42 | New Scientist | 27 February 2021In 2016, Priscilla Chan took to the stage at a
meeting in San Francisco and announced that
her foundation would work to ensure that an
entire generation of people would never get
seriously ill. “We’ll be investing in basic science
research with the goal of curing disease,” she
said. To that end, Chan and her husband,
Facebook CEO Mark Zuckerberg, put $3 billion
into research aimed at preventing, managing
or curing all diseases by the end of the
21st century. Tha isn’t merely curing breast
cancer or Alzheimer’s or diabetes or strokes,
but curing all disease. Oh, and increasing
global life expectancy to 100.
Even by Silicon Valley standards, it is an
ambitious goal. Even if Chan and Zuckerberg
end up investing their entire fortune, currently
around $60 billion, it would be a drop in theAT
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/PANOS^ PICTURESCure all
disease
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carbon-capture plant
in Hinwil, Switzerlandrequire gigantic and unprecedented
growth. Other carbon-capture start-ups
require similar expansion before we get to
a capacity where it will make a global
difference. So we will invest in this sector,
let’s say $100 billion or so, but save most
of our money for the organic approach.A trillion trees?
The method can be summarised in three
words: grow more trees. Trees draw down CO 2
and lock it up, at least for the lifetime of the
tree. If you plant enough of them, you could
suck out a lot of the CO 2 in the atmosphere.
The problem is that we would need to do this
on a gigantic scale, which brings multiple
problems. Perhaps the biggest hurdle is the
question of where they will all go. A team at
ETH Zurich in Switzerland used data on forest
cover from Google Earth and a machine-
learning algorithm to predict which new areas
could support forests. There is enough land,
it seems, for 900 million hectares of forest,
an area about the size of the US.
Let’s say we paid to plant around 500 billion
new trees. According to the ETH Zurich
analysis, once the trees are mature, that
number might draw down and store
205 gigatonnes of CO 2. Given that each part per
million (ppm) of CO 2 is equal to 2.13 gigatonnes,that would bring the ppm down to about
320, its level in the mid-1960s. Currently,
we are at around 416 ppm.
This seems to be the best way to buy us some
time at least. Of course, there are lots of details
to work out. Simon Lewis at the University
of Leeds, UK, who studies the interactions
between forests and climate change, thinks
the 205 gigatonnes is an overestimate. It is also
fair to say that there are many demands on
“spare” land, not least agriculture, housing and
recreation. But there does seem to be a lot of
currently wasted land that we could redevelop
in a massive tree-planting scheme. Allowing
land to regenerate on its own can also be
hugely effective, as can forestry management
incentives aimed at locking away more carbon.
This epic afforestation is going to be
expensive at roughly $400 billion per year, yet
it would surely be a sound investment. A 2018
report from the Intergovernmental Panel on
Climate Change found that keeping us below
1.5°C of warming above pre-industrial levels
would cost about $2.5 trillion per year until
2050 in investment in the energy sector,
and $775 billion per year on measures to
reduce energy demand. The financial cost
of global warming above 1.5°C is so diabolical
that the economic benefits of staying below
this threshold are four or five times the size
of the investment.CL
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