Krakatoa eruption environmental impact
The 1883 eruption of Krakatoa, located in the Malay Archipelago, was one of the most powerful volcanic events in recorded history, leading to significant environmental impacts. Occurring on August 26-27, the eruption destroyed two-thirds of the island and resulted in the loss of over 36,000 lives, primarily on nearby Java and Sumatra. The eruption expelled approximately 21 to 25 cubic kilometers of volcanic material into the atmosphere, causing global cooling by blocking sunlight and reducing temperatures by about 0.5 degrees Celsius for up to five years. This cooling effect also contributed to a drop in sea levels, which did not return to previous heights until the mid-20th century. The event caused vivid atmospheric phenomena, such as red sunsets, visible for years across the globe, sparking scientific interest in high-altitude wind systems. Over time, Krakatoa's landscape began to recover, with plants and animals gradually recolonizing the area. The region was later designated as a nature reserve and part of a UNESCO World Heritage Site, reflecting its ecological significance and the ongoing study of volcanic landscapes. The eruption's legacy continues to inform scientists about volcanic activity and environmental recovery processes.
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Krakatoa eruption environmental impact
THE EVENT: Massive volcanic eruption that took place in the Malay Archipelago
DATES: August 26-27, 1883
The eruption of the volcano Krakatoa ejected tons of rock, ash, and gases into the atmosphere, cooling the planet and causing sea levels to fall.
The volcano Krakatoa (or Krakatau) erupted in a series of four spectacular explosions on August 26 and 27, 1883. The eruption was the fourth largest in recorded history and destroyed two-thirds of the island—also known as Krakatoa—on which the volcano stood. The cataclysm resulted in more than 36,000 deaths, most of them on the nearby islands of Java and Sumatra, and had profound worldwide consequences as well.
Krakatoa’s eruption produced a shock wave that passed around the earth seven times, and its sound was clearly heard 4,777 kilometers (2,968 miles) away. The tsunamis that resulted from the eruption, which caused many deaths in the immediate vicinity, were detected as ripples as far away as the English Channel. An estimated 21 to 25 cubic kilometers (5 to 6 cubic miles) of material was ejected into the atmosphere by the volcano, some of it as high as 48 kilometers (30 miles). Ash drifted down on ships thousands of miles away, but much of the finer material remained floating in the and was carried around the earth. Vivid atmospheric effects of the eruption, including red and yellow sunsets and halos around the sun and moon, were reported from widely scattered locations for three years. Such observations provided scientists with their first proof of a worldwide system of high-altitude winds.
Of greater importance to the larger environment, sulfur dioxide (SO2) gas emitted during the eruption combined with water vapor to create droplets of sulfuric acid (H2SO4) in the upper atmosphere. Together with floating ash, these droplets reduced the sunlight striking the earth by about 1 percent for two years, cooling the planet as much as 0.5 degree Celsius (0.9 degree Fahrenheit) for approximately five years. In 2006 P. J. Gleckler and five colleagues determined that the reduction in sunlight also caused the oceans to cool and, as a result, sea levels to fall. Sea levels regained their previous height only during the middle of the twentieth century.
The fragments of Krakatoa remaining after the eruption were covered by as much as 40 meters (131 feet) of ash, and it was assumed that every living on the island had died. According to an article in New Scientist in 2024, experts believe that the green sunsets reported after the eruption were most likely the result of sulfur aerosols that the volcano thrust into the stratosphere. For scientists concerned with the recolonization of such a landscape by plants and animals, the site became a living laboratory. A few months after the eruption, a small spider was observed, and six years later a monitor lizard and a variety of insects were noted. Within a few decades, trees had sprouted and grown to more than 12 meters (39 feet) in height.
In late June, 1927, fishermen noticed steam rising from the sea above the collapsed portions of Krakatoa, indicating a renewal of volcanic activity. On January 26, 1928, a new island appeared above the surface of the sea and was soon named Anak (child of) Krakatoa. It has since grown steadily and has erupted several times. The Krakatoa area was declared a nature reserve in 1921, and it was later made a part of Indonesia’s Ujung Kulon National Park. In 1991 the park was designated a World Heritage Site by the United Nations Educational, Scientific, and Cultural Organization (UNESCO).
Bibliography
Dinneen, James. "Eerie Green Sunsets after 1883 Krakatoa Eruption Finally Explained." New Scientist, 4 Mar. 2024, www.newscientist.com/article/2420411-eerie-green-sunsets-after-1883-krakatoa-eruption-finally-explained/. Accessed 19 July 2024.
Gleckler, P. J., et al. “Krakatoa’s Signature Persists in the Ocean.” Nature 439 (February 9, 2006): 675.
Simkin, Tom, and Richard S. Fiske. Krakatau, 1883: The Volcanic Eruption and Its Effects. Washington, D.C.: Smithsonian Institution Press, 1983.
Thomas, Heather. "Krakatoa: Fire in the Sky." Library of Congress, 19 May 2022, blogs.loc.gov/headlinesandheroes/2022/03/krakatoa/. Accessed 19 July 2024.
Winchester, Simon. Krakatoa: The Day the World Exploded, August 27, 1883. New York: HarperCollins, 2003.