July was the hottest month on Earth since U.S. temperature records began, scientists say

After extreme temperatures scorched vast sections of the planet in July, a worrying climate milestone anticipated by scientists has been corroborated by yet another prominent study. This time, it came from agencies in the U.S., where more than half of the population was subject to heat warnings at one point during the last month. 

On Monday, officials at NASA and the National Oceanic and Atmospheric Administration unveiled new data indicating that July was the hottest month on record, with both global sea-surface and land temperatures soaring well above longstanding averages. According to NOAA and NASA, Earth in 2023 saw its warmest July since temperature record-keeping began 174 years ago. 

Since July is climatologically the hottest month of the year, this year's numbers likely mean it was the hottest month on record overall, NOAA said in a news release. In a separate release issued Tuesday, NASA said scientists at its Goddard Institute for Space Studies in New York determined that "July 2023 was hotter than any other month in the global temperature record."

The data came on the heels of a similar report released earlier in August by the Copernicus Climate Change Service, a branch of the European Union's space program. That report also identified July 2023 as Earth's hottest month on record, noting that the global monthly temperature was unusually higher than average. July was so hot that officials at the United Nations announced it would likely break the planet's monthly record before July was even over. Later reports by the European climate agency and now by agencies in the U.S. have reinforced those suspicions.

Globally, the surface temperature on Earth in July was 2.02 degrees Fahrenheit greater than the 20th century's average temperature, which was 60.4 degrees Fahrenheit, data shows. It marked the first July in recorded history where the temperature exceeded 1.8 degrees above the long-term average, according to NOAA, which noted that the latest temperature record was also 0.36 degrees warmer than the previous July record, set in 2021. 

"July 2023 marked the 47th-consecutive July and the 533rd-consecutive month with temperatures at least nominally above the 20th-century average," the agency said.

This past July also marked the fourth consecutive month where global ocean surface temperatures reached a new record high, owing in part to the onset of El Niño, a recurring climate pattern determined by sea surface temperatures and precipitation levels across the equatorial Pacific. NOAA announced the arrival of El Niño, the "warm phase" of the climate cycle that replaces its counterpart, La Niña, in June. Also in June, the agency observed a record-high sea surface temperature, which was then topped by another anomaly seen in July — the latter measurement ultimately resulted in the highest monthly sea surface temperature anomaly in NOAA's 174-year record.

According to data collected by NASA, the five hottest Julys since the agency started tracking temperatures in 1880 have happened in the last five years. This year's record-breaking heat hit certain parts of the globe harder than others, with portions of South America, North Africa, North America and the Arctic Peninsula experiencing especially blistering weather. In those places, July temperatures in 2023 stood at about 7.2 degrees Fahrenheit above average, NASA said, attributing the phenomena mostly to the ongoing consequences of human-caused climate change.

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

In:
• National Oceanic and Atmospheric Administration
• Climate Change
• Heat Wave
• NASA