A 60-mile long slab of ice, known as B-9B, nudged against a tongue of glacier sticking out from Eastern Antarctica in the last month, causing a 965 sq mi iceberg to break off from the Mertz glacier, which is floating in the ocean. That 965 sq mi iceberg is the size of Luxembourg.
This isn’t necessarily a global warming-related event. Iceberg B-9 calved from Antarctica back in 1987 and has been floating around the continent since. Chance allowed it to hit the Mertz glacier 23 years later.
The event could have implications on global ocean currents, however. Dense, salty water forms in the area of the collision. This dense water sinks toward the ocean floor and begins traveling around the globe. It takes about 1000 years for a volume of water to tranverse the entire circuit. The downwelling in the collision area is one of the drivers of the entire conveyor belt, as it is known. Since glaciers are frozen fresh water, and since the area around the Mertz glacier can now fill up with sea ice, the formation of the heavier salt water could be slowed. That could have effects on the remainder of the global ocean circulation.