In a recent study, last year's extreme heat in the northern hemisphere, which caused wildfires to spread across the Mediterranean, buckling roadways in Texas, and straining power grids in China, not only made it the warmest summer on record but also the warmest in around 2,000 years, according to Reuters.

The startling finding is based on one of two new studies made public on Tuesday, as global temperatures and greenhouse gas emissions are rising.

Scientists officially proclaimed the period from June to August of last year as the warmest since record-keeping started in the 1940s.

A recent study published in the journal Nature reveals that the heatwave of 2023 may have exceeded temperatures over a much longer period. The study looked at temperature data derived from the investigation of tree rings at nine northern sites as well as meteorological records that go back to the middle of the 1800s.

Climate scientist Jan Esper of Johannes Gutenberg University in Germany, who co-authored the paper, said, "When you look at the long sweep of history, you can see just how dramatic recent global warming is."

According to the study, summertime temperatures in areas between 30 and 90 degrees north latitude last year were 2.07 degrees Celsius (3.73 degrees Fahrenheit) higher than pre-industrial averages.

The summer months of 2023 were, on average, 2.2 C (4 F) higher than the predicted average temperature for the years 1 to 1890, according to tree ring data.

The result did not come as a complete surprise. By January, researchers with the Copernicus Climate Change Service of the European Union concluded that 2023 was "very likely" to have been the warmest year in around a million years.

Esper stated it is improbable that such a lengthy record can be proven. In an article published last year, he and two other European scientists stated that the present scientific methods—which include extracting temperature data from sources like sea sediments or peat bogs—could not make year-by-year comparisons over such a massive time scale.

"We don't have such data," Esper said. "That was an overstatement."

El Nino climatic patterns, which usually correspond with warmer global temperatures, intensified last year's intense summer heat and resulted in "longer and more severe heatwaves, and extended periods of drought," according to Esper.

More than 150,000 deaths in 43 countries were connected to heatwaves annually between 1990 and 2019, according to the findings of a second study that was published on Tuesday in the journal PLOS Medicine. Heatwaves are already hurting people's health.

That would be equivalent to 1% of all deaths worldwide, or nearly the same number as the COVID-19 pandemic.

Over 50% of the additional deaths attributed to heatwaves happened in densely populated Asia.

With an average of 655 heat-related deaths annually per 10 million inhabitants, Europe had the highest per capita toll when the data were adjusted for population size. Greece, Malta, and Italy had the highest excess fatalities in the region.

Severe heat can induce heat stroke, breathing difficulties, and heart problems.