WEBVTT FILE

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(bright music)
(birds chirping)

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- [Narrator] We live amongst

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an intricate tapestry of ecosystems.

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Dense misty jungles, vast arid deserts,

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ancient sprawling pine forests,

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all interconnected, all
with a story to tell.

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Understanding these stories helps us

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to understand our planet as a whole,

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how we affect it and how it affects us.

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The scientific community has a wide array

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of methods and instruments to turn to

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when it comes to gathering
data on Earth's surface,

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whether from the ground,
the water, the air,

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or from orbit.

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The orbital perspective
provided by satellites

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allows us to see our
planet across the spectrum,

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both visible and non-visible,

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giving us top-down insight
into the health of our forests,

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temperature fluctuations in our oceans,

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and the extent of glacial
shrinking each year

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due to melting ice and snow.

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Today, Earth's orbit is
bustling with activity,

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home to thousands of satellites

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circling the globe each
day collecting data.

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But over five decades ago,

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let's just say there was much
more room to stretch out.

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In 1972, NASA and the USGS
partnered to launch Landsat 1,

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the first civilian satellite

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designed to image Earth's land surfaces.

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50 years and eight satellites later.

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the Landsat program has
amassed a vast archive of data

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on the surface of our Earth,

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data that's become the
foundation of research

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into a variety of scientific fields.

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From forestry to agriculture,
wildlife conservation,

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and managing natural resources,

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Landsat's ability to look
back across space and time

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and provide consistent,
freely available data

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is an invaluable resource for public good.

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As useful as Landsat data is on its own,

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when combined with data
from other instruments

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such as NASA's GEDI mission,

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it can be a force to be reckoned with.

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NASA's Global Ecosystem
Dynamics Investigation mission

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was launched in December 2018

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and is the first NASA mission

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with the primary objective

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to measure forest vertical structure.

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Orbiting over 250 miles above the Earth

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on the International Space Station,

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GEDI uses LIDAR technology

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to record elevation and
forest canopy structured data

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from the planet's surface.

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GEDI emits near infrared laser pulses

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towards the Earth's surface

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and then measures the time it takes

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for the emitted light to bounce back

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after reflecting off objects,

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such as trees, shrubs,
and the forest floor.

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By analyzing the returned laser signals,

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GEDI provides vertical profiles
of forests and topography,

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a three-dimensional snapshot

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of not just our forests' canopies,

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but also the terrain below,

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critical information for
assessing biodiversity

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and overall forest health.

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And when paired with Landsat's ability

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to look back through time and space,

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GEDI's 3D vertical perspective can give us

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an even more detailed picture
of our planet's forests.

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Researchers in Italy did just that,

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combining Landsat and GEDI data

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to study over 11 million
hectares of forest

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across the Italian Peninsula.

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Like all ecosystems,
forests can be disturbed

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by a variety of factors,
both natural and manmade.

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Wildfires, avalanches,
disease, and deforestation

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can all take a toll on a forest ecosystem.

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The research team
combined over four decades

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of Landsat data with LIDAR data

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captured by GEDI and aircraft

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to not only map when forest disturbances

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across the peninsula occurred,

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but also what impact
these disturbances had

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on forest biomass.

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Their results showed that
following a disturbance,

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it took forests about 15 years to recover,

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much earlier than the
researchers expected.

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As the climate continues to change,

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the frequency of these
disturbances will be on the rise,

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which may have an effect

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on our forest's capacity to absorb carbon.

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Researchers believe that integrating data

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from different remote sensing sources,

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such as Landsat and GEDI,

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could give conservationists a leg up

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in predicting how our forests
bounce back from adversity.

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(bright music)

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The one constant on our
planet's surface is change.

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Our ecosystems are perpetually evolving,

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and for the last five decades,

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Landsat has been in orbit
tracking that evolution.

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The Ghanaian forests of
Western Africa are considered

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a biodiversity hotspot,

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a vast belt of dense forest

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teeming with an assortment
of plants and animals.

