NEWS
will warm or cool the planet. Overall,
tree canopies are darker than grassy
vegetation, and thus absorb more
sunlight and heat – this could lead to
warming.
Advocates of trees-for-carbon projects
have not taken this into account.
“What concerns us is that the trees-
for-carbon projects distract us from
the real issue: the urgent and immedi-
ate need to reduce carbon emissions,
especially by reducing fossil fuel use,”
adds Bond.
Figure 2: The researchers found that
the benefits of afforestation for reduc-
ing atmospheric carbon are paltry,
while the costs to Africa in lost land for
agriculture, livestock, conservation, and
in managing vast plantations will have
to be borne for the foreseeable future
quester a tonne of carbon – a “very
conservative” rate according to Bond
– the total amount required to bal-
ance out this yearly increase would be
USD47 billion.
“The World Bank’s contribution of a
billion dollars [to the Bonn Challenge]
is less than 0.5% of what would be
needed over the next 10 years,” ex-
plains Bond. “And that billion dollars,
spread over 100 million hectares of Af-
rica, works out at USD10 per hectare –
a bargain for the industrial countries of
the world.”
The researchers’ calculations show that
should Africa reach its target of forest-
ing 100 million hectares, only 2.7% less
carbon dioxide would enter the atmos-
phere each year.
“If that seems small, consider that the
coal used in the industrial revolution
took 400 million years to accumulate,”
Figure 3: Emeritus Professor William
Bond, former Chief Scientist of SAEON
and lead author of the new research
adds Stevens, a co-author on the study.
“Can you really expect to stuff it all
back again in the next few decades?”
The team concludes that converting
Africa’s grassy landscapes to tree plan-
tations will not only do little to reduce
greenhouse gases, but that the fund-
ing for the programme is a small frac-
tion of what is needed. African coun-
tries could also be locking themselves
into plantation forestry for decades at
the expense of other industries, such
as food crops, livestock farming and
conservation.
Furthermore, the amount of carbon
that tree plantations store depends on
intensive management: suppressing
fires, felling trees and then storing the
carbon, and replanting every decade
or two for the foreseeable future. This
is something African countries would
need to deliver on.
Exporting emission problems
The researchers also raise the point
that there isn’t even scientific agree-
ment on whether such tree plantations
Indeed, trees-for-carbon projects can
be seen as a way for industrialised
countries – the major sources of green-
house gases – to export fossil-fuel
emission problems to Africa.
The researchers highlight that they
strongly endorse planting trees to re-
store destroyed forests and in urban
areas for shade and enjoyment. They
also support retaining the intact forests
that remain. But that trees-for-carbon
projects are based on wrong assump-
tions. “For tree planting to be positive,
it needs to be the right trees in the
right places,” says Lehmann.
A better way of supporting Africa’s
transition to a warmer future might
be to promote energy-efficient cities
in this rapidly urbanising continent so
that Africa follows a less carbon-inten-
sive trajectory without destroying its
grassy landscapes.
* Bond WJ et al. (2019) The Trouble with
Trees: Afforestation Plans for Africa,
Trends in Ecology and Evolution. htt-
ps://doi.org/10.1016/j.tree.2019.08.003
LISTEN to Professor Bond being in-
terviewed on the Afternoon Drive
with John Maytham here: http://bit.
ly/2QpTiVK
Figure 4: The researchers support retaining the intact
forests that remain and strongly endorse planting trees to
restore destroyed forests (Photo: Shutterstock)
Grassroots
Vol 19
No 4
November 2019
36