- 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)