As France, India, the U.S., and other nations face unprecedented and deadly heat waves, new research published Wednesday showed the planet has warmed more quickly in recent decades than at any point in the past 2,000 years.

The new research, published in the journals Nature and Nature Geoscience, draws upon historical data which demonstrates warming in the 20th century has been more rapid and widespread than in the past, refuting climate deniers’ common refrain that current warming is part of a natural cycle.

As the BBC reported, the research team “reconstructed the climate conditions that existed over the past 2,000 years using 700 proxy records of temperature changes, including tree rings, corals and lake sediments” and “determined that none of these climate events occurred on a global scale.”

By contrast, the new research (pdf) states, “the warmest period of the past two millennia occurred during the twentieth century for more than 98 percent of the globe.”

“This provides strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures,” said the scientists, “but also unprecedented in spatial consistency within the context of the past 2,000 years.”