A draft of a federal climate change assessment yet to be approved by the Trump administration has found the average temperature in the United States has risen exponentially since 1980, according to a report.

The study by scientists from 13 federal agencies also revealed recent decades have been the warmest of the past 1,500 years, the New York Times reported.

"How much more the climate will change depends on future emissions and the sensitivity of the climate system to those emissions," the unpublished document states, before concluding Americans are already feeling the effects of climate change.

Among the study's other major findings is that some extreme weather can be attributed to climate change.

The report was compiled as part of the National Climate Assessment, which is congressionally mandated to be conducted every four years. It has been approved by the National Academy of Sciences, but still requires permission from the Trump administration before it can be officially released.

The New York Times initially reported that the study was leaked out of fear it would be suppressed by the administration. The Times later posted a correction on the story saying the report had appeared online in January, and was not leaked first to the newspaper.

Trump has said that he believes climate change could be a hoax perpetuated by the Chinese government and his administration has deprioritized research into extreme weather. Many scientists believe climate change and the subsequent warming of the globe are connected to human factors like the burning of fossil fuels.

Editor's note: The headline on this story has been changed after the New York Times' correction that the climate report had previously been published.