Snipfact:

    Global warming  is melting the world’s ice shelves. As ice floes shrink and drift apart. Polar bears are forced to swim up to 97 km (60 miles) between them in search of prey. Some never make it and drown.

    During World War II, Lord Mountbatten led a programme to build artificial icebergs to use as aircraft carries, but the project, codenamed Habbakuk, was abandoned.

    At least 500 incidents have been recorded of ships striking icebergs. The worst disaster involving an iceberg happened when the Titanic struck one on 14 April 1912 and 1,503 people died. Cruise ship MS Explorer struck an iceberg in the Antarctic and sank on 23 November 2007. All 154 Passengers and crew were rescued.

    About 10,000 to 15,000 new icebergs are formed every year. The Process is called “Calving”. The air trapped in icebergs is “harvested” and sold for use in drinks. It may be 3,000 years old.

    One of the biggest icebergs of recent times, known as B-15, broke away from the Ross Ice Shelf, Antarctica, in March 2000. It had an average length of 295 km and width of 37 km, making it about the size of Jamaica!

  Icebergs less than 1 m high and 5 m wide are known as growlers because of the noise they make. Iceberg larger than growlers are called bergy bits; then they are graded small, medium, large or very large icebergs are those measuring more than 75m high and 213 m wide.

  An iceberg is a large piece of ice that has broken away from a glacier or ice shelf. In the North Atlantic most came from Greenland glaciers, and in the South Atlantic from Antarctica. The word iceberg probably comes from the Dutch ijsberg or ice hill. Icebergs float because they are made of fresh water. Which is less dense than sea water.

    Seven-eighths of an iceberg is below the surface of the sea, hence the expression  “the tip of the iceberg”, which means that more is hidden that can be seen. The tallest iceberg measured was 168 m high. It was seen in 1958 off Greenland and was as tall as a 50-storey skyscraper.

  Ocean is the term used for the world’s sea water, expect for landlocked seas such as the Caspian.   More than 70 percent of the planet’s surface is occupied by oceans – the Pacific Ocean alone is more than 25 percent larger than the planet’s entire land area. Smaller divisions of some oceans are separately named as seas. Pacific Ocean – 166,240,000 sq km Atlantic Ocean – 86,560,000 sq km Indian Ocean – 73,430,000 sq km Arctic Ocean – 13,230,000 sq km South China sea – 2,974,600 sq km Caribbean sea – 2,753,000 sq km Mediterranean Sea – 2,510,000 sq km Bering Sea – 2,261,000 sq km Gulf of Mexico – 1,542,985 sq km Sea of Okhotsk – 1,527,570 sq km East China Sea – 1,249,150 sq km Sea of Japan – 1,012,945 sq km Andaman Sea – 797,700 sq km Hudson Bay – 730,380 sq km

  There are about 20 deep trenches in the world’s oceans. The eight deepest would be deep enough to submerge Mount Everest. The Marianas Trench is the deepest point in the deepest ocean, the Pacific . It was discovered in 1951 and explored in 1960 when Jacques Piccard (Switzerland) and Donald Walsh (USA) descended in their bathyscaphe Trieste 2 to a depth that has since been calculated as 10,916 m (35,813 ft).

    The Pacific Ocean is the deepest ocean. Its greatest depth is 10,924 m (35,837 ft) with an average depth of 4,028 m (13,215 ft). The Indian Ocean is 7,455 m (24,460 ft) at its deepest point and has an average depth of 3,963 m (13,002 ft). The Atlantic Ocean comes next with a greatest depth of 9,219 m (30,246 ft) and an average depth of 3,926 m (12,880 ft).

  The coastline of Canada, including all its islands, is more than six times as long as the distance round the Earth at the Equator (40,076 km). Greenland (Kalaalit Nunaat) is not in this list as it is part of Denmark, not a separate country, but its coastline is 44,087 km long.   1 Canada – 265,523 km 2 USA – 133,312 km 3 Russia – 110,310 km 4 Indonesia – 95,181 km 5 Chile – 78,563 km 6 Australia – 66,530 km 7 Norway – 53,199 km 8 Philippines – 33,900 km 9 Brazil – 33,379 km 10 Finland – 31,119 km 11 China – 30,017 km 12 Japan – 29,020 km

  Amazingly, few animals died in the tsunami that hit Sri Lanka and other areas in 2004. Elephants, buffalo and tigers, as well as smaller animals, moved to high ground in time. Scientists think that they sensed sound waves and changes in air pressure in advance of the wave and this gave them time to escape .

  The word tsunami comes from the Japanese tsu (meaning port) and nami (meaning wave). A tsunami is not a tidal wave, but a powerful surge of moving water caused by an earthquake or volcanic eruption beneath the sea bed. There may be advance warning signs, such as bubbling water, a roaring noise and a sudden rise in water temperature. Tsunamis are rarely as high as tidal waves, However, powerful ones can cross huge distances, raising the sea level and destroying entire islands and coastal areas in their path. Lisbon , the capital of Portugal, was almost completely destroyed in 1755 by the combined effects of an earthquake, tsunami  and fire. The worst recorded tsunami occurred in 2004 in South East Asia.

  The Wave height scale describes the sort of waves that sailors might meet at sea. wave height varies according to wind speed. High waves can be very dangerous, especially to small boats which can be turned over and even smashed.   0 Glassy – 0.0m 1 Calm – 0.0-0.30 m 2 Rippled – 0.30-0.60 m 3 Choppy – 0.60-1.2 m 4 Very choppy – 1.2-2.4 m 5 Rough – 2.4-4.0 m 6 Very rough – 4.0-6.0 m 7 High – 6-9 m 8 Very High – 9.0-14 m 9 Ultra High – 14.0 m+