Summer of 2023 was the hottest in 2,000 years in the northern hemisphere, says study

The intense northern hemisphere summer heat that caused fires in the Mediterranean, closed roads in Texas and disrupted power grids in China last year made it not only the hottest summer on record – but the hottest in about 2,000 years. , points out new research.

The discovery comes from one of two new studies released this Tuesday (14).

Scientists quickly declared the period from June to August last year as the hottest since records began in the 1940s.

The new document published in the journal Nature suggests that the heat of 2023 will collapse temperatures and break historical records, when comparing meteorological records from the mid-1800s.

“When you look at history, you can see how dramatic global warming is,” said study co-author Jan Esper, a climate scientist at Johannes Gutenberg University in Germany.

Last year's summer season temperatures in the Northern Hemisphere were 2.07°C warmer than pre-industrial averages, the study said.

Based on tree ring data, the summer months in 2023 were, on average, 2.2°C warmer than the estimated average temperature over the years 1 to 1890.

The discovery, however, was not a surprise. In January, scientists from the European Union's Copernicus Climate Change Service said the year 2023 was “very likely” to be the hottest in around 100,000 years.

However, proving such a long record is very difficult, Esper said. He and two other European scientists argued in a paper last year that year-to-year comparisons could not be made on such a vast time scale with current scientific methods.

“We don’t have that data,” Esper said. “That was an exaggeration.”

Last year's intense summer heat was amplified by the El Nino weather pattern, which typically coincides with warmer global temperatures, generating “longer, more severe heat waves and extended periods of drought,” Esper said.

Heat waves are already affecting people's health. More than 150,000 deaths in 43 countries linked to heat waves were recorded between 1990 and 2019, according to details of a second study published this Tuesday (14), in the journal PLOS Medicine.

This represents around 1% of global deaths – approximately the same number of victims of the Covid-19 pandemic.

More than half of these heatwave-related deaths occurred in Asia.

When the data is adjusted for population size, Europe had the highest number per capita, with an average of 655 heat-related deaths per year per 10 million inhabitants. In the region of Greece, Malta and Italy the highest number of deaths were recorded.

Extreme heat can trigger heart problems and difficulty breathing.