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The Reasons Behind This Summer’s Intense Heat

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As the summer of 2023 unfolds, a global heatwave of unprecedented intensity has gripped the world, affecting millions of people and shattering decades-long temperature records. This phenomenon has sparked widespread concern and curiosity, leading to a pressing question: what causes this summer’s intense heat? This article aims to unravel the complex factors contributing to this extreme weather pattern, including climate models, oceanic influences, and greenhouse gas emissions. By understanding these elements, you can better comprehend the current situation and anticipate future climate trends.

The Heatwave In Numbers

The summer heatwave has manifested in staggering numbers, particularly in the United States and the United Kingdom. In the US, over a third of the population, equating to more than 113 million people, are under some form of heat advisory issued by the US National Weather Service. In El Paso, Texas, temperatures have soared above 37C for 27 consecutive days, breaking a record last set in 1994.

Across the Atlantic, the UK has not been spared from the scorching heat. The June heat didn’t just break records; it smashed them. The temperature was 0.9C hotter than the previous record, which was set back in 1940. This significant increase in temperature is a clear indication of the severity of the current heat wave.

Global Impact Of The Heatwave

The heatwave’s impact extends far beyond the US and UK, with North Africa, the Middle East, and Asia also experiencing unprecedented hot weather. The European Centre for Medium-Range Weather Forecasts has stated that June was the hottest on record globally, underscoring the widespread nature of this heatwave.

According to the EU Climate and weather service, Copernicus, the three hottest days occurred in the past week alone. The average world temperature hit 16.89C on July 3 and topped 17C for the first time on July 4. These figures highlight the global scale and intensity of the heatwave.

The Role of Climate Models

Climate models have played a crucial role in predicting these high temperatures. According to Prof Richard Betts, a climate scientist at the Met Office and the University of Exeter, these highs align with climate models’ predictions. These models consider various factors, including greenhouse gas concentrations, to project future climate conditions.

Betts further explains that we should not be surprised by the high global temperatures. “This is all a stark reminder of what we’ve known for a long time, and we will see ever more extremes until we stop building up more greenhouse gases in the atmosphere,” he says. This statement underscores the critical role of human-induced climate change in driving these extreme temperatures.

The Ocean’s Influence

The oceans significantly influence global temperatures, and this year, record ocean temperatures have been observed. The North Atlantic, for example, is currently experiencing the highest surface water temperatures ever recorded. This marine heatwave has been particularly pronounced around the coasts of the UK, where some areas have experienced temperatures as much as 5C above what you would normally expect for this time of year.

Simultaneously, El Niño is developing in the tropical Pacific. El Niño is a recurring weather pattern caused when warm waters rise to the surface off the coast of South America and spread across the ocean. With both the Atlantic and the Pacific experiencing heatwaves, it is perhaps not surprising that global sea surface temperatures for April and May were the highest ever recorded.

The Greenhouse Gas Factor

The continuous increase in greenhouse gas emissions significantly contributes to the heat wave. These emissions continue to increase yearly, and the higher the global temperature, the higher the risk of heat waves. The growth rate has slowed slightly, but energy-related CO2 emissions were still up almost 1% last year, according to the International Energy Agency, a global energy watchdog.

Friederike Otto, a climatologist at the Grantham Institute of Climate Change at Imperial College London, explains, “These heatwaves are not only more frequent but also hotter and longer than they would have been without global warming.” This statement underscores the direct link between greenhouse gas emissions and the increasing severity of heat waves.

The Future Predictions

Experts predict that the developing El Niño will likely make 2023 the hottest year. They fear it will temporarily push the world past a key 1.5C warming milestone. This prediction is based on the understanding that El Niño events often lead to global temperature spikes.

This is just the start. Unless we dramatically reduce greenhouse gas emissions, temperatures will continue to rise. The Met Office said this week that record June temperatures this year were made twice as likely because of man-made climate change.

The Environmental Impact


The rising temperatures are already driving fundamental and almost certainly irreversible changes in ecosystems worldwide. For example, the record June temperatures in the UK helped cause unprecedented fish deaths in rivers and canals. These incidents highlight the immediate and devastating impact of the heatwave on wildlife.

The current marine heatwave’s impact on the UK is still unknown, but Prof Schmidt of the University of Bristol cautions that we have never seen one this intense. “In other regions, around Australia, in the Mediterranean, entire ecosystems changed, kelp forests disappeared, and seabirds and whales starved,” she says. This statement underscores the potential for widespread ecological disruption due to the heat wave.

The Bottom Line

The summer of 2023 has been marked by an intense global heatwave, the causes of which are multifaceted and complex. From the role of climate models and oceanic influences to the impact of greenhouse gas emissions, these factors intertwine to create a climate scenario of unprecedented heat. As we move forward, it is clear that we can expect more extreme weather patterns unless we make significant strides in reducing greenhouse gas emissions. The question now is whether we can act swiftly and decisively enough to slow the climate juggernaut and keep the impacts of global warming within manageable boundaries.