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   From: yourdime@outlook.com   
      
   Lava spews from the Sundhnúkur volcano on the Reykjanes Peninsula near   
   Grindavik, Iceland, on June 2, 2024.   
      
   CNN - Mount Tambora changed the world. In 1815, the Indonesian volcano   
   exploded in the most powerful eruption in recorded history, sending an   
   enormous plume of tiny sun-reflecting particles high into the atmosphere,   
   cooling the planet and ushering in disaster.   
      
   What followed was called the “year without a summer:” global temperatures   
   plunged, crops failed, people starved, a cholera pandemic spread and tens   
   of thousands died. Some even credit the volcano with inspiring Mary   
   Shelley to write Frankenstein, while sheltering from unusually cold   
   weather in Switzerland in 1816.   
      
   Many volcanoes have erupted since, but Tambora remains the planet’s most   
   recent massive eruption. More than 200 years later, scientists warn the   
   world may be due another.   
      
   The question is not if, but when, said Markus Stoffel, a climate professor   
   at the University of Geneva. Geological evidence suggests a 1-in-6 chance   
   of a massive eruption this century, he told CNN.   
      
   This time, however, it would happen in a much-changed world, one which is   
   not only more populated but which has also been warmed by the climate   
   crisis.   
      
   The next massive eruption will “cause climate chaos,” Stoffel said.   
   “Humanity does not have any plan.”   
      
   Mount Tambora's deep volcanic crater created by the April 1815 eruption is   
   seen on June 3, 2009.   
      
   Walkers make their way along the craters edge of Mount Tambora on July 19,   
   2006.   
      
   Volcanoes have long shaped our world; they help create continents, have   
   built the atmosphere and can change the climate.   
      
   As they erupt, they eject a cocktail of lava, ash and gases, including   
   planet-heating carbon dioxide, although in quantities dwarfed by those   
   humans produce burning fossil fuels.   
      
   When it comes to climate impact, scientists are more interested in another   
   gas: sulfur dioxide.   
      
   A massive volcanic eruption can propel sulfur dioxide through the   
   troposphere — the part of the atmosphere where weather happens — and into   
   the stratosphere, the layer about 7 miles above the Earth’s surface where   
   planes fly.   
      
   Here, it forms tiny aerosol particles which scatter sunlight, reflecting   
   it back into space and cooling the planet below. These particles “will   
   blow around the world and last for a couple years,” said Alan Robock, a   
   climate professor at Rutgers University who has spent decades studying   
   volcanoes.   
      
   For modern volcanoes, satellite data shows how much sulfur dioxide is   
   released. When Mount Pinatubo in the Philippines erupted in 1991, it   
   propelled roughly 15 million tons into the stratosphere. This wasn’t a   
   massive eruption like Tambora, but it still cooled the world by around 0.5   
   degrees Celsius for several years.   
      
   For older volcanoes, however, “we have very poor data,” Stoffel said.   
   Scientists try to reconstruct these past eruptions using information from   
   ice cores and tree rings, which are like time capsules, storing secrets of   
   the past atmosphere.   
      
   From this they know massive eruptions over the last several thousand years   
   temporarily cooled the planet by about 1 to 1.5 degrees Celsius.   
      
   Tambora, for example, lowered average global temperatures by at least 1   
   degree Celsius. There is evidence the huge Samalas eruption in Indonesia   
   in 1257 may have helped trigger the “Little Ice Age,” a cold period that   
   lasted hundreds of years.   
      
   There are also indications that massive eruptions may affect rainfall,   
   drying monsoon systems including those in Africa and Asia. “The monsoon in   
   the summer happens because the land warms faster than the ocean,” Robock   
   said. A huge volcanic eruption can disrupt the temperature difference   
   between the two.   
      
   ‘A more unstable world’   
   Understanding the impacts of past massive eruptions is vital, but the next   
   will happen in a world that is much warmer than before humans began   
   burning large amounts of oil, coal and gas.   
      
   “It’s a more unstable world now,” said Michael Rampino, a professor at   
   NYU, who investigates links between volcanic eruptions and climate change.   
   “The effects might be even worse than we saw back in 1815.”   
      
   In what may seem a counterintuitive twist, a warmer world may mean massive   
   volcanic eruptions have an even bigger cooling impact.   
      
   That’s because how aerosol particles form and how they are transported is   
   “all dependent on climate,” said Thomas Aubry, a physical volcanology   
   scientist at the University of Exeter.   
      
   As the world warms, the speed at which air circulates in the atmosphere is   
   increasing, meaning aerosol particles are dispersed faster and have less   
   time to grow, Aubry said. Smaller aerosols can scatter sunlight more   
   efficiently than large ones, meaning the cooling impact will be greater.   
      
   Volcanologist Chris Newhall works in the caldera of Mount Pinatubo taking   
   air and water samples on February 18, 1992.   
      
   Indonesia's Mount Ruang spews hot lava and smoke in April 2024.   
      
   Oceans may also play a role. As the surface of the ocean heats up, a layer   
   of lighter, warmer water sits on top and acts as a barrier to mixing   
   between shallow and deeper layers. This may mean eruptions   
   disproportionately cool the ocean’s top layer and the atmosphere above it,   
   Stoffel said.   
      
   Climate change can also affect volcanic systems themselves. Melting ice   
   can lead to increased eruptions, as its disappearance decreases pressure,   
   which can allow magma to rise faster. Scientists have also found more   
   extreme rainfall — driven by climate change — can seep deep into the   
   ground where it can react with magma to trigger an eruption, Aubry said.   
      
   Impossible to predict   
   As the world grapples with global warming, a period of cooling might sound   
   positive. Scientists say the opposite is true.   
      
   Lava erupts from a crater in southwest Iceland near the town of Grindavik   
   in April 2024.   
      
   First, there’s the immediate impact. An estimated 800 million people live   
   within around 60 miles of an active volcano; a massive eruption could   
   erase an entire city. Campi Flegrei, for example, has shown signs of   
   stirring and sits just west of the Italian city of Naples, home to around   
   1 million people.   
      
   Longer-term, the impacts could be cataclysmic. A 1 degree Celsius drop in   
   temperature might sound small, but it’s an average. “??If we look at   
   certain regions, the impact will be much greater,” said May Chim, an Earth   
   scientist at the University of Cambridge.   
      
   Okmok in Alaska, which erupted in 43 BC — the year after Julius Caesar was   
   assassinated — could have cooled parts of southern Europe and northern   
   Africa by up to 7 degrees Celsius, or 13 degrees Fahrenheit.   
      
   Colder weather, less sunlight and shifting rainfall could affect several   
      
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