Wildfires 101: How NASA Studies Fires in a Changing World

When you think of wildfires,

you may think of destruction.

Skeletal forests, property lost
and lives forever changed.

But fires can also bring rejuvenation.

They can renew ecosystems,
nourish the soil, and foster new growth.

But climate change is causing these fires
to burn larger, longer, and more often.

These larger and more frequent
fires damage ecosystems,

disrupt communities, and can even
influence the climate.

So, understanding the basics of wildfires

and how they're impacted
by climate change,

is key to our ability to predict
where and when fires are likely to occur.

As well as remotely detect
and track wildfires once they ignite,

and ultimately mitigate
their impacts on human health

and the environment.

This is Wildfires 101.

The first thing you should know,

is that wildfires
require three key ingredients:

fuel to burn, the right conditions,
and a source of ignition.

But what does that actually mean?

So fuel - like needles, leaves,
or wood on the forest floor,

is rarely a fire's limiting factor.

And the conditions that are favorable
for fire like hot, dry, and windy days,

are becoming more and more common
as our climate changes.

Under these “fire weather” conditions,

fuels dry out
and become more susceptible to burn.

As for source of ignition?

Well, most of the wildfires

that NASA detects
from space are started by people.

Others, usually in the Arctic and boreal
regions, are ignited by lightning strikes.

NASA can track these conditions
and inform land managers

when an area appears prone to wildfire.

Every day, NASA is able
to detect thousands

of new fires from space.

Along with our partners at NOAA,

we use both polar orbiting
and geostationary satellites

to get insight as to the structure
and evolution of a fire.

Geostationary satellites remain
fixed in relationship to the globe,

giving us new images of one hemisphere
every 5 to 15 minutes.

However, the resolution is usually coarser

than that of polar orbiting satellites,

which will pass over a fire twice per day.

From over 500 miles above the Earth,

these orbiting satellites will detect
and characterize thermal anomalies:

locations on the Earth's surface
that are hotter than their neighbors,

that can indicate burning

associated with new
or existing fire events.

Importantly, these instruments
can detect fires at night -

a time when wildfires typically lay down
and smolder.

Since the majority of large wildfires
lasts for multiple days,

the ability to track them both day
and night is instrumental

to helping land managers
combat the blazes.

But it's not just the fire itself
that's dangerous.

Wildfire smoke can travel
for thousands of miles,

having the ability to blanket
large swaths of a continent

from a single wildfire.

Smoke from wildfires can reach
high altitudes -

between 3 to 6 miles -
and travel with prevailing winds.

This smoke can linger
in the air for several weeks,

changing the chemistry
of the atmosphere

and reducing the amount of sunlight
reaching the surface.

Smoke that gets trapped near the ground

severely impacts the air quality
in surrounding communities,

and poor air quality can last for months

as large fires continue to smolder

even after the fire itself
has been contained.

Climate change is not only impacting

the size and intensity of wildfires,

but also their frequency in some regions.

NASA has over 22 years of daily fire data
to track wildfire trends.

This is important to get a sense
of how fire regimes,

the historical frequency of wildfires
in a region, are changing over time.

Understanding an ecosystem’s
fire regime is important

because in many instances,
wildfire is essential

to maintain a mixture of younger
and older vegetation.

However, when fires occur too frequently
or with increased severity

it can have devastating effects

like destroying habitat, changing
soil chemistry, and clogging waterways.

Not to mention releasing greenhouse gases

like CO2 and aerosols into the atmosphere.

NASA can study wildfire’s impact
on the landscape

by measuring burn scars,

as well as tracking vegetation loss
and rate of regrowth.

Having an accurate assessment
of a landscape post-fire

is a key part of understanding
how ecosystems recover over time.

NASA’s ability to not only track wildfires

but also the conditions that lead to them,

is essential to our ability to mitigate
their impacts.

We're working with land managers

and those on the front lines
to give them the tools,

including near real-time data,

to help them make decisions
to minimize the risks

and plan for the future.

English Captions: Shereen Medhat
QA: Thais Barros