2010 was the year of the heatwave, with record temperatures set in 17 countries. Two leading groups of scientists say it was the warmest since records began in 1850; another suggests it was the second-warmest.
The most extreme temperature anomalies in 2010 occurred across most of Canada and Greenland, where annual temperatures were 3C or more above normal, and across much of Africa and south Asia, where annual temperatures were 1-3C above normal.
