July 2023 was the hottest month on record. While in many parts of the world temperatures were higher than average, other regions faced extreme heatwaves, highlighting the urgency of addressing climate change. However, according to The Conversation, global warming is not the only factor driving the rise in temperature.
Although the globe has already experienced extreme and intense weather events over the last few decades with global temperature rising gradually, the record-breaking high temperature documented this July has made many once again think of the issues of climate change. On average, the global temperature in July was 16.95ºC, approximately a third of a degree more than the previous record documented in 2019. While parts of Antarctica and South America faced higher than average temperatures, countries located in the northern hemisphere were hit by intense heatwaves. Samantha Burgess, Deputy Director of the EU’s Copernicus Climate Change Service, said that rising temperatures highlight the need for urgent efforts towards reducing greenhouse gases, noting that “2023 is currently the third warmest year to date at 0.43ºC above the recent average, with the average global temperature in July at 1.5°C above pre-industrial levels”.
Fig.1. Global averaged surface air temperature, all months of July 1940 – 2023. Blue indicates cooler than average years, red indicates warmer years.
Source: EuroNews
Commenting on the record-high temperature, the UN secretary general, António Guterres, said:
“The era of global boiling has arrived,” adding that “humanity is in the hot seat. For vast parts of North America, Asia, Africa and Europe, it is a cruel summer. For the entire planet, it is a disaster. And for scientists, it is unequivocal – humans are to blame”.
According to The Conversation, however, climate change only partially explains average global high-temperatures and heatwaves. Other factors, such as El Niño, solar fluctuations, and an immense underwater volcanic eruption, also lead to heatwaves, topping up the effects of global warming. For example, during El Niño, a phenomenon that occurs every few years, the direction of surface water in the tropical Pacific changes, warming up the atmosphere above which has a significant impact on global weather patterns. In 2016, when a strong El Niño occurred, the global average temperature increased by 0.14 C and, as a result, 2016 was the hottest year on record. Climate forecasting models reveal that, as the Pacific sea-surface temperatures increase in mid-2023, there is a 90% probability that the world will move toward another strong El Niño.
Fig.2. How global surface temperature changes with El Nino and La Nina.
Source: The Conversation
Apart from phenomena such as El Niño, solar fluctuation also plays a role in extreme weather events. While it may appear that the sun warms the planet in a stable way, in reality its energy output fluctuates slightly, reaching its warmest peak every 11 years. The solar maximum adds up to around 0.05C to the average solar output. At present, the solar cycle is expected to reach its peak in 2025, meaning that until then solar output will gradually increase every year.
Finally, substantial volcanic eruptions also impact weather patterns. In 2022, an enormous volcanic eruption of Tonga’s Hunga Tonga-Hunga Ha’apai occurred and is having a significant warming effect. According to studies, this may lead to the planet’s surface warming up by about 0.035C.
Overall, factors such as El Niño, solar fluctuations, and massive volcanic eruptions, together with the ongoing global warming, are expected to further raise the global temperature, putting pressure on humanity to address climate change.
