Ask a Scientist
These articles provide answers to frequently asked questions related to Earth's frozen realms. Questions range from general background information and detailed science processes to the data gathered and archived at the National Snow and Ice Data Center (NSIDC) and its data management programs including NOAA@NSIDC, the NASA NSIDC Distributed Active Archive Center (DAAC), and the Exchange for Local Observations and Knowledge of the Arctic (ELOKA). If you have a question that is not answered here, please contact NSIDC User Services.
Filter by:
Depending on who is using the data and to what end, sea ice data can be misread and even used in disinformation campaigns about Earth’s climate. Here, NSIDC discusses five common misuses of sea ice data.
After decades of watching Arctic sea ice extent drop as climate warms, scientists are eager to know if climate change has finally caught up to Antarctic sea ice. Several recent studies explore that idea using statistical analysis of sea ice extent data from the NASA NSIDC Distributed Active Archive Center (DAAC) and the National Oceanic and Atmospheric Administration (NOAA@NSIDC).
While the Northeast Passage is never guaranteed to be ice free, a 2023 study identified the time of year when ships are the likeliest to succeed in negotiating the route: mid-September.
Most mountain glaciers outside the polar regions are losing ice, but in the Karakoram Range, glaciers have experienced modest gains. Glaciologists have proposed multiple explanations, currently favoring weather patterns unique to the region. Glaciologists have also pondered how long the anomaly is likely to persist in a warming climate.
The term “ice-free” is based on a threshold for sea ice extent: the area of ocean with at least 15 percent sea ice concentration. A consensus has emerged among scientists that the Arctic Ocean is effectively ice free when its sea ice extent falls below 1 million square kilometers (390,000 square miles).
Sea level rise from ice sheet loss will not be uniform and, ironically, sea levels near melting ice sheets will likely fall. Scientists anticipate that sea level will rise fastest along some densely populated coastal regions in the tropics and mid-latitudes.