Take the coldest year Minnesota ever had, 1883, and assign it a musical note — say, "D." Do that with the average annual temperature for every year since 1880 in the four northern regions of the globe and what you get in the end is — climate change for a string quartet.

Five University of Minnesota students are receiving national attention for that composition, especially Dan Crawford, a graduating senior who translated the global temperature data into music and put the project together.

Not surprisingly, the composition, "Planetary Bands, Warming World," starts low and ends up high, especially the violin that plays the music of the Arctic region, which is warming faster than the rest of the world. The average annual temperature for the 44th- through 64th-degree latitudes, which includes Minnesota, peaked at 36.1 degrees in 2007. As transcribed for the piece, it is two octaves higher than the corresponding 1883 temperature.

The string quartet is Crawford's second climate change composition. The first one, completed in 2013 at the suggestion of his science professor, also played across the world and was picked up by the Weather Channel and the Dot Earth blog in the New York Times. In that one, "A Song of Our Warming Planet," Crawford played notes representing the average annual surface temperature for the entire Earth, from 1880 on, a rare marriage of science and art.

But not a great piece of music. Crawford had to use almost every full and half-note in order to cover the entire range of temperature changes on his cello.

"It got the point across — it was really scary to listen to," he recalled in an interview. But musicians complained "that it wasn't very musical," he said.

So for "Planetary Bands, Warming World," he stayed in the major keys and took advantage of the range of four stringed instruments.

The result is a sad, sometimes discordant composition that ends as the violins fade away at the highest notes.

But it's an excellent teaching tool, said Scott St. George, Crawford's climatology professor, who came up with the idea in the first place.

He wanted a way to express climate change "without defaulting to some guy in front of a slide showing a graph," St. George said. "A lot of people don't think it's very interesting."

Hearing the world change

St. George and Crawford were shocked when the first piece swept around the world after it was posted on the website for the U's Institute on the Environment (IonE). Crawford was even interviewed on Skype for a Japanese television show.

"People were really interested in this new approach to the data," Crawford said.

The second composition tells an equally important but more complex story about the warming world. "That different regions of the globe are experiencing climate change differently," Crawford said.

Even St. George found it enlightening.

"I've learned things about the pattern of climate change that I don't think I would have realized just looking at a chart," he said. In 1941, for example, the note for the Arctic region leaps upward while the rest of the northern hemisphere was not unusually warm that year.

"I would not have noticed it if I hadn't heard the first violin take a jump up," he said. But then at other points in the composition the instruments move together, an indication that each region is warming at the same rate.

"You can hear that synchronicity," he said.

Crawford, who grew up in Madison, Wis., started out at the U thinking he would major in engineering. But after taking St. George's class as a freshman, he quickly changed his mind, and wound up with a double major in geography and environmental sciences, policy and management.

Eventually he wants to go to graduate school to study climate change, but for now he wants to find a job and save some money.

"And give my brain a break," he said.