According to the state of the climate report released by the World Meteorological Organisation (WMO) in Switzerland 2015 “shattered” temperature records.
A stronger-than-usual El Nino weather pattern pushed temperatures into uncharted territory all over the world, with climate change feeding the El Nino.
The dramatic temperature rise was foreshadowed by a preview report in November, but the final figures show an even higher leap than forecast.
The report is one of several from science agencies across the world that have been released in recent months describing the alarming extent of global warming.
In December last year world leaders met in Paris and agreed to a new treaty to limit the release of climate changing greenhouse gases and to keep global warming to “significantly less than 2.0°C”.
The document, known as the Paris Agreement, will be open for ratification at the United Nations in April.
“We are halfway to the critical 2.0°C threshold.
“National climate change plans adopted so far may not be enough to avoid a temperature rise of 3.0°C, but we can avert the worst-case scenarios with urgent and far-reaching measures to cut carbon dioxide emissions,” Mr Taalas said.
In 2015, the world was 0.76°C warmer than the late 20th Century and a whole degree warmer than the late 19th Century.
However the world does not warm evenly and South America and Asia had their hottest years on record, the United States, Africa and Europe had their second-warmest years.
Climate change and El Nino have a complicated relationship, with each feeding the other.
Last year, the El Nino weather pattern took hold, which usually pushes temperatures higher.
But the WMO said in 2015 climate change made the El Nino the strongest ever.
In addition to the high temperatures, the strong El Nino meant little rainfall for eastern and southern Australia.