Additionally, as the ice compacts over time, tiny bubbles of the atmosphere—including greenhouse gases like carbon dioxide and methane—press inside the ice.

Most bergs formed in Canada and Greenland stay in the eastern Arctic, eventually being carried into the Atlantic via Davis Strait and melting away.

• The other kind of arctic ice is pack ice.
• Ice that forms each winter and melts each summer is known as annual ice, and is usually about six feet thick.

Bergs also form from Antarctic glaciers. Based on their sizes, they are given different names, such as growler and bergy bit. The other kind of ice is sea ice, also called pack ice. As the surface temperature continues to drop, the ice forms a solid layer and is then called pack ice.

The most basic difference is that sea ice forms from salty ocean water, whereas icebergs, glaciers, and lake ice form from fresh water or snow. Sea ice grows, forms, and melts strictly in the ocean. Glaciers are considered land ice, and icebergs are chunks of ice that break off of glaciers and fall into the ocean.

Unlike ice shelves, glaciers are land-based. While glaciers are defined as large sheets of ice and snow on land, ice shelves are technically part of the ocean.

The oldest continuous ice core records extend to 130,000 years in Greenland, and 800,000 years in Antarctica. Ice cores are typically drilled by means of either a mechanical or thermal drill.

Researchers used data on Earth’s orbit to find the historical warm interglacial period that looks most like the current one and from this have predicted that the next ice age would usually begin within 1,500 years. They go on to predict that emissions have been so high that it will not.

The world’s largest iceberg — thrice the size of Delhi — has broken off from Antarctica last week. It split off the western side of the Ronne Ice Shelf in Antarctica’s Weddell Sea, the European Space Agency (ESA) informed.