Human-induced climate change has been at the center of debate for decades, but according to the results of a research project, global warming is not a new problem. An international team of 25 climate scientists found human activity has been at the root of global warming since the early stages of the Industrial Revolution.

For the study, published in the journal Nature, researchers from Australia, the United States, Europe, and Asia worked together to sort through the Earth’s history over the past 500 years in order to pinpoint the exact time humans began contributing to rising greenhouse gas levels. Scientists analyzed climate records from the world’s oceans and continents, including corals, water levels, caves, tree rings, and ice cores, and found it was roughly the 1830s when an abnormal spike in greenhouse gases emerged on the planet. There was no other explanation except for the sudden increase in pollution from industry.

"The early onset of warming detected in this study indicates the Earth's climate did respond in a rapid and measureable way to even the small increase in carbon emissions during the start of the Industrial Age," said the study’s co-author Dr. Helen McGregor, climate change researcher from Australia’s University of Wollongong’s School of Earth and Environmental Sciences, in a statement.

Previously, researchers believed global warming was born in the 20th century because there weren’t enough records before the 1900s to make an exact estimate of when the phenomenon first began. The team also studied major volcanic eruptions from the early 1800s, but found they contributed little to the first signs of climate change.

"It was an extraordinary finding," said the study’s lead researcher Nerilie Abram, a professor from Australian National University’s Research School of Earth Science, in a statement. "It was one of those moments where science really surprised us. But the results were clear. The climate warming we are witnessing today started about 180 years ago."

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Source: Abram N, McGregor H, and Tierney JE, et al. Early onset of industrial-era warming across the oceans and continents. Nature. 2016.