The northern hemisphere experienced the hottest spring on record, data released by NASA has shown.
The latest data shows that global temperature records were broken in May 2016.
The high temperatures led to the 'very early onset' of the annual melting of ice in Greenland and the Arctic sea.
A number of extreme weather events also took place during May, including the exceptionally high rainfall in France.
In Australia, the hottest autumn on record has helped contribute to "unprecedented bleaching of the Great Barrier Reef."
The World Meteorological Organisation says the strong El Niño weather event in the Pacific helped fuel the high temperatures.
However, the organisation stresses that the 'underlying cause of global warming remains greenhouse gases in the atmosphere due to human activities.'
David Carlson, Director of the World Climate Research Programme, said: “The state of the climate so far this year gives us much cause for alarm. Exceptionally high temperatures. Ice melt rates in March and May that we don’t normally see until July. Once-in-a-generation rainfall events.
"The super El Niño is only partly to blame. Abnormal is the new normal," he added.
Earlier this week, researchers released findings showing that this year's El Niño contributed to atmospheric concentration of carbon dioxide reaching a 'symbolic threshold':