Readers ask about sea level rise, the universe’s first stars and more

On the rise

A thinning, accelerating ice stream in Greenland’s interior could contribute nearly 16 millimeters to global sea level rise by 2100, more than six times as much as previously thought, Nikk Ogasa reported in “Greenland is hemorrhaging ice” (SN: 12/17/22 & 12/31/22, p. 7).

Reader Leslie Hruby wondered how local sea levels will be affected as an ice sheet melts and the land underneath rebounds.

“The immense weight of the ice can depress the Earth’s crust, just like a heavy object placed on a soft mattress,” Ogasa says. When the ice retreats, the unburdened ground rises back up.