
What about a people boundary? Human
population, say? After all, it is the pressure
of people that is causing the problems.
Yes, but the boundaries describe Earth’s life-
support systems that keep us in the Holocene.
The systems themselves aren’t defined by
human activity. But of course, within that,
our interest as humans is in how we should
use the safe operating space that we identify:
how to stay within it and share it fairly.
The international community has
made some progress on this. There is the Paris
climate agreement. And the UN’s Sustainable
Development Goals explicitly recognise four
boundaries within which we have to reach
goals: water, biodiversity, oceans and climate.
Straining the
limits: Arctic sea
ice is melting at
an unprecedented
rate (left), and
plastic pollution
is piling up (below)GUY MOBERLY/ALAMYK ADIR VAN LOHUIZEN/NOOR FOR CARMIGNAC FONDATIONScience to save the world
Tech solutions to our planetary problems
will be a big part of our live show this year
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