Two warmest days on record occurred in July, warming in Antarctica may have played a role

The Earth witnessed two hottest days on record last month, with daily global average temperatures on July 22 and 23 registering 17.16 degrees Celsius (°C) and 17.15°C, according to the European Union’s Copernicus Climate Change Service.

Globally, the July 2024 surface air temperature of 16.91°C was 0.68°C above the 1991-2020 average for that month. It was also only 0.04°C lower than the previous high set in July 2023.

One factor that may have driven this spike in global temperature was the above-average temperatures over large parts of Antarctica reaching 10°C above average in some areas, and above-average temperatures in parts of the Southern Ocean, the World Meteorological Organization (WMO) pointed out.

“Although natural climate variability can play a role, such big temperature anomalies are unusual. It is the second such heat wave to hit the continent [Antarctica] in the last two years and a similar heat wave contributed to the record global temperatures in early July 2023,” WMO said.

The exceptionally warm temperatures across Antarctica are being driven by a strongly negative Southern Annular Mode (SAM) pattern, Simon Lee, Lecturer in Atmospheric Science in the School of Earth and Environmental Sciences at Scotland’s University of St Andrews, wrote on X.

SAM is the north-south movement of the strong westerly winds that blow almost continuously in the mid-to-high-latitudes of the Southern hemisphere. This is likely playing a role in short-term (daily-scale) global temperature fluctuations, the expert added.

The sea ice extent over the Antarctic was 11 per cent below average, the second-lowest figure for July in the satellite data record. In July 2023, the value was 15 per cent below average.

The Antarctic Peninsula, the part of Antarctica furthest from the South Pole, has been warming rapidly, five times faster than the global average. Since 1950, the Antarctic Peninsula has warmed almost 3°C (5.4°F). That's more warming than anywhere else in the Southern Hemisphere.

July records broken globally

Further, the mercury in July 2024 was 1.48°C above the estimated July average for the preindustrial period of 1850-1900. With this, the series of 12 consecutive months where temperatures either touched or crossed 1.5°C comes to an end.

Still, several parts of the world saw records being broken. “Widespread, intense and extended heat waves have hit every continent in the past year. At least 10 countries have recorded daily temperatures of more than 50°C in more than one location. This is becoming too hot to handle,” WMO Secretary-General Celeste Saulo stated. 

In Japan, the monthly average temperature in July was the highest in the instrumental record going back to 1898, with it being 2.16°C warmer than Japan’s July 1991-2020 average. China, too, experienced its warmest July on record. The warming trend continued in August, with maximum daily temperatures crossing 40°C in many places of eastern China, according to the China Meteorological Administration. Bahrain also saw its warmest July since 1902.

Repeated heat waves hit Pakistan and Iran. Morocco in North Africa experienced two consecutive heat waves with record temperatures. The second heat wave, which lasted from July 22-25, was particularly intense, reaching 41.7°C in Nouasseur and 47.6°C in Marrakesh.

In July, Death Valley in California saw a record average monthly temperature of 42.5°C. Las Vegas set a new record, with temperatures reaching 40.5°C or higher for 43 consecutive days.

In South America, parts of Bolivia, Paraguay, southern Brazil, Uruguay, and northern Argentina have seen the mercury crossing 30°C, and even above 35°C. The WMO noted that this is unusual for this time of the year, with anomalies up to 10°C being seen.

“Climate adaptation alone is not enough. We need to tackle the root cause and get serious about reducing record levels of greenhouse gas emissions,” Saulo said in a statement.