Summer of 2023 Breaks Heat Records, Becoming Hottest on Record, Says NASA

The summer of 2023 has set a new global temperature record, marking Earth’s hottest summer since 1880, as reported by scientists from NASA’s Goddard Institute of Space Studies (GISS) in New York.

The months of June, July, and August collectively registered a temperature 0.41 degrees Fahrenheit (0.23 degrees Celsius) higher than any previous summer in NASA’s records, and 2.1 degrees Fahrenheit (1.2 degrees Celsius) warmer than the average summer between 1951 and 1980. August alone recorded a temperature of 2.2 degrees Fahrenheit (1.2 degrees Celsius) above the average.

In the Northern Hemisphere, June through to August constitutes meteorological summer.

This new record coincides with widespread extreme heat events worldwide, contributing to devastating wildfires in Canada and Hawaii, severe heatwaves in South America, Japan, Europe, and the U.S., and potentially influencing heavy rainfall in Italy, Greece, and Central Europe.

“Summer 2023’s record-setting temperatures aren’t just a set of numbers – they result in dire real-world consequences. From sweltering temperatures in Arizona and across the country, to wildfires across Canada, and extreme flooding in Europe and Asia, extreme weather is threatening lives and livelihoods around the world,” remarked NASA Administrator Bill Nelson.

“The impacts of climate change are a threat to our planet and future generations, threats that NASA and the Biden-Harris Administration are tackling head on”, he said.

NASA compiles its temperature data, known as GISTEMP, using surface air temperature information collected from numerous meteorological stations worldwide, in addition to sea surface temperature data acquired from ships and buoys. Advanced methods are applied to account for variations in temperature station distribution and potential urban heat effects.

The analysis presents temperature anomalies rather than absolute temperature values, illustrating how much temperatures deviated from the 1951 to 1980 base average.

“Unusually, high sea surface temperatures, partly attributed to the return of El Niño, played a significant role in the summer’s record-breaking warmth,” explained Josh Willis, climate scientist and oceanographer at NASA’s Jet Propulsion Laboratory in Southern California.

El Niño is a natural climate phenomenon characterised by elevated sea surface temperatures (and higher sea levels) in the central and eastern tropical Pacific Ocean.

This record-setting summer of 2023 aligns with a long-term trend of warming.

Extensive scientific observations and analyses conducted over decades by NASA, the National Oceanic and Atmospheric Administration (NOAA), and other international organisations attribute this warming primarily to human-induced greenhouse gas emissions. Additionally, natural El Niño events in the Pacific often contribute to the warmest years on record, infusing extra warmth into the global atmosphere.

“We’re experiencing heatwaves that are longer, hotter, and more severe, with an atmosphere capable of holding increased moisture, making it harder for the human body to regulate temperature in hot and humid conditions,” noted Willis.

Scientists say the impacts of El Niño will become apparent in early 2024.

El Niño typically leads to weaker easterly trade winds and the westward movement of warm water from the western Pacific towards the western coast of the Americas. This phenomenon can result in widespread effects, including cooler and wetter conditions in the U.S. Southwest and drought in western Pacific countries such as Indonesia and Australia.

“Regrettably, climate change is a reality. What we forecasted is unfolding before our eyes,” said Gavin Schmidt, climate scientist and director of GISS. “And it will worsen if we continue emitting carbon dioxide and other greenhouse gases into our atmosphere.”

For comprehensive temperature data and a detailed description of the methodology used for temperature calculations and associated uncertainties, refer to NASA’s online resources.

GISS, affiliated with Columbia University’s Earth Institute and School of Engineering and Applied Science in New York, is a NASA laboratory managed by the Earth Sciences Division of the agency’s Goddard Space Flight Center in Greenbelt, Maryland.