Record-Breaking Global Heat: Uncovering the Factors Behind Unprecedented High Temperatures
The world is currently experiencing an unprecedented heatwave, with record temperatures being shattered by significant margins. Experts are delving into the contributing factors to understand why the world is heating up at such an alarming rate and what implications this has for our commitment to the Paris Agreement.
One key factor is the occurrence of a significant El Nino, which is still intensifying. During an El Nino event, the surface ocean in the tropical Pacific experiences a warming effect. This, along with the impact of El Nino in other parts of the world, contributes to a rise in global average temperatures by approximately 0.1 to 0.2°C.
Considering that we have recently transitioned from a triple La Nina, which slightly cools global temperatures, and that this is the first major El Nino in eight years, it’s not surprising to witness abnormally high temperatures at the moment. However, El Nino alone does not account for the extremely high temperatures we are observing.
Human-generated air pollution has a cooling effect on the planet and helps offset some of the warming caused by greenhouse gas emissions. Efforts have been made to reduce pollution levels, such as the international agreement in 2020 to reduce sulphur dioxide emissions from the global shipping industry.
It has been suggested that cleaner air resulting from reduced pollution may be contributing to the recent heat, particularly in regions with high shipping traffic such as the record-warm north Atlantic and Pacific areas. However, this effect is estimated to contribute only a fraction of a degree to the overall temperature increase by 2050.
While decreasing pollution levels allow more of the Sun’s energy to reach the Earth’s surface, it’s important to note that solar activity itself varies. The most relevant solar cycle, which follows an 11-year pattern, is currently experiencing increased activity since its minimum in late 2019. This, too, contributes only a small fraction of a degree to recent global warming.
Back in January 2022, the underwater Hunga Tonga-Hunga Ha’apai volcano erupted in the South Pacific Ocean, releasing a significant amount of water vapor into the upper atmosphere. Water vapor acts as a greenhouse gas, intensifying the greenhouse effect when its concentration rises in this manner.
Despite the eruption occurring almost two years ago, it continues to have a minor warming effect on the planet. However, like the reduced pollution and increasing solar activity, we’re talking about a negligible rise in temperature.
Even without factors like El Nino, pollution changes, or solar activity, global temperatures naturally exhibit variability from one year to the next. The extreme heat observed in September 2023 can be attributed, in part, to the positioning of weather systems that warm the land surface.
When high-pressure systems persist over land regions, as seen recently in western Europe and Australia, local temperatures rise, creating conditions for unseasonably high heat. However, the response in ocean temperatures is relatively slower due to the higher energy required to warm water and its mobility.
The combined effect of weather systems warming land areas and persistently warm oceans likely contributes to the overall global heat. Nevertheless, the overwhelming contributor to the +1.7°C global temperature anomaly is human-caused climate change. Over time, humanity’s impact on the climate has led to a global warming of approximately 1.2°C.
The record-breaking pace of greenhouse gas emissions points to an acceleration of global warming. While these emissions explain the long-term trend seen in September temperatures over many decades, they do not fully account for the significant difference between last September and September 2023. Factors such as the shift from La Nina to El Nino and specific weather patterns contribute to this disparity.
The key takeaway from September 2023 is that a combination of climate change and various factors aligning can result in alarmingly high temperatures. While these anomalies may surpass the 1.5°C global warming threshold mentioned in the Paris Agreement, it’s important to remember that the agreement aims to limit long-term global warming and not individual months of extreme heat.
Nonetheless, the effects of climate change are becoming increasingly evident and impactful. The most vulnerable populations bear the brunt of these consequences, while wealthier nations, responsible for the largest proportion of greenhouse gas emissions, continue to display slower progress in emission reduction. To prevent further record-breaking global temperatures and mitigate the impacts of extreme events, humanity must accelerate its path to achieving net-zero emissions.
In conclusion, the record-breaking global heat witnessed today is driven by a combination of factors, with climate change standing as the primary culprit. Understanding the key influences contributing to rising temperatures is crucial for formulating effective strategies to combat and adapt to this pressing issue. With the urgency of the situation at hand, it is imperative that we take swift action to address climate change and its repercussions on our planet.
