Nov 7, 2023 - Energy & Environment

Earth has warmest October on record, new data shows

October global surface temperature anomalies
Data: JRA-55 via Zeke Hausfather; Chart: Simran Parwani/Axios

Last month may not have been as "gobsmackingly" hot as September, but the globe set a decisive record for its warmest October on record.

Driving the news: The findings, from European and Japanese research center data, come from computer model re-analyses. That involves cobbling together data from buoys, surface weather stations, satellites and other sources in near-real-time.

Why it matters: Earth is well on its way to having its warmest year on record, peppered with deadly extreme weather events. Many of these would have been less severe if there were fewer excess greenhouse gases from human activities.

Zoom in: For example, Hurricane Otis' explosive rate of intensification, going from a tropical storm to Category 5 hurricane in just one day, has been tied in part to warming ocean waters due to climate change.

By the numbers: Based on data from the Japan Meteorological Agency, October had a monthly temperature departure of 0.95°C (1.71°F) from the 1981-2010 average.

  • There is an ongoing El Niño event in the tropical Pacific Ocean, which helps to increase global average temperatures temporarily, but climate scientists say it cannot account for each of the shattered records this year.

What they're saying: "While not quite as bananas as September, it remains gobsmackingly warm," climate scientist Zeke Hausfather told Axios via email.

  • "It was the second highest monthly temperature anomaly (e.g. departure from normal) that we've seen all year after September 2023," Hausfather said.
  • He said it is "increasingly likely" that some data sets will show that 2023 was the first individual year to have an annual average temperature above 1.5°C compared to preindustrial levels.
  • This is significant, since the most ambitious target of the Paris Climate Agreement calls for limiting warming to 1.5°C above the preindustrial era in order to minimize the harmful effects from climate change.

Yes, but: That target, which we're currently on course to miss on the high end, refers to long-term warming, not an individual year.

What's next: Expect other climate milestones to be announced throughout the month as international scientific institutions weigh in with their numbers, released in the run-up to the COP28 climate summit in Dubai, which starts Nov. 30.

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