El Niño & Global Temperature 2023-2024

Greenhouse gas pollution and a strong El Niño have pushed the average global temperature to record highs this year. In June, the global temperature briefly spiked to 1.5°C above the average of the pre-industrial era. In July, the world experienced its hottest month on record, and the average temperature for the entire month was around 1.5°C above the pre-industrial average. This year’s August, September, and October beat the temperature records for each of those months, and now, 2023 is “almost certain” to be the hottest year on record. As El Niño deepens and releases even more heat from the ocean this year, it will push us to new extremes that underscore the importance of limiting global warming (of the atmosphere) to a long-term average of 1.5°C, at which point the impacts of warming are likely to become rapidly more severe. At our current rate of warming, we are on track to hit long-term average global warming of 1.5°C – the threshold established by the Paris Climate Agreement – in just 7 to 12 years.

El Niño turns up the heat

El Niño, the warm phase of the climate pattern known as the El Niño Southern Oscillation (ENSO), alters weather patterns worldwide by releasing tremendous amounts of heat from the ocean up into the atmosphere. El Niño conditions began in May and reached “moderate” severity by the end of June, with tropical Pacific temperatures 1°C above average. As of mid-Oct 2023, El Niño conditions in the central-eastern equatorial Pacific have plateaued at the level of a moderate El Niño event, with sea surface temperatures 1.5°C above average.

The double whammy of El Niño and human-caused climate change make it likely that 2023 will beat the annual global atmospheric temperature record set in 2016, which was 1.1°C above the pre-industrial average, according to the World Meteorological Organization (WMO). That year, an intense El Niño triggered deadly heat and precipitation and was linked to rainforest losses, coral bleaching and a rise in diseases such as cholera and dengue. This year’s El Niño could lead to global economic losses of $3 trillion, shrinking economic activity as extreme weather decimates agricultural production, manufacturing, and helps spread disease.

We can expect more extreme El Niños due to climate change

Global warming is reshaping the evolution and intensity of El Niño events in a way that favors the occurrence of more “super” El Niños like the ones that occurred in 1982/83, 1997/98, and 2015/16. These extreme El Niños feature very high temperatures in the central Pacific and reverberate all over the planet with major droughts, floods, heatwaves, and storms. Historically, big El Niños come along every 10 to 15 years, but now, scientists are warning of a potential "super El Niño” in 2023-24. It would be “very unusual” to see a super El Niño so soon after the last one in 2015-2016.

Short-term fluctuations versus long-term warming

While the average global air temperature has risen to 1.5°C above the pre-industrial average during 2023, long-term warming is still well short of the 1.5°C limit adopted by the Paris Climate Agreement. The Agreement looks at a sustained rise in global temperature of 1.5°C across multiple decades, a rise driven by carbon pollution, not short-term fluctuations. Importantly, the warning offered by the IPCC detailing the impacts of warming at 1.5°C is based on a 20-year sustained rise in global temperature, not a spike for a couple of weeks, not even a spike for a couple of years. However, these spikes will become increasingly common as we approach that long-term average.

The WMO now expects each year between 2023 and 2027 to meet or exceed the global average temperature record of 2016, reaching 1.1°C to 1.8°C above average. But it will take many years at or above 1.5°C for the 20-year global surface temperature average to cross the important threshold of 1.5°C. The 1.5°C number stems from the 2015 United Nations Paris agreement on climate change and was chosen in an attempt to limit the severity of the impacts of warming, taking into account factors such as food security and extreme weather events. According to the most recent climate change report by the IPCC, “the central estimate of 20-year averaged global surface warming crossing the 1.5°C level lies in the early 2030s.”