The hottest month in the history of recorded global temperatures was July 2023, according to researchers at NASA’s Goddard Institute for Space Studies (GISS) in New York.
Overall, July 2023 was 1.18 degrees Celsius (1.43 degrees Fahrenheit) warmer than any previous July in NASA’s data and 0.43 degrees Fahrenheit (0.24 degrees Celsius) warmer than July between 1951 and 1980.
The primary focus of the GISS study is long-term temperature variations over many decades and centuries, and a set base period produces anomalies that are stable over time. Temperature “normals” are defined over a period of several decades, usually 30 years.
“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,” said NASA Administrator Bill Nelson.
An Analysis of the Temperature Records in July 2023
According to Copernicus, the European Union’s Earth Observation Program, the daily global mean surface air temperature record was broken four days in a row, from July 3-6.[1]
The 29 days from July 3 to July 31 were the warmest 29 days ever recorded, with every day breaking the previous record of 16.80°C set on August 13, 2016.
The temperatures recorded on July 5 and 7 came within 0.01 degrees Celsius of the highest day, July 6, when the global average temperature reached 17.08 degrees Celsius.
In addition, during the first and third weeks of the month, temperatures momentarily exceeded the 1.5°C limit set by the Paris Agreement above preindustrial levels.
Parts of South America, North Africa, North America, and the Antarctic Peninsula saw extreme heat, with temperatures rising by roughly 7.2 F (4 C) above normal.[2]
According to NASA data, the five hottest Julys since 1880 have all happened in the past five
Years.
The Need to Address the Heat Warnings
This summer’s excessive heat was responsible for hundreds of heat-related illnesses and deaths and placing tens of millions of people under heat advisories.
The breaking of records indicates that the long-term trend of human-caused warming, caused mainly by greenhouse gas emissions, has persisted through the month of July.
The warmest July on record was a result of elevated sea surface temperatures.
According to NASA’s analysis, the eastern tropical Pacific had particularly warm ocean temperatures, indicative of the El Nio that started to form in May 2023.
El Nio and La Nia, which warm and cool the tropical Pacific Ocean, account for a minor percentage of the year-to-year variance in global temperatures.
However, these contributions are usually insignificant when El Nio begins to form in the Northern Hemisphere in the summer.
El Nio will have the biggest impact in February, March, and April of 2024, according to NASA.
References
- Copernicus Climate Change Service, ‘July 2023 sees multiple global temperature records broken’, 31 July 2023, https://climate.copernicus.eu/july-2023-sees-multiple-global-temperature-records-broken[↩]
- NASA, ‘NASA Clocks July 2023 as Hottest Month on Record Ever Since 1880’, 14 August 2023, https://www.nasa.gov/press-release/nasa-clocks-july-2023-as-hottest-month-on-record-ever-since-1880/[↩]
