An iceberg is a chunk of ice that has been calved from a glacier. Calving occurs in the spring and summer months , when warmer air causes snow and ice to melt and results in cracks within the ice.  Icebergs range in different shapes and sizes, and are generally comprised of “freshwater ice, soil and rock debris, and trapped bubbles of air”. 
To classify as an iceberg, it must be larger than sixteen feet high and ninety-eight to one hundred sixty-four feet across.  They come in two different shapes, tubular and non-tubular. Tubular icebergs are straighter, with a flat top, while non-tubular icebergs are more round and circular.  Icebergs have small fragments of ice that break off, called bergy bits. They also have growlers, which are even smaller fragments of ice.
Icebergs are mostly found in the western part of the North Atlantic Ocean and in the Southern Ocean, surrounding Antarctica. These icebergs tend to drift over time towards the South Pacific Ocean and South Atlantic Ocean. Other icebergs come from tidewater glaciers from the western side of Greenland. 
On average, 15,000 icebergs are born and 40,000 are calved annually. When icebergs are calved, they drift southward to the Labrador Current, and into the northwestern Atlantic Ocean, posing risks to boats traveling through the North Atlantic.  Between the years 1980 and 2005, there have been fifty-seven instances where vessels have nearly collided with icebergs.
How icebergs are monitored
After the Titanic sank in 1914, the International Ice Patrol (IIP) was formed to monitor the location of icebergs along the Iceberg Alley, and down to the Labrador Current. Originally, ships and aircrafts monitored icebergs, but now satellites that use synthetic aperture radars and infrared imagery monitor the icebergs. The Canadian Ice Services and Danish Meteorological Institute monitor the icebergs, and then assign a letter and a serial number to the icebergs that are over ten kilometers long. These assigned letters correlate to an iceberg’s degree longitude. In addition to the several iceberg-monitoring agencies, GPS and aircraft controls have also made it safer for ships to travel through the North Atlantic. 
Impact on environment
Unfortunately, data has shown that Greenland’s ice sheets are losing more mass each year due to global warming. Scientists have found that temperature increases cause the rate of snowfall to decrease, leading to the melting and calving of ice sheets. This increase in temperature also prevents new icebergs from forming in the fall and winter months. 
The rising temperatures are also causing the water in the Antarctic to warm, melting the glaciers from the bottom. This is also seen as a threat to sea level. However, new research has shown that tiny marine organisms can live in these warmer temperatures and store carbon under water. This reverses global warming by taking carbon out of the atmosphere and slows down the rate of carbon dioxide emission. 
Sea level rise
The amount of ice that floats in the polar oceans is causing the sea level to rise. Normally, floating ice does not affect the sea level, according the Archimedes’ principle; this principle states that, “any floating object displaces its own weight of fluid.” However, since seawater is warmer and saltier, it does indeed displace the nearby floating ice, causing it to rise. This phenomenon has lead to the collapse of the Antarctic ice shelves and the retreat of the Arctic ice. Also, the regional climate is changing. Research shows a 742 cubic kilometer reduction each year, explaining the reasoning behind the Arctic ice’s retreat. 
Impact on Arctic life
Icebergs also impact Arctic life. They are also composed of iron, which causes tiny marine organisms, like plankton, to grow on its surface. The plankton engage in photosynthesis, and as they die, they sink to the bottom of the ocean, taking carbon down with them. Because of this, icebergs are commonly referred to as “geoengineers”. 
Polar bears depend on icebergs for hunting and resting. Since the icebergs have been disappearing, the polar bears have to work harder to find food. As a result, the polar bears struggle to reproduce, and start to die off, making them an endangered species.
In early 2016, 150,000 penguins died in the East Atlantic due to an iceberg that floated nearby. It crashed against the mass of ice housing the penguins. According to the article, the iceberg was about 2,900 square kilometers. The size of this iceberg can be compared to the size of Rome. The iceberg landlocked the penguins and made it harder for them to find food. They would have had to swim sixty kilometers deeper into the water to survive. Unfortunately, the number of penguins living in that area went from 160,000 to 10,000. This particular species of penguins lived in this area for a long time and have been recorded for over one hundred years. Scientists believe that they will eventually die off completely in the next twenty years. 
Other closely related articles in this wiki include:
- Chapman, M. (2008). Icebergs. Climate Change: In Context. Accessed September 30, 2016.
- National Snow & Ice Data Center. (2016). Quick facts on icebergs. Accessed September 8, 2016.
- Martin, E. (2008). Icebergs. The Gale Encyclopedia of Science. Accessed September 22, 2016.
- National Oceanic and Atmospheric Administration US Department of Commerce. (March 4, 2016). What is an iceberg?. Accessed September 8, 2016.
- United States Coast Guard. (2016). Iceberg locations. Accessed September 8, 2016.
- Sosnowski, A. (April 14, 2012). Icebergs still threaten ships 100 years after Titanic. Accessed September 20, 2016.
- Cairoli, S. (September 30, 2016). The effect global warming has on icebergs. Accessed September 30, 2016.
- Mooney, C. (January 11, 2016). The surprising way that huge icebergs slow down climate change. September 30, 2016.
- University of Leeds. (April 29, 2010). Melting icebergs in polar oceans causing sea level rise globally, new assessment finds. Accessed September 14, 2016.
- Malkin, B. (February 13, 2016). 150,000 Penguins die after giant iceberg renders colony landlocked. Accessed September 20, 2016.
Relevant online sources to this wiki article include:
- Ice Glaciers by the NOAA
- Icebergs by the NOAA
- Origins of the Titanice Iceberg by BBC
- Glaciers by the National Snow & Ice Data Center
- The International Ice Patrol (IIP) by the United States Coast Guard
- The International Ice Patrol (IIP) Iceberg Sightings Database by the National Snow & Ice Data Center
- Sea Ice by the National Snow & Ice Data Center