Our Dynamic Earth

Narration: Katie Jepson

Transcript:

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Across our planet, sea levels are on the rise.

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And while our changing climate is a huge driver,

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the movement of land, itself, is also an important factor.

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Around 20,000 years ago, ice sheets covered large areas of our planet,

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In many places, the weight of these massive ice sheets pressed down

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on the planet’s crust and the viscous mantle underneath.

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This weight caused the surrounding land to rise,

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and the sea levels to fall relative to that rising land.

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Overtime, these ice sheets began to retreat

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as part of Earth’s natural cycle of glaciation and melt.

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and as a result, this land began to rebound.

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Land rose up, and previously uplifted land sank, or subsided,

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causing the sea level to rise relative to the ground.

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This adjustment of the land in many previously glaciated regions

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continues to this day,

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particularly in areas like the East Coast of the United States.

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Today, if we were to travel to a region like Greenland,

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where massive ice sheets are now retreating due to a changing climate,

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we can see the land readjusting in the same way to the lessening load.

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This also alters the shape of corresponding ocean basins,

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leading to additional subsidence along coastlines.

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Subsidence also can result from human activity.

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For example, we can see that many coastal cities rely on underground aquifers for fresh water.

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However, when water is extracted, it causes sediment to compact

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and the ground above to subside.

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This leads to additional sea level rise for these communities.

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We live on a dynamic planet that is constantly in motion.   

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And understanding the many drivers of sea level rise is critical

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to anticipating and adapting to our ever-changing home.