(CN) – Scientists discovered that global warming has increased at an unparalleled rate in the past 150 years, compared to the past 2,000 years, according to a new study released Wednesday.
The study, published in the journal Nature, found evidence that refutes climate change deniers’ claims that current global warming is part of a natural cycle of global climate events.
Events such as the Little Ice Age and Medieval Warm Period are often cited as examples of natural global climate changes by those who deny that modern global warming is human-caused. Raphael Neukom, study co-author from the University of Bern, said in the study that while such changes did occur, they did not happen on a global scale as is seen currently.
“It’s true that during the Little Ice Age it was generally colder across the whole world,” Neukom said, “but not everywhere at the same time. The peak periods of pre-industrial warm and cold periods occurred at different times in different places.”
Scientists in the study researched from an international database of climate data going back the last 2,000 years.
“The minimum and maximum temperatures were different in different areas,” Neukom said.
The authors said that the theory of global climate change cycles came only from the climate history of North America and Europe rather than the entire world. The study found no evidence of “globally coherent warm and cold periods” prior to the Industrial Revolution.
Instead, scientists found that “peak warming and cooling events” over the past 2,000 years were localized, compared to the past 150 years when global warming skyrocketed.
The researchers said evidence shows globally averaged temperatures in the past two millennia were marginally affected by “regionally specific mechanisms” such as volcanic activity. Those events are distinctive from the Earth’s current situation where warming has occurred globally rather localized to specific areas.
“The warmest period of the past two millennia occurred during the twentieth century for more than 98 percent of the globe,” the study states.