A new study has found that humans have triggered the last 16 record-breaking hot years experienced on Earth (up to 2014), with their impact on the global climate going as far back as 1937.
The study suggested that without human-induced climate change, recent hot summers and years would not have occurred.
The researchers also found that this effect has been masked until recently in many areas of the world by the wide use of industrial aerosols, which have a cooling effect on temperatures.
Researcher Andrew King said that everywhere they look, the climate change signal for extreme heat events is becoming stronger and the recent record-breaking hot years globally were so much outside natural variability that they were almost impossible without global warming.
The researchers examined weather events that exceeded the range of natural variability and used climate modelling to compare those events to a world without human-induced greenhouse gases.
The study is published in the journal Geophysical Research Letters.