Summer 2023 Is Recorded As The Hottest In The Last 2,000 Years In The Northern Hemisphere

Illustration of a hot summer. (photo: Doc. pexels)

JAKARTA - The latest analysis from the University of Cambridge shows that the summer of 2023 is the hottest in the last 2,000 years in the northern hemisphere. Humans have not felt warmer weather since the beginning of the Roman Empire and the birth of Jesus Christ, according to the latest study.

Overall, last summer was 2.2°C hotter on land compared to the average temperature between AD 1 and 1890 AD, as the industrial revolution was taking place, releasing large amounts of greenhouse gases, a source of climate warming, into the atmosphere.

Summer 2023 is also nearly 4°C hotter than the coldest summer in 536 AD, when ash clouds from volcanic eruptions are thought to cause temperatures to drop drastically.

"When you look at the long history range, you can see how dramatic global warming has been lately," said co-author Professor Ulf B\"untgen of the Cambridge University Department of Geography.

But last year's summer in England was considered normal by the Met Office and only the eighth hottest in their records. 2022 and 2018 were the hottest summers together in England.

Reliable weather records began to be produced by scientific instruments only since 1850 when the industrial revolution began. But by analyzing tree rings, scientists can calculate how hot summer is based on tree ring growth and wood chemical composition.

Trees have a narrower growth period creating narrower rings during periods of cold and wider rings during hot periods.

Earth had the hottest summer of all time when a hot record in August closed three brutal and deadly months in the northern hemisphere.

British society may find it difficult to believe this new record as the country was hit by cold air and rain over the past summer, despite heat waves in mainland Europe.

The researchers wrote that taking into account natural climate variations of around 0.5$C, 2023 was still the hottest summer since the peak of the Roman Empire.

According to Professor B\"untgen, the heat is the result of a combination of record-level greenhouse gases and El Nino weather events.

"2023 is a very hot year, and this trend will continue unless we drastically reduce greenhouse gas emissions," said Professor B\"untgen.

However, the results reported in the journal Nature also show that efforts to limit global warming based on the 2015 Paris Agreement to limit heating to 1.5 degC above pre-industrial levels may have been exceeded.

The researchers calculated that the 19th-century temperature baseline used as a benchmark for measuring global warming could be a few tenths of a Celsius degree cooler than previously thought.

On that basis, the researchers calculated that the 2023 summer conditions in the Northern Hemisphere of 2.07 degC were warmer than the average summer temperatures between 1850 and 1900, in contrast to the current view that global warming was at 1.4 degC higher than the 19th century baseline.

The researchers say that while their results are valid for the Northern Hemisphere, excluding the tropics, it is difficult to get global averages for the same period because of the little data for the Southern Hemisphere.

The Southern Hemisphere also responds to climate change differently, as it is more covered by the sea than the Northern Hemisphere.