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The largest intact track of
the upper Ghanaian forest

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can be found in Liberia,

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where it plays a critical
role in the country's economy.

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Liberia's forests are major sources

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of important commodities,

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such as cocoa, rubber, and palm oil,

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commodities that have,
unfortunately, been a major driver

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in increased land cover change.

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Researchers wanted to know

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how much Liberia's forests had changed

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over a 19-year period,

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and also what effect these changes had

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on the forest ecosystem.

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So, naturally, they turned
to Landsat and GEDI.

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They analyzed Landsat imagery

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collected between 2000 and 2018

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as well as GEDI tree height data

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to map the extent of land
cover change over this period.

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The results showed a significant increase

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in forest fragmentation
over the past two decades.

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Over 14% of dense forest areas,

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which are essential for
biodiversity and carbon storage,

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were degraded

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and GEDI-based measurements
from 2018 showed

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a substantial reduction in
forced height and canopy closure

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when forests transition
to more open classes.

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Researchers believe their method

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of fusing Landsat and GEDI data

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can not only provide the
government of Liberia a roadmap

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to measuring broad changes in
their ecosystems over time,

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but also help to better inform decisions

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on managing their natural
resources going forward.

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Wildfires are often a natural occurrence

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in forests worldwide,

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part of the forest's lifecycle,

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helping to clear out old growth
to make room for new growth.

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But increased drought and
deforestation has in turn led

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to an increase in not only
the frequency of wildfires,

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but also the severity.

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There is, however, an area on Earth

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where wildfires can take on an
even more dangerous quality,

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Chernobyl, site of the
worst nuclear disaster

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in the history of the world.

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Following the disaster in 1986,

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the Soviet government established

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the Chernobyl exclusion zone or CEZ,

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a thousand-square-mile
area surrounding Chernobyl

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deemed too radioactive
for human habitation.

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Almost 40 years later,

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the CEZ is still largely uninhabited,

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home to dense forest

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that has surprisingly
become a haven for wildlife.

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Like other forests,

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Chernobyl's forests too
are prone to wildfires,

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wildfires that can potentially
release hazardous radiation

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into the atmosphere.

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Simulating wildfire
behavior is a necessary tool

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for examining the efficiency
of fuel treatments,

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such as controlled burns,

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but it requires up-to-date maps

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of both fuel types and canopy metrics,

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data not readily available

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for many areas in Ukraine,
including Chernobyl.

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To make up for this dearth of information,

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Ukrainian researchers
developed an approach

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for updating fuel maps

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using freely available
Landsat and GEDI data.

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They fed Landsat data
collected over a 12-year period

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along with GEDI data

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through a machine learning algorithm

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to produce an accurate map of
fuel types and canopy metrics

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across the Chernobyl exclusion zone.

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The researchers believe that the union

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of remote sensing data

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from the likes of Landsat and GEDI

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could provide an effective
method for updating fuel maps,

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particularly in radioactive
areas like Chernobyl,

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where collecting fuel data
can be both impractical

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and downright dangerous.

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These three case studies
make it abundantly clear

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that Landsat and GEDI make
quite the dynamic duo.

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Following four years of service

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aboard the International Space Station,

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NASA announced a pause in GEDI's
mission earlier this year,

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but GEDI's tour of duty
isn't quite up just yet.

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NASA plans to resume
operations sometime in 2024

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with potential plans to continue
collecting data until 2030,

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and when GEDI is back
online, Landsat will be there

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to once again join forces.

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The partnership between Landsat and GEDI

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isn't just about data.

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It's about our planet's future.

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From the dense jungles of West Africa

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to the gentle forested hills of Tuscany,

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Landsat and GEDI are helping us understand

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the complex relationship
between humanity and nature,

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giving us a clearer picture
of our planet's health

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and how we can better protect it,

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allowing us to see the
forest for the trees.

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(bright music)