Right after Pope Francis released his much-awaited encyclical calling for international action to curb global warming, the United States' National Oceanic and Atmospheric Administration (NOAA) released data showing that last month was the hottest May ever recorded in history.

The American agency reported that global average temperature last month reached a scorching 60.17 degrees Fahrenheit.

"The globally averaged temperature over land and ocean surfaces for May 2015 was the highest for the month of May since record-keeping began in 1880," the agency said.

This figure was higher by 0.14 degrees Fahrenheit compared to the temperature in May last year.

The temperature last month also exceeded the average worldwide temperature of 58.6 degrees Fahrenheit.

NOAA administrator Kathryn Sullivan said the new May data on temperature clearly shows that the Earth is getting warmer and warmer.

"The atmosphere is very, very clearly warming," Sullivan told Bloomberg.

To support this observation, the agency also released data showing that the high temperatures have also been recorded for the first four months of this year.

From March until May this year, global surface temperatures reached record-highs, measuring 1.53 degrees Fahrenheit above the 20th century average and 0.07 degrees Fahrenheit higher than previous high recorded in 2010.

Similarly, average temperatures from January to May also broke the earlier 2010 record by 0.16 degrees Fahrenheit, and the 20th century average by 1.53 degrees Fahrenheit.

With these figures, 2015 may well become the hottest year on record, exceeding already record-high temperatures recorded last year.

Global warming appears to be a clear manifestation of the Earth's ailing environment. In his encyclical released on Wednesday, Pope Francis said the Earth "is beginning to look more and more like an immense pile of filth."