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The reason that we as humans care
 about climate change

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is that it affects
 not just the temperature,

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but a whole bunch of other things
 that we care about.

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It affects soil moisture, 

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which in turn affects our ability
 to grow the things that we eat.

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It affects cloud cover.

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It affects rainfall patterns. 

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It increases drought risk in some regions
 and decreases it in other regions.

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Understanding our changing climate
 on a planet with incredibly complex

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and interconnected systems
 is a massive scientific undertaking.

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And climate scientists like Kate
 Marvel are using the data collected

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by satellites from around the world
 to improve the power of climate models.

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If we want to make better decisions about 

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where we live, understand
 the changing impacts of hurricanes

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or improved predictions of fire seasons,
 we need evolving climate models.

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We don't have any observations
 from the year 2050, from the year 2100,

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but we can use our best knowledge
 of physics and chemistry

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and how the Earth system works
 in order to look at the impact

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of different emissions
 trajectories, different policy scenarios.

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Climate models provide a view
 into our future from our globe

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to our own communities.

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As models advance, as they're tasked
 with predicting the nature of the weather

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and the clouds over
 smaller and smaller scales,

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they're being asked
 tougher questions like, Well, 

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what kind of clouds are happening
 over those small scales and how often

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and how heavily are they raining? 

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We expect roughly on really,
 really large scales

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climate change is making wet
 regions wetter and dry regions drier.

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But at the same time, it's shifting
 the circulation of the atmosphere.

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So the locations on a very, 

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very large scale of those wet
 and dry regions are changing.

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Climate models are composed of
 lots of different calculations on the

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different behaviors of our atmosphere,
 our land and our oceans.

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To accurately represent the natural world
 they need massive amounts

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of satellite data over decades from NASA's
 Earth observation

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fleet and its partners around the world.

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Satellites like the Global Precipitation
 Measurement Mission

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provide valuable rainfall data 

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on daily to seasonal timescales
 for the past 20 years.

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And it's that information,
 along with a suite of other

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data that go into climate
 model development.

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Currently, the GPM microwave imager
 radiance data are used to generate

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initial states of NASA climate models
 and to guide climate model

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solutions to be close to real states
 by applying data assimilation techniques.

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Data assimilation is the process
 of combining many different sources of

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Earth observations into models to improve
 how we represent the Earth system.

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Assimilating GPM microwave imager data

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improved intensity and locations of storms

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and precipitation
 calculated by the climate models.

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And once a climate model is developed,
 it's tested over and over because, well...

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All models are wrong, 

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but some models are useful,
 so they're always going to be incomplete.

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They're always going to be a not exact
 representation of the real world.

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But we want to make sure that they are
 capturing important aspects of the Earth

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so that we can treat them
 as credible going forward.

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Typically, what happens is when you modify
 one part of the climate model,

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other parts accidentally change.

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It's kind of like the Whack-A-Mole game. 

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By hitting it down, we're improving it,
 we're killing the error, we're decreasing

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the problem existing in a model,
 but another area pops up.

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And that is why NASA observations
 of the Earth from space, the air and

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the ground are critical to understanding
 how our Earth system works.

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Observations help improve the modeling
 for our future here on Earth,

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with new capabilities
 to expand our knowledge.

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NASA is launching satellites
 and coordinating missions, like GPM,

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giving us that long term, really accurate
 satellite record of what's been going

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on, not just the temperature rising,
 but of various aspects

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of the climate changing. 

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So precipitation and cloud cover
 and soil moisture,

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and a whole bunch of different
 climate variables that people care about.

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Continuing key observations of the Earth
 is really important

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to see how our atmosphere, land
 and oceans are changing over time.

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A long term record,
 combined with cutting edge observations

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from the new NASA
 Earth System Observatory, will continue

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to push boundaries to better understand
 our ever changing Earth.