(fire crackling)
- [Narrator] Wildfires,
one of nature's most powerful forces,
capable of reshaping entire landscapes in a matter of hours.
From the arid hills of California
to the dense eucalyptus forests of Australia,
these intense blazes leave a trail of destruction,
challenging firefighters, communities, and ecosystems alike.
But wildfires aren't just about flames.
They're about the cycle of growth, destruction, and renewal.
Though a natural part of many ecosystems,
climate change has amplified their frequency and intensity
the world over, emphasizing more than ever
the importance of better understanding
and managing wildfires.
For over 50 years,
Landsat satellites have been capturing invaluable data,
allowing us to track the health of vegetation,
map burned area, and monitor recovery in burned regions.
So let's explore the ways our guardian Landsat
is used to monitor wildfires
from before the very first spark
to years after the flames have died out.
At the core of each Landsat satellite
are its onboard sensors,
the instruments that give them the ability
to continuously scan Earth's surface for wildfire activity.
Landsats 8 and 9, currently in orbit,
are both equipped with the Operational Land Imager, or OLI,
and the Thermal Infrared Sensor, or TIRS.
OLI captures detailed data across visible near-infrared
and shortwave-infrared wavelengths,
helping scientists assess the distribution, abundance,
and health of vegetation and track changes in land cover,
four factors crucial to understanding wildfire risk.
Healthy hydrated vegetation is less likely to burn,
whereas dry stressed vegetation
is essentially fuel waiting for a spark.
While OLI gives us a bird's eye view
of land cover and vegetation health
TIRS measures surface temperatures
critical for detecting heat anomalies,
which can help spot fires as they start.
It's this combination of OLI's vegetation data
and TIRS' heat detection
that allow Landsat to be such a powerful tool
for wildfire management.
Landsat satellite's onboard instruments
coupled with their ability to revisit
the same location every eight days,
provide consistent and reliable data,
giving scientists tools to characterize the fire lifecycle
beginning before they ignite
to well after they've been successfully snuffed.
One of the most effective ways to manage wildfires
is by understanding and controlling the vegetation
or fuel that powers them.
Vegetation that becomes dry or overgrown can act as tinder,
intensifying fires when they ignite.
Landsat satellites play a crucial role
in monitoring these fuel loads
and helping fire managers reduce the risk
of large uncontrollable wildfires.
Fuel management strategies rely on accurate data
about vegetation health, moisture levels, and structure,
which can be gathered from Landsat's onboard sensors.
Landsat's multi-spectral capabilities
allow scientists to assess
various characteristics of vegetation across vast areas.
With this data, they can classify vegetation
into different fuel types,
each with a different likelihood of burning.
And Landsat imagery can show
how vegetation changes over time,
detecting areas that are becoming drier or denser,
providing information that can guide actions,
such as controlled burns or mechanical thinning.
As climate change continues to influence
the behavior of wildfires,
Landsat's long-term consistent data
offers fire managers the crucial tools
needed to safeguard forests, communities, and ecosystems
from their destructive force.
Once a wildfire ignites,
tracking its progression is critical
for understanding its impact on ecosystems and landscapes.
Landsat's ability to map burned areas
has been a game changer,
allowing scientists to assess fire patterns
more accurately than ever before.
A new approach developed by researchers
uses dense time-series data from Landsat
to create highly detailed maps of burned areas.
This method goes beyond simply spotting active fires.
It reveals the true extent of burned land
even after the flames have been extinguished.
The key to this innovation is an advanced algorithm
that uses data from Landsat's visible,
infrared, and thermal bands
to identify areas that have been burned.
By comparing images from before and after the fire,
the algorithm can detect changes in vegetation,
soil, and surface heat,
giving a precise picture of where the fire spread.
The result?
A more accurate estimate of the total area burned,
identifying 36% more burned area than previous methods
in key regions like the western US
where fires are most common.
Landsat's detailed burned area maps
not only help researchers understand
how fires affect the landscape,
but they also support long-term monitoring
of fire prone ecosystems, providing invaluable data
for improving wildfire response strategies
and protecting both natural and human environments.
The story doesn't end
once a wildfire's flames have been quenched.
In fact, it's just the beginning.
Despite the charred landscapes
left behind in a wildfire's path,
nature has a remarkable ability to recover
if we give it the chance.
This is where Landsat's long-term data record
really pays off,
helping scientists monitor this recovery process
by providing detailed, consistent imagery
that tracks how forests and ecosystems
rebound from fire damage.
In 2019, a team of researchers used Landsat imagery
to study the recovery of forests damaged by wildfire
in western North America.
The study looked at 12 wildfires
that occurred between 2000 and 2007
across three different forest types:
ponderosa pine, mixed conifer, and conifer-oak-chaparral.
Using LandTrendr, a Landsat-based tool
for analyzing changes in land cover over time,
the researchers analyzed decades of Landsat imagery
to track how these burned areas changed over time.
They focused on something called the normalized burn ratio,
or NBR, an index calculated from Landsat's infrared bands
sensitive to both burn severity and vegetation regrowth.
By observing how NBR changed year after year,
the team could measure forest recovery rates.
The results showed
that although forests are remarkably resilient,
recovery takes time.
On average, five years after a fire,
forests had recovered about 30 to 44%
of their pre-fire vegetation cover.
After 10 years, this increased to 47 to 72%,
and by 13 years post-fire, recovery ranged from 54 to 77%.
As wildfires become more frequent and severe
due to climate change,
studies like this one are more important than ever,
helping us understand how our forests
might change in the future
and how we can better manage and protect
these vital ecosystems,
all made possible by the continuous reliable data
provided by the Landsat program.
While the current generation of Landsat satellites
has revolutionized our ability to monitor wildfires,
the future holds even more promise.
Landsat Next, scheduled to launch in the coming years,
will push the boundaries
of satellite technology even further.
With improved spatial and temporal resolution,
Landsat Next will provide more frequent observations
of wildfire-prone regions.
And Landsat Next enhanced thermal imaging capabilities
will allow for more precise temperature readings
and be able to detect even smaller hotspots,
possibly providing earlier warnings for potential wildfires.
Landsat Next will also feature additional spectral bands,
allowing for even more detailed analysis
of vegetation health and fire damage.
Whether it's predicting fire risk or monitoring recovery,
Landsat Next promises to be a game changer
in wildfire management.
Wildfires are an inevitable part of many ecosystems,
but with the right tools,
we can better manage and mitigate their impacts.
For decades, the Landsat program has given us the power
to monitor the Earth from above,
providing critical data on fire risk,
detection, and recovery.
As climate change evolves
and wildfires become an increasingly pressing global issue,
the insights gained from Landsat
will be more important than ever.
From predicting where the next fire might spark
to watching nature's incredible recovery unfold,
helping us better understand and protect our world.