The following is a list of some of the worst natural calamities to strike the world since 1900. The list is by definition arguable. Earthquakes, volcanic eruptions, tsunamis, cyclones, hurricanes and other storms are all clearly natural phenomena.

But the picture is less clear for disasters like floods and famine. What some people may consider a natural disaster, others may consider more of a political act (for instance, some of the world's deadliest floods and famines were caused, at least in part, by policy decisions taken by hostile, indifferent or negligent regimes).

For our purposes, we have included floods and famines as well as flu pandemics on the assumption that disasters that are not man-made are, by definition, natural.

This list is also limited to disasters since 1900 — an arbitrary cut-off to be sure — but one made to reflect so-called "modern-day" disasters only.

The death tolls from disasters in the long-distant past are, at best, rough estimates. But there can be no doubt that our pre-1900 ancestors endured some appalling calamaties such as the bubonic plague ("The Black Death") that spread through Europe beginning in 1348 and wiped out an estimated one-third of humanity, or about 25 million people.

Earthquakes and tsunamis

Jan. 12, 2010. More than 230,000 people were killed when a 7.0-magnitude earthquake struck Haiti.

May 12, 2008. About 70,000 people were killed and 18,000 people were reported missing after a 7.9-magnitude earthquake struck Sichuan, China.

Oct. 8, 2005. At least 80,000 people were killed and three million left homeless after a quake struck the mountaineous Kashmir district in Pakistan.

Dec. 26, 2004. A magnitude 9.0 quake struck off the coast of Sumatra, triggering tsunamis that swept through the coastal regions of a dozen countries bordering the Indian Ocean. The death toll has been estimated at between 225,000 and 275,000.

Dec. 26, 2003. An earthquake devastated the ancient city of Bam, in central Iran, leaving between 31,000 and 43,000 people dead.

July 28, 1976. The 20th century's most devastating quake (magnitude 7.8) hit the sleeping city of Tangshan in northeast China. The official death toll was 242,000. Unofficial estimates put the number as high as 655,000.

Oct. 5, 1948 - More than 110,000 were killed when a 7.3 quake rolled through the area around Ashgebat in Turkmenistan.

May 22, 1927. A magnitude 7.9 quake near Xining, China, killed 200,000

Sept. 1, 1923. A third of Tokyo and most of Yokohama were levelled when a magnitude 8.3 earthquake shook Japan. About 143,000 were killed as fires ravaged much of Tokyo.

Dec. 16, 1920. China was also the site for the world's third-deadliest quake of the 20th century. An estimated 200,000 died when a magnitude 8.6 temblor hit Gansu, triggering massive landslides.

Dec. 28, 1908. Southern Italy was ravaged by a 7.2 magnitude quake that triggered a tsunami that hit the Messina-Reggio-Calabria area, killing 123,000.

Volcanic eruptions

July 15, 1991. Mt. Pinatubo on Luzon Island in the Philippines erupted, blanketing 750 square kilometres with volcanic ash. More than 800 died.

Nov. 13-14, 1985. At least 25,000 are killed near Armero, Colombia, when the Nevado del Ruiz volcano erupted, triggering mudslides.

May 8, 1902. Mt. Pelee erupted on the Caribbean island of Martinique, destroying the capital city of St. Pierre. Up to 40,000 were killed. The day before, a volcano had killed 1,600 people on the nearby island of St. Vincent and five months later Mt. Santa Maria erupted in Guatemala, killing another 6,000.

(Two of the most famous eruptions took place before 1900. In 1883, two-thirds of the Indonesian island of Krakatoa was destroyed when a volcano erupted. A resulting series of tsunamis killed more than 36,000. In 79 CE, Mt. Vesuvius erupted in southern Italy, destroying the ancient Roman city of Pompeii and two other communities. Thousands died.)

Hurricanes, cyclones and floods

July-August 2010. Floods triggered by heavier-than-normal monsoon rains hit northwest Pakistan. By the time the waters began to recede in late August, more than 160,000 square kilometres of land — about one-fifth of the country — was under water. More than 1,700 people were killed and 17.2 million people have been affected. 

May 3, 2008. Cyclone Nargis, swept along by winds that exceeded 190 kmh and waves six metres high struck the Burmese peninsula and may have left as many as 100,000 dead, according to U.S. estimates.

Oct. 26-Nov. 4, 1998. Hurricane Mitch was the deadliest hurricane to hit the Americas. It killed 11,000 in Honduras and Nicaragua and left 2.5 million homeless.

Aug. 5, 1975. At least 85,000 were killed along the Yangtze River in China when more than 60 dams failed following a series of storms, causing widespread flooding and famine. This disaster was kept secret by the Chinese government for 20 years.

August 1971. An estimated 100,000 died when heavy rains led to severe flooding around Hanoi in what was then North Vietnam.

Nov. 13, 1970. The Bhola cyclone in the Ganges delta killed an estimated 500,000 in Bangladesh. Some put the complete death toll as high as one million.

June, 1938. Nationalist Chinese soldiers, under the direction of Chiang Kai-Shek, blew up dikes around the Yellow River to stop Japanese troops from advancing. More than half a million people died in the resulting flood.

May-August 1931. Massive flooding of China's Yellow and Yangtze rivers led to almost four million deaths from drowning, disease and starvation. The flooding of the Yangtze also killed an estimated 100,000 in 1911 and 140,000 in 1935.

 Pandemics and famines

1900 to present. Malaria is one of the leading causes of death in the developing world even though it is curable and largely preventable. According to the World Health Organization, malaria causes severe illness in 500 million people each year and kills more than a million annually.

1984-1985. Famine killed at least one million in Ethiopia as severe drought led to desperate food shortages.

1980 to present. Toll from AIDS worldwide since 1980 is estimated at 25 million, with 40 million others infected with HIV.

1968. The Hong Kong flu became the third flu pandemic of the 20th century.

1965-67. Three years of drought in India resulted in an estimated 1.5 million deaths from starvation and disease. Severe Indian droughts also killed millions in 1900 and 1942.

1959-1961. The "Great Leap Famine" cost an estimated 20 to 40 million lives in China as the policies of Mao Zedong resulted in massive social and economic upheaval. China was also hit by large famines in 1907, 1928-1930, 1936 and 1941-1942.

1957-1958. The Asian flu swept around the world, killing an estimated two million and making it the second biggest flu pandemic of the century.

1932-1933. Failures in Soviet central planning and Stalin's decision to withhold food from the Ukraine led to huge loss of life. At least five million Ukrainians were among the seven million victims of that famine.

1921. A Soviet famine in 1921 began with a drought that caused massive crop failures. The initial death toll was greatly magnified when Lenin refused to acknowledge the famine and sent no aid. The Soviets later estimated that 5.1 million died.

1918-1919. An epidemic of "Spanish Flu" spread around the world. At least 20 million died, although some estimates put the final toll at 50 million. It's estimated that between 20 per cent and 40 per cent of the entire world's population became sick.

Sources: U.S. Geological Survey, World Health Organization, Associated Press,, NOAA, Guinness World Records, Oxfam.