Last year was the hottest on record, analyses by two major US agencies. Both Nasa and the National Oceanic and Atmospheric Administration said the global average temperature in 2014 was more than 1.2 degrees Fahrenheit above normal.

Scientists said the record temperatures were spread around the globe, including most of Europe stretching into northern Africa, the western United States, far eastern Russia into western Alaska, parts of interior South America, parts of eastern and western coastal Australia and elsewhere.

2014 hottest year
January 13, 2014: A teenager cools off on a water slide during a heat wave in Adelaide, Australia, where temperatures were expected to be over 40 degrees Celsius all weekDaniel Kalisz/Getty Images
2014 hottest year
January 23, 2014: A houseboat is removed from the receding water at Bridge Bay in Shasta Lake, which is 100 feet (30 metres) below its normal levels, in Shasta, CaliforniaRobert Galbraith/Reuters
2014 hottest year
January 27, 2014: An aerial view of small dams in dry paddocks north-west of the city of Melbourne. Australia endured its hottest year on record in 2013, with average temperatures 1.2 degree Celsius above the long-term average of 21.8 degree Celsius, breaking the previous record set in 2005David Gray/Reuters
2014 hottest year
January 29, 2014: The carcass of a cow is pictured in the town of Floresta, in Pernambuco State, during the hottest January on record in BrazilUeslei Marcelino/Reuters

With the exception of 1998, 10 of the warmest years on record have occurred since 2000.

Since 1880, when record-keeping began, Earth's average surface temperature has warmed by about 1.4 degrees Fahrenheit (0.8 degrees Celsius), a trend that is largely driven by the increase in carbon dioxide and other human emissions into the planet's atmosphere, Nasa said.

2014 hottest year
March 20, 2104: Tumbleweed surrounds a car in Fountain, Colorado, after prolonged drought and high winds created an explosion of tumbleweeds on the plains of southeastern Colorado, portions of New Mexico and the Texas panhandleRick Wilking/Reuters
2014 hottest year
April 16, 2014: Volunteers remove debris after deadly forest fires killed 15 people and destroyed at least 2,500 homes in Valparaiso, ChileEliseo Fernandez/Reuters
2014 hottest year
April 30, 2014: People evacuate from their homes as a wildfire driven by fierce Santa Ana winds closes in on them in Rancho Cucamonga in drought-parched Southern CaliforniaDavid McNew/Reuters
2014 hottest year
May 2, 2014: A lion is given a shower to cool down as temperatures rise at a zoological park in the Indian city of Jamshedpur, where officials predicted a high of 42 degrees CelsiusAFP

The global heat streak of the 21st century results in some mind-boggling statistics.

First, the NOAA calculates global average temperature going back to 1880. That's 135 years. So if no other forces were in play and temperatures last year were totally at random, then the odds of 2014 being the warmest on record are 1 in 135. Not too high.

But record and near record heat keep happening. The three hottest years on record – 2014, 2010 and 2005 – have occurred in the last 10 years. The odds of that happening randomly are 3,341 to one, calculated John Grego of the University of South Carolina.

Nine of the 10 hottest years on record have occurred in the 21st century. The odds of that being random are 650 million to one, statisticians said.

Thirteen of the 15 the hottest years on record have occurred in the last 15 years. The odds of that being random are more than 41 trillion to one.

All 15 years from 2000 on have been among the top 20 warmest years on record. The odds of that are 1.5 quadrillion to one. A quadrillion is a million billion.

And then there's the fact that the last 358 months in a row have been warmer than the 20th-century average, according to NOAA. The odds of that being random are incredibly high – a number with more than 100 zeroes behind it, Grego said.

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May 14, 2014: Firefighters spray water on a commercial structure consumed by the Poinsettia fire, one of nine wildfires fuelled by wind and record temperatures in San Diego County, CaliforniaDavid McNew/Getty Images
2014 hottest year
June 30, 2014: Small forest fires are pictured at night in the Sierra de Tejeda nature park near the town of Competa, near Malaga, southern SpainJon Nazca/Reuters
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July 16, 2014: A woman walks her dog in Bernal Heights Park, overlooking San Francisco, CaliforniaJustin Sullivan/Getty Images
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July 18, 2014: Two girls take a photograph of themselves as they relax in the sunshine in Hyde Park, London, as temperatures soared to their highest of the yearOli Scarff/Getty Images
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July 25, 2014: People cool off in a water park in Suining, southwest China's Sichuan province, as authorities issued a heatwave alertAFP
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July 30, 2014: A man walks across the dried-up bed of a reservoir in Sanyuan county, Shaanxi province. Droughts in most parts of China affected millions of hectares of agricultural cropsReuters
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July 31, 2014: A young man takes a break as Sydney enjoys a temperature of 22 degrees Celsius. Both Sydney and Melbourne experienced some of the hottest winter days on recordRenee McKay/Getty Images
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August 4, 2014: Home owners and emergency personnel prepare to evacuate a village threatened by the forest fire near Sala, Sweden. The fire, covering thousands of hectares, was classified as the worst forest fire in Sweden's modern historyFredrik Sandberg/TT News Agency/Reuters
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August 5, 2014: A boy sits on his father's shoulders as they cool down in a fountain in Tokyo where the temperature rose to 36 degrees CelsiusToru Hanai/Reuters
2014 hottest year
August 19, 2014: People try to lift a horse dying of hunger at the El Rosario farm in San Francisco Libre town in NicaraguaOswaldo Rivas/Reuters
2014 hottest year
September 4, 2014: An orangutan holds a paper bag over its head during a late summer heat wave at the National Zoo in Washington, DCKevin Lamarque/Reuters
2014 hottest year
September 12, 2014: Firefighters work to extinguish wildfires near the Sobradinho neighbourhood in Brasilia, triggered by prolonged drought, high temperatures and low humidityUeslei Marcelino/Reuters
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September 16, 2014: Firefighters battling the King Fire watch as a backfire burns along Highway 50 in Fresh Pond, CaliforniaNoah Berger/Reuters
2014 hottest year
November 18, 2014: An aerial view of the Atibainha dam, part of the Cantareira reservoir in Nazare Paulista, Sao Paulo state. Brazil's worst drought in 80 years has left the Cantareira system, that provides greater Sao Paulo with most of its water, with the lowest water level on record, with daily rationing becoming commonNacho Doce/Reuters