World seeing unprecedented warming in more than 100,000 years, say experts
Also, July could follow in the footsteps of June, which was categorised as the hottest month on record by the World Meteorological Organization. Photo: iStock July is expected to become the hottest month on record, with temperatures in the first 20 days exceeding the 1979-2021 mean, according to data from the University of Maine’s Climate Change Institute.
“There is a high chance that July will be the hottest month on record,” Akshay Deoras, Research Scientist at the National Centre for Atmospheric Science and the Department of Meteorology, University of Reading, told Down To Earth.
Read more: Heatwaves, droughts, extreme rain may be near permanent in 20 countries at 1.5°C warming
Also, July could follow in the footsteps of June, which was categorised as the hottest month on record by the World Meteorological Organization.
Graph showing the highest daily two-metre air temperatures for each month. Source: Climate Reanalyzer
The global surface temperature was 1.05 degrees Celsius higher than the 20th century average of 15.5°C. “This marked the first time a June temperature exceeded 1°C above the long-term average,” the United States’ meteorological agency, the National Oceanic and Atmospheric Administration, noted.
Some also suspect that the temperatures in July are likely the highest in 100,000 years. “This global heatwave is likely the hottest 20-day stretch in the last 100,000+ years,” Eliot Jacobson, retired professor of mathematics and computer science, tweeted.
Others don’t entirely support this argument. “While this claim may well be correct, there are no detailed temperature records extending back 100,000 years, so we don’t know for sure,” Darrell Kaufman, professor of Earth and Environmental Sciences at Northern Arizona University, wrote in The Conversation.
A 2021 climate assessment report by the Intergovernmental Panel on Climate Change also highlighted that global temperatures are reaching a level unprecedented in more than 100,000 years.
Many researchers note that the current warming trend is worrying. For example, a 2021 study published in journal Nature concluded that the rate and magnitude of modern warming are unusual compared to the past 24,000 years.
Read more: Humid heatwaves in South Asia made 30 times more likely by climate change: Study
Other evidence also suggested that warming around 6,500 years ago pales in comparison to the current temperature rise. One paleoclimate study suggested global temperatures could have been around 0.7°C warmer than in the 19th century. Since then, the world cooled at a rate of 0.08 °C per 1,000 years.
The world has warmed by 1.1°C compared to the pre-industrial period, found the 2021 IPCC report.
“Without rapid and sustained reductions in greenhouse gas emissions, the average temperature of the coming centuries will exceed 1.5 ∘C above pre-industrial temperature and will therefore be warmer than the peak of the last interglacial around 125,000 years ago,” researchers wrote in a paper.
The Earth goes through cycles of glacial (ice age) and interglacial (warm) periods. The last interglacial period occurred about 116,000-129,000 years ago. During this time, temperatures were 1.5°C higher than in the 1971-1990 reference period.
This was followed by a glacial period between about 120,000 and 11,500 years ago. Since then, Earth has been in an interglacial period called the Holocene.
Simultaneous heatwaves have gripped North Africa, the southern United States, southern Europe and China.
In Europe, parts of Greece, eastern Spain, Sardinia, Sicily and southern Italy have seen temperatures above 45°C in the last week.
Read more: Deadly heatwaves threaten to reverse India’s progress on poverty and inequality — new research
Many locations within the midwestern United States may reach their hottest temperatures of the year, said the National Weather Service Climate Prediction Center. Many parts of Florida have been hit by an extended, record-breaking heatwave, the WMO noted.
On July 16, the Sanbao Township Station in Turpan City saw a temperature of 52.2°C, breaking historical records, according to the China Meteorological Administration.
Episodes of concurrent heatwaves are on the rise. The average number of days with at least one large heatwave in the months of May, June, July, August and September has doubled from the 1980s (roughly 73 days) to the 2010s (roughly 152 days) in the northern hemisphere, a 2022 study found.
“Their increasing occurrence is mainly driven by warming baseline temperatures due to global heating, but changes in weather patterns contribute to disproportionate increases over parts of Europe, the eastern United States, and Asia,” the paper read.
This year, high temperatures were driven by heat domes, which formed across the United States, southern Europe and China, Deoras explained.
A heat dome occurs when hot ocean air is trapped by the atmosphere like a lid or cap. It is a kind of high-pressure system, which is characterised by clear conditions, no rain and cloud cover, the expert said.
Read more: Extreme heatwaves can strike regions that were ‘lucky’ to escape record temperatures so far: Study
Climate change, he said, could be amplifying the impacts. “We would know the extent of its impacts only after attribution studies are conducted,” he noted.
Deoras suspects that El Nino, a climate pattern characterised by periods of unusually warm water in the Pacific Ocean, likely did not play a big role in triggering heatwaves.
El Nino is strong when the ocean and atmosphere work together. “While sea surface temperatures are above 1°C, the atmospheric link is not strong,” he said, adding we are yet to see the strong impacts of this climate pattern.
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