Record-shattering heat: Summer of 2023 was earth's hottest in 2,000 years

Summer 2023 has set a scorching new record, marking the hottest season in the northern hemisphere in the past 2,000 years, according to a recent study. Comparing last year’s temperatures with historical climate data, researchers found that June, July, and August of 2023 were at least 0.5°C hotter than the most extreme past climates. This alarming trend was exacerbated by an El Nino weather pattern in the Pacific, which intensified the impact of human-caused global warming.

The study revealed that summer temperatures over northern hemisphere land in 2023 were 2.07°C higher than in the pre-industrial period (1850-1900), significantly exceeding the Paris Agreement’s target of limiting temperature increases to 1.5°C. 

A foreseeable crisis

The findings, published in the journal Nature, highlight that 2023 was the hottest year globally since records began in 1850. Human-caused climate change pushed northern summer highs beyond anything seen in two millennia.

“We shouldn’t be surprised,” stated Jan Esper, the study’s lead author and a professor of climatology at Germany’s Johannes Gutenberg University. “It’s the continuation of what we started by releasing greenhouse gases,” Esper told news agency AFP.

Using tree-ring data from sites across the northern hemisphere, scientists estimated global temperatures between the first century AD and 1850, before the advent of modern observational instruments. The conservative estimate found that 2023 was at least 0.5°C hotter than the warmest northern hemisphere summer of that period in AD 246, and potentially 1.19°C warmer.

Role of volcanic activity 

Study co-author Max Torbenson noted that 25 of the last 28 years exceeded the summer highs of AD 246, the hottest year before modern records began. By contrast, the coolest summer in that 2,000-year period was nearly four degrees cooler than the 2023 summer due to a major volcanic eruption. While volcanic activity could bring about cooler conditions in the future, the study emphasises that humanity’s release of greenhouse gases will continue to trap heat in the atmosphere.

In 1992, an eruption the previous year helped mitigate the impact of the El Nino weather system. However, once the effect subsided, temperatures soared in 1998, which the study noted as one of the warmest summers after 2023 and 2016, both also El Nino years.

Esper stressed that the only way to control temperature was to immediately start cutting emissions, “The longer we wait, the more difficult and expensive it will be," he said.

Health risks on the rise

Another study published on Tuesday warned that higher temperatures and ageing populations would expose tens of millions of older people to dangerous heat extremes by 2050. Currently, 14 per cent of elderly people are exposed to days exceeding 37.5°C, which can exacerbate health conditions and even lead to death. This figure is expected to rise to 23 per cent by mid-century, according to the study in Nature Communications.

The study’s lead author, Giacomo Falchetta, highlighted disparities in preparedness and adaptive capacity across different regions. Europe, although one of the fastest-warming areas, has systems to support people during heatwaves. In contrast, Africa and Asia, with rapidly growing elderly populations, lack sufficient access to clean water and healthcare to cope with extreme heat, Falchetta said.

“It raises questions of inequality around the world in terms of how governments and regions are equipped to cope with this,” he said.

Looking ahead

As climate change continues to be exacerbated by El Nino, temperature records are likely to be broken again in 2024. In recent weeks, exceptional heat waves have struck many Asian countries, with Myanmar experiencing its highest-ever April temperature of 48.2°C and parts of Delhi, India, recording temperatures as high as 50°C.

“When you look at the long sweep of history, you can see just how dramatic recent global warming is,” said Ulf Büntgen, a study co-author from the University of Cambridge. 

“2023 was an exceptionally hot year, and this trend will continue unless we dramatically reduce greenhouse gas emissions," he added.