后备箱Fighting Fire with Fire

2021年1月21日发(作者：结合水)





African savannah wildfire





















(Credit: World Agroforesrtry Center)





In
African
savannahs,
or
grasslands,
wildfires
can
either
be destructive or beneficial. It all depends on when those fires
occur.
Scientists
at
the
World
Agroforestry
Center
have
developed
a
system
to
determine
the
best
time
to
set
the
savannahs ablaze.





Savannahs
stretch
across
many
parts
of
Africa.
But
scientists concentrated their research on grassland conditions
similar to the Sahel and South Sudan. When wildfires spread
uncontrolled,
the
heat
and
flames
can
cause
damage
on
several levels.





“
Many
components
of
the
ecosystem
can
be
affected.
The biodiversity itself, the soil composition and structure and
gas
emission
and
greenhouse
gas
emission
into
the
atmosphere,
”

said
Cheikh
Mbow,
senior
climate
change
scientist with the World Agroforestry Center in Nairobi, Kenya.




“
Fire is seen as one of the biggest drivers of deforestation
in
some
ecosystems.
And
it
contributes
widely
to
the
reduction of the ecosystem services, which [are] the basis of
most of the livelihoods in Africa in poverty conditions. So we
are
worrying
about
fire
because
of
the
many
impacts
and
implications for the human beings.
”






Fires in savannahs are common.





“
If you look at African images from [a] satellite in the dry
season, it appears that most of the ecosystem, which has some
level of dryness, will have fires on a regular basis. There have
been many attempts in the past, since colonial time actually, to,
sort of, ban fire in our ecosystem, but they never succeeded.
They never succeeded because fire is a tool,
”
said Mbow.




Fire
is
used
as
a
tool
by
local
populations,
for
instance,
when they
’
re gathering honey, clearing land or desiring new
vegetation
growth.
Mbow
says
nearly
all
of
the
fires
in
the
savannahs
are
caused
by
humans.
Nature
plays
a
very
small
role.




“
The conditions in which natural fire can occur [are] when
lightning
happens,
for
instance.
In
Africa,
when
lightning
happens in these tropical areas that
’
s a period during which
we
have
rain.
It
’
s
wet.
When
it
’
s
raining,
that
’
s
the
time
we
have lightning, and it
’
s very unlikely that when it
’
s raining fire
can take place,
”
he said.





With
climate
change,
he
said,
there
’
s
concern
the