The annual average temperatures in the Northern Hemisphere came down by around 1 degree Celsius during one of the most powerful eruptions in the 19th century. Now, after nearly 200 years, scientists have identified the ‘mystery volcano’ that cooled down the Earth’s climate when it erupted in 1831.

In their research, published in Proceedings of the National Academy of Sciences journal on Monday, the scientists have linked the 1831 eruption to an island volcano in the northwest Pacific Ocean.

The ‘mystery volcano’ was Zavaritskii, also spelled as Zavaritsky. It is situated on Simushir Island, a part of the Kuril Islands archipelago — a disputed area by Russia and Japan. As per their analysis, the last eruption from Zavaritskii was in 800 BC.

Although researchers were aware of the year of this historic eruption, they could not trace the location of the volcano until recently when they sampled ice cores in Greenland.

The eruption happened during the last gasp of the Little Ice Age, considered one of the coldest periods in the Earth’s history in the past 10,000 years. As part of their research, the scientists looked into the cores’ layers to examine sulfur isotopes, tiny volcanic glass shards and grains of ash that had been deposited between 1831 and 1834.

To map particles’ trajectories, the researchers analysed radioactive dating, geochemistry, and computer modelling.

Dr William Hutchison, a principal research fellow in the School of Earth and Environmental Sciences at the University of St. Andrews in the UK and the lead author of the study, said, “For many of Earth’s volcanoes, particularly those in remote areas, we have a very poor understanding of their eruptive history”.

Since Zavaritskii is situated on an extremely remote island between Japan and Russia, “no one lives there and historical records are limited to a handful of diaries from ships that passed these islands every few years,” Hutchison told CNN via email.

According to the latest study, no one previously thought Zavaritskii was behind the 1831 eruption since there was very little information about its activity during the 19th century. Instead, they considered other volcanoes, especially those located closer to the equator, like the Babuyan Claro volcano in the Philippines.

According to a recent research, the summer months in 2023 were on average 2.2 C (4 F) warmer than the estimated average temperature across the years 1 to 1890.
| Photo Credit: The Hindu

The intense northern hemisphere summer heat that drove wildfires across the Mediterranean, buckled roads in Texas and strained power grids in China last year made it not just the warmest summer on record – but the warmest in some 2,000 years, new research suggests.

The stark finding comes from one of two new studies released on Tuesday, as both global temperatures and climate-warming emissions continue to climb.

Scientists had quickly declared last year’s June to August period as the warmest since record-keeping began in the 1940s.

New work published in the journal Nature suggests the 2023 heat eclipsed temperatures over a far longer timeline – a finding established by looking at meteorological records dating to the mid-1800s and temperature data based on the analysis of tree rings across nine northern sites.

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

Last year’s summer season temperatures on lands between 30 and 90 degrees north latitude reached 2.07 degrees Celsius (3.73 degrees Fahrenheit) higher than pre-industrial averages, the study said.

Based on tree ring data, the summer months in 2023 were on average 2.2 C (4 F) warmer than the estimated average temperature across the years 1 to 1890.

The finding was not entirely a surprise. By January, scientists with the European Union’s Copernicus Climate Change Service were saying the year of 2023 was “very likely” to have been the warmest in some 100,000 years.

However, proving such a long record is unlikely, Esper said. He and two other European scientists argued in a paper last year that year-by-year comparisons could not be established over such a vast time scale with current scientific methods, including gleaning temperature data from sources such as marine sediments or peat bogs.

“We don’t have such data,” Esper said. “That was an overstatement.”

Last year’s intense summer heat was amplified by the El Nino climate pattern, which typically coincides with warmer global temperatures, leading to “longer and more severe heatwaves, and extended periods of drought,” Esper said.

Heatwaves are already taking a toll on people’s health, with more than 150,000 deaths in 43 countries linked to heatwaves for each year between 1990 and 2019, according to the details of a second study published on Tuesday in the journal PLOS Medicine.

That would account for about 1% of global deaths – roughly the same toll taken by the global COVID-19 pandemic.

More than half of those heatwave-related excess deaths occurred in populous Asia.

When the data are adjusted for population size, Europe had the highest per capita toll with an average of 655 heat-related deaths each year per 10 million residents. Within the region, Greece, Malta, and Italy registered the highest excess deaths.

Extreme heat can trigger heart problems and breathing difficulty or cause heat stroke.

The European Space Agency (ESA) on Saturday released a satellite picture of day and night split in half on Earth’s surface. The image posted on X, formerly Twitter, shows the crossing of the Sun in the celestial equator in the sky and bringing autumn to the Northern Hemisphere. Sharing the picture, the space agency wrote, “Winter is coming. Day and night are split in half today, as the Sun crossed the celestial equator in the sky at 07:50 BST/08:50 CEST marking the autumn equinox in the Northern Hemisphere. This #Meteosat image was taken at 09:00 BST/10:00 CEST this morning.”

Winter is coming

Day and night are split in half today, as the Sun crossed the celestial equator in the sky at 07:50 BST/08:50 CEST marking the autumn equinox in the Northern Hemisphere.

This #Meteosat image was taken at 09:00 BST/10:00 CEST this morning (pic: EUMETSAT) pic.twitter.com/t7oUI36ai4

— ESA (@esa) September 23, 2023

Since being shared, the post has amassed a lot of reactions from social media users.

“This is an interesting post !” said a user.

“Incredible,” said another person.

“The autumn equinox has begun in the Northern Hemisphere. Shown here, a grand image of Earth from Meteosat in space with Africa, Europe, and the Middle East positioned to the front,” commented another user.

A person added, “Amazing; I had no idea the countries of the world were drawn onto the Earth like that.”

As per Space.com, Autumn began astronomically in the Northern Hemisphere and spring started in the Southern Hemisphere. “The sun is currently migrating south, having spent the previous six months shining directly on the northern half of our planet. So, at the official start time of autumn, the sun would appear directly overhead from a ship in the Laccadive Sea, positioned on the equator, 170 miles (275 kilometres) northeast of Addu City in the Maldives,” the website said. 

The Earth’s axis is tilted either towards or away from the sun for the majority of the year. It follows that the planet’s northern and southern portions receive different amounts of warmth and light from the sun. The Earth’s axis and orbit align at the equinox, distributing sunlight equally to both hemispheres.

Two Latin words that signify equal and night make up the word equinox. This is due to the fact that on the equinox, day and night are almost equal in length. However, depending on where you are on the planet, one may get a few some extra minutes.