Humans have pushed global temperatures to historical highs this year, with 2015 set to be the warmest on record thanks to climate change, according to the United Nations.

The World Meteorological Organization (WMO), a branch of the United Nations (UN), said climate change had broken "symbolic thresholds," with global surface temperatures set to breach a 1 degree Celsius rise from pre-industrial levels - those counted between 1880 to 1899- by year-end.

It's been a relatively rapid increase, as shown by the fact that temperatures are already up 0.73 degrees Celsius against the period from 1961 to 1990, the report out Wednesday explained.

But that's not all: the three-month average for carbon dioxide (CO2) reached 400 parts per million for the first time, with greenhouse gas emissions breaking hitting another all-time high.

The WMO report comes less than a week before key climate change talks set to take place in Paris from November 30 to December 11. It's expected to deliver an agreement between over 190 countries that would aim to keep global temperatures from rising more than 2 degrees Celsius from pre-industrial levels.

"We have warmed the atmosphere by more than half of what we plan to do," Michel Jarraud, Secretary-General of the WMO, said during a press conference in Geneva on Wednesday.

"This is all bad news for the planet," Jerraud said.

Scientific evidence shows that extreme weather events like heatwaves and drought have increased by as much as 10 times as a result of human activities, the WMO report added.

For example, the heatwave that hit much of the US in 2012, causing power outages and a number of deaths, was one of the extreme weather events that was likely influenced by human-caused climate change, the report claimed.

Asia and South America have already recorded 2015 as their hottest year on record, with Europe and Africa marking it as their second hottest to date.

India saw some regions hit average temperatures of 45 degrees Celsius in May and June some areas, while further north, Poland saw all-time highs in Wroclaw in August at 38.9 degrees Celsius.

"The more we wait for action, the more challenging it will be, the faster we will have to reduce (our activities) afterwards, and probably the more expensive it will be ," Jarraud said.

"(But) it's still possible if there's a strong decision in Paris," he explained.

First Published:Nov 25, 2015 7:57 PM IST