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We live on a

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water planet. From millions of miles away, Earth

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shines blue, with almost 70% of its surface covered

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in water. But most of that water is in the oceans,

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it’s salty. On Earth, only about 3%

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of water is fresh — the stuff we drink and use

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to feed our crops — and it’s constantly moving:

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Through the atmosphere, soil,

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aquifers deep underground, and even living things. That’s where NASA

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satellites come in. Taking a global look at freshwater provides

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important information about droughts, floods

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and water quality around the globe. The more we know

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about water and its availability, the better decisions we can

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make about how to manage it. From identifying food insecurity

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before aquifers run dry, to pinpointing when

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and where rivers will flood, tracking water from space

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gives us an advantage in using it. For example:

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Looking deep underground, the Gravity Recovery and Climate Experiment,

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or GRACE mission, measured water stored in

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aquifers. When human activity and drought drain aquifers,

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they can be replenished by sufficient precipitation…but they aren’t always.

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GRACE watched how water moved in and out of

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aquifers from 2002 to 2016.

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Closer to our feet, water in the soil changes quickly in response to precipitation.

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We can see soil get wetter in response to rainfall, and about a month later,

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watch as vegetation blooms where the soil is sufficiently

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moist. We can track all of these steps with satellites,

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which help us predict where food insecurity may crop up

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before it becomes a problem. Satellites help us track

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rivers and lakes, too. Reservoirs can become contaminated by

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blooms of algae, which grow in response to fertilizer running off

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from farms and cities. In the upper Midwestern U.S., there are hundreds

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of lakes, so it can be difficult to track them all individually.

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A view from space helps us keep an eye on lakes with blooming algae.

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Rivers are an important source

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of water for communities around the globe, and often, these

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rivers originate as snow high in the mountains.

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Snowpack, or the amount of snow and accumulates on the ground,

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feeds rivers on a seasonal basis.

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Earlier snowmelt can affect how and where water is available for irrigation.

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And as the climate continues to warm, snowpack is disappearing at lower altitudes,

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and what does exist is melting faster.

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Our planet is constantly in motion, with freshwater shifting

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around the globe. Those changes are happening faster in a warming world,

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with precipitation falling in different places, and rivers

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flowing new speeds. NASA’s view

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of where freshwater is, and how it moves, is even

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more important than ever. From deep below

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the ground up into the atmosphere, we’re helping manage their water better.