(bright music) (birds chirping)
- [Narrator] We live amongst
an intricate tapestry of ecosystems.
Dense misty jungles, vast arid deserts,
ancient sprawling pine forests,
all interconnected, all with a story to tell.
Understanding these stories helps us
to understand our planet as a whole,
how we affect it and how it affects us.
The scientific community has a wide array
of methods and instruments to turn to
when it comes to gathering data on Earth's surface,
whether from the ground, the water, the air,
or from orbit.
The orbital perspective provided by satellites
allows us to see our planet across the spectrum,
both visible and non-visible,
giving us top-down insight into the health of our forests,
temperature fluctuations in our oceans,
and the extent of glacial shrinking each year
due to melting ice and snow.
Today, Earth's orbit is bustling with activity,
home to thousands of satellites
circling the globe each day collecting data.
But over five decades ago,
let's just say there was much more room to stretch out.
In 1972, NASA and the USGS partnered to launch Landsat 1,
the first civilian satellite
designed to image Earth's land surfaces.
50 years and eight satellites later,
the Landsat program has amassed a vast archive of data
on the surface of our Earth,
data that's become the foundation of research
into a variety of scientific fields.
From forestry to agriculture, wildlife conservation,
and managing natural resources,
Landsat's ability to look back across space and time
and provide consistent, freely available data
is an invaluable resource for public good.
As useful as Landsat data is on its own,
when combined with data from other instruments
such as NASA's GEDI mission,
it can be a force to be reckoned with.
NASA's Global Ecosystem Dynamics Investigation mission
was launched in December 2018
and is the first NASA mission
with the primary objective
to measure forest vertical structure.
Orbiting over 250 miles above the Earth
on the International Space Station,
GEDI uses LIDAR technology
to record elevation and forest canopy structured data
from the planet's surface.
GEDI emits near infrared laser pulses
towards the Earth's surface
and then measures the time it takes
for the emitted light to bounce back
after reflecting off objects,
such as trees, shrubs, and the forest floor.
By analyzing the returned laser signals,
GEDI provides vertical profiles of forests and topography,
a three-dimensional snapshot
of not just our forests' canopies,
but also the terrain below,
critical information for assessing biodiversity
and overall forest health.
And when paired with Landsat's ability
to look back through time and space,
GEDI's 3D vertical perspective can give us
an even more detailed picture of our planet's forests.
Researchers in Italy did just that,
combining Landsat and GEDI data
to study over 11 million hectares of forest
across the Italian Peninsula.
Like all ecosystems, forests can be disturbed
by a variety of factors, both natural and manmade.
Wildfires, avalanches, disease, and deforestation
can all take a toll on a forest ecosystem.
The research team combined over four decades
of Landsat data with LIDAR data
captured by GEDI and aircraft
to not only map when forest disturbances
across the peninsula occurred,
but also what impact these disturbances had
on forest biomass.
Their results showed that following a disturbance,
it took forests about 15 years to recover,
much earlier than the researchers expected.
As the climate continues to change,
the frequency of these disturbances will be on the rise,
which may have an effect
on our forest's capacity to absorb carbon.
Researchers believe that integrating data
from different remote sensing sources,
such as Landsat and GEDI,
could give conservationists a leg up
in predicting how our forests bounce back from adversity.
(bright music)
The one constant on our planet's surface is change.
Our ecosystems are perpetually evolving,
and for the last five decades,
Landsat has been in orbit tracking that evolution.
The Ghanaian forests of Western Africa are considered
a biodiversity hotspot,
a vast belt of dense forest
teeming with an assortment of plants and animals.
The largest intact track of the upper Ghanaian forest
can be found in Liberia,
where it plays a critical role in the country's economy.
Liberia's forests are major sources
of important commodities,
such as cocoa, rubber, and palm oil,
commodities that have, unfortunately, been a major driver
in increased land cover change.
Researchers wanted to know
how much Liberia's forests had changed
over a 19-year period,
and also what effect these changes had
on the forest ecosystem.
So, naturally, they turned to Landsat and GEDI.
They analyzed Landsat imagery
collected between 2000 and 2018
as well as GEDI tree height data
to map the extent of land cover change over this period.
The results showed a significant increase
in forest fragmentation over the past two decades.
Over 14% of dense forest areas,
which are essential for biodiversity and carbon storage,
were degraded
and GEDI-based measurements from 2018 showed
a substantial reduction in forest height and canopy closure
when forests transition to more open classes.
Researchers believe their method
of fusing Landsat and GEDI data
can not only provide the government of Liberia a roadmap
to measuring broad changes in their ecosystems over time,
but also help to better inform decisions
on managing their natural resources going forward.
Wildfires are often a natural occurrence
in forests worldwide,
part of the forest's lifecycle,
helping to clear out old growth to make room for new growth.
But increased drought and deforestation has in turn led
to an increase in not only the frequency of wildfires,
but also the severity.
There is, however, an area on Earth
where wildfires can take on an even more dangerous quality,
Chernobyl, site of the worst nuclear disaster
in the history of the world.
Following the disaster in 1986,
the Soviet government established
the Chernobyl exclusion zone or CEZ,
a thousand-square-mile area surrounding Chernobyl
deemed too radioactive for human habitation.
Almost 40 years later,
the CEZ is still largely uninhabited,
home to dense forest
that has surprisingly become a haven for wildlife.
Like other forests,
Chernobyl's forests too are prone to wildfires,
wildfires that can potentially release hazardous radiation
into the atmosphere.
Simulating wildfire behavior is a necessary tool
for examining the efficiency of fuel treatments,
such as controlled burns,
but it requires up-to-date maps
of both fuel types and canopy metrics,
data not readily available
for many areas in Ukraine, including Chernobyl.
To make up for this dearth of information,
Ukrainian researchers developed an approach
for updating fuel maps
using freely available Landsat and GEDI data.
They fed Landsat data collected over a 12-year period
along with GEDI data
through a machine learning algorithm
to produce an accurate map of fuel types and canopy metrics
across the Chernobyl exclusion zone.
The researchers believe that the union
of remote sensing data
from the likes of Landsat and GEDI
could provide an effective method for updating fuel maps,
particularly in radioactive areas like Chernobyl,
where collecting fuel data can be both impractical
and downright dangerous.
These three case studies make it abundantly clear
that Landsat and GEDI make quite the dynamic duo.
Following four years of service
aboard the International Space Station,
NASA announced a pause in GEDI's mission earlier this year,
but GEDI's tour of duty isn't quite up just yet.
NASA plans to resume operations sometime in 2024
with potential plans to continue collecting data until 2030,
and when GEDI is back online, Landsat will be there
to once again join forces.
The partnership between Landsat and GEDI
isn't just about data.
It's about our planet's future.
From the dense jungles of West Africa
to the gentle forested hills of Tuscany,
Landsat and GEDI are helping us understand
the complex relationship between humanity and nature,
giving us a clearer picture of our planet's health
and how we can better protect it,
allowing us to see the forest for the trees.
(bright music)