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Hi, my name is Tom Neumann. I'm at NASA Goddard Space Flight Center, where I’m the project scientist for the ICESat-2

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mission.

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This year we've had two really large melt events: one in the middle of June and the other one in the beginning of August.

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During those melt events, more than half of the ice sheet surface was melting.

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That led to larger-than-average losses for the whole ice sheet.

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It's not yet a record loss year for the ice sheet, but it's going to be close once we analyze this year's data.

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We often say that what happens in the Arctic doesn't stay in the Arctic and there's two reasons for that. One is that as

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the Greenland ice sheet melt each year, all of that melting ice and snow runs off as liquid water into the ocean and raises

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the sea levels globally.

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Of course, there's so many people that live very close

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to sea level

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and so the changes in the Greenland ice sheet impact them directly.

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The second way changes in the Arctic impact folks globally is through the changing energy balance as the sea ice grows and

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shrinks each year.

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Sea ice is very reflective

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and solar radiation

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Bounces off of the sea ice and is reflected back into space.

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As sea ice melts, as it has this summer in record amounts,

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the darker ocean water is exposed.

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Ocean water can absorb sunlight and changes both the temperature of the ocean and the overlying atmosphere.

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Those changes in the temperature of the ocean in the atmosphere.

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Cause changes in the weather globally through changes in the position of the jet stream or how high and low pressure cells

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move around the planet.

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One of the things we hope that people take away from learning about changes in the Arctic sea ice in the Greenland ice

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sheet

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Is that the polar regions are some of the most rapidly changing parts of the planet.

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NASA's ICESat-2 Mission launched in September 2018

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So we have a new tool in space to understand our changing Arctic and Antartic in ways that we haven't been able to before.