Gases such as carbon dioxide act as a barrier to heat escaping, and it becomes dispersed around the planet, slowly raising average temperatures.
While this also occurs through natural means, since the industrial revolution, the amount of carbon released into atmosphere has increased dramatically, adding an extra burden to the earth's fragile climate system.
Warmer temperatures result in melting ice caps, rising sea levels and more extreme weather conditions.
However, other factors affect the climate and scientists have also had to address a noticeable slowdown in the speed which the planet is warming up, despite the continued pumping of greenhouse gases.
The IPCC believes the reduction in recent years is down to variation in the climate system, along with volcanic eruptions putting cooling ash into the atmosphere and changes in the sun's strength.
Bill Collins, professor of climate change at the University of Reading and one of the authors of the report, said: "The climate hasn't stopped warming. We haven't seen it so much at the surface, but the heat has gone somewhere and it will come back."