The Science of Wildfires: Why They're Getting Worse | WSJ

- It was just a fireball
and traveled so fast.

- I just saw flames all up
on the hill behind my house.

- It was Armageddon I'll tell you,

the fire coming in and
burning all around us,

- [Narrator] Alaska,
Arizona, California, Montana,

Oregon, Australia, Brazil,
Canada, Greece, Russia.

These are just some of the places

where in recent years, wildfires
have raged out of control.

NASA satellites detect

more than a million large
fires worldwide every year.

- The Western United States, for example,

has seen larger fires in each
of the last several years

and more intense burning,

and many times as fire spread faster,

making them more difficult
to put out and more dangerous

for the communities who
live in that vicinity.

- [Narrator] In many
cases, the blazes are set

by human activity,

but sometimes policy fuels the flames too.

Consider California,

the state's forests are overgrown in part

because of past federal policies
of putting out wildfires

rather than letting them burn.

Some of these policies were enacted

in response to a devastating fire in 1910,

in which millions of acres
burned more than 80 people died,

years passed and suppression
became the go to strategy

for dealing with fire.

- [Narrator] Ignition,
It only takes a minute

to wipe out a century.

- [Narrator] initiatives like
Smokey Bear urged Americans

to help prevent forest fires.

- Only you can prevent forest fires.

- In 1974, Congress passed

the Federal Fire
Prevention and Control Act

in an effort to save lives,

and that plan worked.

Around that time
according to the act fires

of all types killed more
than 12,000 people each year.

Today according to the
U.S Fire Administration,

the death toll is lower,

but-

- Part of the reason
we see increasing fuels

and increasing extreme fire behavior

is that we have a legacy
of putting fires out

and allowing fuels to
grow permitting fires

when they do start to get out of control,

- [Narrator] Overgrown
forests have an abundance

of small and medium trees
known as ladder fuels,

which can make fires more dangerous.

- Ladder fuels would allow
a surface fire burning

often slowly along the ground
to transition into the canopy,

or it can spread more rapidly.

And when those trees are burning,

the embers that are blown
by the wind can ignite

the neighboring trees,

they can also be spread further downwind.

- [Narrator] That's part of the story

of California's 2018 fire season.

The deadly campfire
was fed by dry weather,

fast winds and ladder fuels.

According to recent research,

20 million acres of forest land,

or nearly 20% of California would benefit

from what's known as fuel treatments.

Land managers can limit the
fuels that could create large,

fast moving fires in several ways,

including getting out vegetation,

think logging or clearing brush,

prescribed burns where small
fires are set deliberately,

or letting natural wildfires

in unpopulated areas
run their course under

the watch of local firefighters.

But clearing out brush can be expensive

and labor-intensive.

First since many of these
trees are small in diameter,

so they don't have
commercial value as timber

and there's little financial
incentive to remove them.

And federal policies
have historically favored

putting out fires as soon as
they start to keep people safe.

- Maintaining that balance
of different ecosystem types

IN different fire
frequencies is more difficult

when we move into areas with
more dense human populations.

And so the wild land
urban interface is really

where these two challenges meet,

where people are living in
communities against landscapes

that historically have had fire activity.

Those are landscapes that
are very difficult to protect

when fires do start.

- [Narrator] One of the factors affecting

California's wildfire season
is new housing construction

in fire prone areas.

Climate change is adding
to the problem too.

- Where fuels are abundant today
and where climate change is

leading to warmer and drier conditions,

we are already seeing more
extreme fire behavior.

- [Narrator] According
to recent Federal Data,

the last decade was the warmest on record.

During the summer of 2020
fires burned in the Arctic,

as parts of Siberia broke the record

for the highest temperature
ever recorded above

the Arctic circle.

- They're almost always too
cold and too wet to burn.

So as those landscapes,

which are warming three
times faster than the rest

of the planet, continue to warm and dry,

we certainly expect to see more fires

in those remote landscapes
directly in response

to climate change.

- [Narrator] In August of 2020, wildfires

most of them sparked by
lightning raged out of control

across California.

Earlier in the year,

state officials had warned
of high fire danger caused

by a dry winter and warm spring.

It's a pattern scientist
generally attribute

to climate change.

In May, the mountain
snowpack in California,

Sierra Nevada was just 13% of
normal and it's not just 2020,

half of California's 20
most destructive wildfires

have happened since 2015.

Across the forests of Southeast Australia,

NASA mapped more fires
between 2019 and 2020

than they had in the last 16 years.

The fires were fueled by
extreme heat and drought,

hotter, drier weather sucks
moisture out of the trees,

grasses, and other fuels
making them more flammable.

And this is making fire management
all the more complicated.

- So as conditions that
allow wildfires to spread

are lasting longer across the
United States and elsewhere,

there's a shorter and shorter window

where active management
could happen under conditions

that wouldn't risk fires
escaping and spreading

into lands as a wildfire.

- [Narrator] That means
fighting fire with fire

might not be an option for
certain regions anymore.

So to help with wildfires,

researchers are working on algorithms

to improve forecasting.

- [Doug] If we can
anticipate the timescales

and the locations where
fires are most likely,

we have the best chance
of trying to mobilize

and prepare resources to anticipate fires

and make up more timely
decision about which fires

to put out and which to let burn.

(soft music)