The US space agency has confirmed that July was the hottest month on record ever since 1880, as heatwaves and wildfires hit the cities in the US and Europe.

According to scientists at NASA's Goddard Institute for Space Studies (GISS) in New York, July 2023 was hotter than any other month in the global temperature record.

Overall, July 2023 was 0.24 degrees Celsius warmer than any other July in NASA's record, and it was 1.18 degrees Celsius warmer than the average July between 1951 and 1980.

High sea surface temperatures contributed to July's record warmth. NASA's analysis shows especially warm ocean temperatures in the eastern tropical Pacific, evidence of the El Nino that began developing in May 2023.

"NASA data confirms what billions around the world literally felt: temperatures in July 2023 made it the hottest month on record. In every corner of the country, Americans are right now experiencing firsthand the effects of the climate crisis, underscoring the urgency of President Biden's historic climate agenda," NASA Administrator Bill Nelson said in a statement late on Monday.

"The science is clear. We must act now to protect our communities and planet; it’s the only one we have."

Parts of South America, North Africa, North America, and the Antarctic Peninsula were especially hot, experiencing temperatures increases around 4 degrees Celsius above average.

Overall, extreme heat this summer put tens of millions of people under heat warnings and was linked to hundreds of heat-related illnesses and deaths.

The record-breaking July continues a long-term trend of human-driven warming driven primarily by greenhouse gas emissions that has become evident over the past four decades.

According to NASA data, the five hottest Julys since 1880 have all happened in the past five years.

"Climate change is impacting people and ecosystems around the world, and we expect many of these impacts to escalate with continued warming," said Katherine Calvin, chief scientist and senior climate advisor at NASA Headquarters in Washington, DC.

This July was not just warmer than any previous July -- it was the warmest month in our record, which goes back to 1880, added Goddard Institute for Space Studies (GISS) Director Gavin Schmidt.