Hi, my name is Tom Neumann. I'm at NASA Goddard Space Flight Center, where I’m the project scientist for the ICESat-2
mission.
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.
During those melt events, more than half of the ice sheet surface was melting.
That led to larger-than-average losses for the whole ice sheet.
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.
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
the Greenland ice sheet melt each year, all of that melting ice and snow runs off as liquid water into the ocean and raises
the sea levels globally.
Of course, there's so many people that live very close
to sea level
and so the changes in the Greenland ice sheet impact them directly.
The second way changes in the Arctic impact folks globally is through the changing energy balance as the sea ice grows and
shrinks each year.
Sea ice is very reflective
and solar radiation
Bounces off of the sea ice and is reflected back into space.
As sea ice melts, as it has this summer in record amounts,
the darker ocean water is exposed.
Ocean water can absorb sunlight and changes both the temperature of the ocean and the overlying atmosphere.
Those changes in the temperature of the ocean in the atmosphere.
Cause changes in the weather globally through changes in the position of the jet stream or how high and low pressure cells
move around the planet.
One of the things we hope that people take away from learning about changes in the Arctic sea ice in the Greenland ice
sheet
Is that the polar regions are some of the most rapidly changing parts of the planet.
NASA's ICESat-2 Mission launched in September 2018
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.