Berkeley Earth revealed September 2023 was the warmest September ever measured globally in a report Wednesday.

According to the report, polar warming, global warming and an intensifying El Niño effect have contributed to the drastic increase in temperature.

New records are typically set when temperatures exceed standards by 0.1℃. However, September 2023 surpassed the 2020 record by 0.5℃. According to the report, these global temperature records have been directly measured since 1850.

Robert Rohde, author of the report and Berkeley Earth lead scientist, noted in the study that moderate Arctic and strong Antarctic polar warming is primarily responsible for the increase in global temperatures.

Although global warming is also a factor, it is a gradual process, raising Earth’s temperature by 0.19℃ per decade. In addition to polar warming, the sudden increase in warmth is more likely due to the El Niño effect in early June, the report notes. El Niño is expected to last until next year.

“The main reason for such spikes is internal variability in the distribution of heat and circulation of the oceans and atmosphere,” Rohde wrote in the report. “The largest and most well-known form of short-term internal variability is the El Niño / La Niña cycle originating in the Pacific. During the El Niño phase, global average temperatures tend to be slightly higher.”

September heat is not a new phenomenon in the bay. In early September last year, Berkeley faced a similar increase in temperature. David Romps, campus professor of climate physics in the department of earth and planetary science, pointed to global warming as the core cause.

“Heat waves have always happened, but global warming is making them worse and our continued reliance on fossil fuels puts us on track to make them much, much worse,” Romps said in a previous email to The Daily Californian.

Similarly, last week, Berkeley experienced an intense heat wave with temperatures rising into the 90s. According to Rob Mayeda, NBC Bay Area meteorologist, the cause of these warm days were high pressure and wind that created an “atmospheric hair dryer.”

Globally, Berkeley Earth estimates 77 countries also experienced their warmest September in 2023. According to the report, compared to the Earth’s local average from 1951 to 1980, almost 90% of the Earth’s surface was immensely warm.

Previous months have also set record-high monthly temperatures this year and, according to the data reported, 2023 is expected to be the warmest year on record.