Burning up

The skies outside my home near Whistler, BC, are blanketed in smoke from all the fires south of the border. With this constant reminder of forest fires hanging over our heads, I thought I would re-post this piece I co-wrote last year with Mike Flannigan, Director of Canada Wildfire at the University of Alberta, for the Our Future On Earth 2020 report... (to chase down the references, open the PDF linked here).

Burning Up

Fire on the planet today is different than it has
ever been before.16 Climate change is increasing
wildfire hazard over the majority of the planet,
while a growing human presence is creating more
sources of ignition and putting more infrastructure
in the path of flames. Policies of fire suppression
have made some forests more prone to larger
fires. And the intentional clearing of rainforests for
agriculture with fire is altering those landscapes
forever – and creating deadly smoke.

There isn’t necessarily more fire: wildfire activity
today is actually less than it was 100 years
ago. Nor is fire inherently bad. Fire is a natural
phenomenon in ecosystems from temperate
forests to grasslands; some pines require the
heat of a wildfire to melt their resin and open
their cones.

But fire becomes a concern when it burns
our homes, rapidly and dramatically shifts
ecosystems, or chokes the air we breathe. And it
is doing more of that. In 2019, a dramatic number
of fires in the Amazon – a region that saw little fire
before humans arrived – grabbed media headlines.
Indonesian skies turned red from intentionally
lit fires. Australia was ravaged by bush fires in
the midst of an unusual drought. And the Arctic
Circle saw unusually high occurrences of fire
from Siberia to Greenland. California’s 2018
Camp Fire was the costliest ever in the world
(at US$16.5 billion in total losses), and tragically
killed 85 people. Countries around the
Mediterranean Basin are under the stress
of catastrophic fires every summer.

Climate change has been identified as part of
the reason. Warmer air pulls moisture out of
vegetation – creating drier fuel – and feeds winds
to fan flames. Each degree of air warming is
thought to increase lightning strikes by about
12%.17 As mountain ice packs melt, there is less
water to feed landscapes over a long summer.
Globally, the length of the fire weather season
has increased by more than 18% between 1979
and 2013.18 The majority of the burned area
happens over a few short days of extreme fire
weather – extreme weather that is becoming
more common.

Climate models predict that many dry areas
will get drier. And while increasing rain in some
regions might counteract fire hazard, that isn’t
always the case: more rain in winter and/or early
spring, for example, can create more vegetation
prone to burning in a later, drier summer.
Global models predict that, overall, more
regions will see an increased fire probability
than a decreased one.19

Fire management is another part of the
explanation for our current vulnerability. A kind
of “war against fire” was initiated in the early
20th century, predominantly in the United States:
authorities viewed wildfire as a blight and adopted
policies to stamp it out early. Decades of intensive
fire suppression changed some landscapes
dramatically, altering traditional patchworks of
different ages and types of vegetation to a more
uniform forest prone to larger conflagrations.
As a result of both climate and policy, the annual
burned area in the western United States
increased more than fivefold from 1985 to 2015.

Over the longer term, and globally, land use
change has been the dominant determinant of
fire regimes.20 Fire has remained relatively steady
over the past 1,000 years or so, with a dramatic
uptick from the 19th–20th century as farmers
and settlers used fire to clear land during the
Industrial Revolution. The total area burned then
declined in the first decades of the 21st century,
thanks to less-fire-prone agriculture taking
the place of tropical savannas and grasslands.

Models predict that climate change – in particular
increasing temperatures – could become
a prevailing force determining fire activity
in the coming decades.

The amount of carbon dioxide released by wildfires
can be striking. The summer 2019 Siberian
wildfires, which burned an area larger than
Denmark, produced more CO2 than tens of millions
of cars do over a year. If a forest regrows, over the
long run a wildfire can be carbon neutral. But in
Siberia and elsewhere the burning of peat – banked
carbon that has been accumulating for thousands
of years – or the thawing of permafrost leads to
a net release of greenhouse gases, upsetting
the balance. The replacement of rainforests with
agriculture also hinders the planet’s ability to store
carbon long term.

Despite some media reports, razing the Amazon
does not affect the “planet’s lungs”: vegetation
is neutral when it comes to oxygen, absorbing as
much as it emits. What it does do is affect human
lungs, through the production of soot and smoke.
Fire emissions are responsible for more than
300,000 premature deaths annually from poor air
quality.21 There are plenty of reasons to preserve
rainforest ecosystems; saving people from air
pollution is one of them.

A more sustainable planetary system will still
have fire, and plenty of it. Humans need to learn
to live with that, and to better manage the risk –
in part by dialling back climate change.