May 2024 is the twelfth month in a row to break heat records

Another month, another record, as Earth’s unprecedented run of record-breaking heat continues. Global temperatures last month were the highest ever recorded for the month of May, making this the 12th month in a row to set a record of this kind, according to the European Union’s Copernicus Climate Change Service.

While this current sequence will come to an end at some point, the records set in the past year will be exceeded in coming years as the world continues to warm due to rising greenhouse gas levels, Carlo Buontempo at Copernicus said in a statement. “This string of hottest months will be remembered as comparatively cold,” said Buontempo.

The average air temperature across Earth’s surface during May 2024 was 1.52°C above the 1850 to 1900 average, regarded as the preindustrial level, and 0.19°C above the previous warmest May, in 2020. May 2024 is the 11th consecutive month with an average temperature more than 1.5°C above preindustrial levels, a threshold countries aim to avoid surpassing under the 2015 Paris Agreement.

The global average temperature over the past 12 months is the highest on record, at 1.63°C above the 1850 to 1900 average. However, climate scientists won’t regard the 1.5°C limit as being breached until the long-term average exceeds this level.

Climate scientists expected 2023 and 2024 to be hot because of the emergence of the El Niño phenomenon in the Pacific, which releases ocean heat into the atmosphere and temporarily boosts surface warming in addition to the trend due to rising greenhouse gases. In the event, temperatures have been even higher than forecast, for reasons that remain unclear.

El Niño is now giving way to La Niña, during which large parts of the Pacific Ocean absorb more heat from the atmosphere than usual. This can cause surface temperatures to fall temporarily. But with sea surface temperatures still at record levels, 2024 is still looking likely to be even hotter than 2023.

The abnormal warmth in May led to extreme heat and heatwaves in regions around the world. A heatwave has been affecting large parts of India, for instance, with temperatures in the capital Delhi reaching a new record of 49.9°C (121.8°F) on 28 May.

In Mexico, howler monkeys have been dropping dead from trees during a prolonged heatwave. This heat is now extending northwards into the US.

Last year, a study warned that as the world passes the 1.5°C limit, heatwaves could become so extreme that they cause mass deaths in places where people aren’t used to such heat and buildings aren’t designed for it.