(CNN) Sunburned? You're not the only one.

According to data from the National Oceanic and Atmospheric Administration (NOAA), 2018 is on pace to be the fourth hottest year on record. Only three other years have been hotter: 2015, 2016 and 2017.

The upward trend is not lost on experts, who say the rising temperature is a clear indicator of global warming.

"The impacts of climate change are no longer subtle," said Michael Mann , a climate scientist and director of the Earth System Science Center at Penn State University.

"We are seeing them play out in real time in the form of unprecedented heat waves, floods, droughts and wildfires. And we've seen them all this summer," he said.

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