Volcanism is often implicated in periods of abrupt cooling. After the 1991 eruption of Mount Pinatubo in the Philippines, for instance, global temperatures dropped by half a degree Celsius due to airborne particulate matter blocking solar radiation. However, these effects don't normally last more than a few years. Yet, a recent study blames volcanism for a 500-year cold period referred to as the Little Ice Age.
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Beginning around the end of the Middle Ages and lasting into the early 19th century, unusually cold conditions blanketed much of the Northern Hemisphere. This period is known as the Little Ice Age. When exactly this period began, and how it was sustained for so long are matters of much debate. The culprit, according to a new study put forth by climate scientist Gifford Miller of the University of Colorado, is volcanism. How can a short-lived event like a volcanic eruption trigger cooling that lasts for centuries?
Find out at http://www.earthmagazine.org/article/volcanoes-sparked-and-prolonged-little-ice-age.
Contacts and sources:
Megan Sever
American Geological Institute
The Frozen Thames, 1677
Beginning around the end of the Middle Ages and lasting into the early 19th century, unusually cold conditions blanketed much of the Northern Hemisphere. This period is known as the Little Ice Age. When exactly this period began, and how it was sustained for so long are matters of much debate. The culprit, according to a new study put forth by climate scientist Gifford Miller of the University of Colorado, is volcanism. How can a short-lived event like a volcanic eruption trigger cooling that lasts for centuries?
The
Little Ice Age brought colder winters to parts of Europe and North America.
Farms and villages in the Swiss Alps were destroyed by encroaching glaciers
during the mid-17th century. Canals and rivers in Great Britain and the
Netherlands were frequently frozen deeply enough to support ice skating and
winter festivals. The first River Thames frost fair was in 1607; the last in
1814, although changes to the bridges and the addition of an embankment
affected the river flow and depth, hence diminishing the possibility of
freezes. Freezing of the Golden Horn and the southern section of the Bosphorus
took place in 1622. In 1658, a Swedish army marched across the Great Belt to
Denmark to invade Copenhagen. The winter of 1794-1795 was particularly harsh,
when the French invasion army under Pichegru could march on the frozen rivers
of the Netherlands, while the Dutch fleet was fixed in the ice in Den Helder
harbour. In the winter of 1780, New York Harbor froze, allowing people to walk
from Manhattan to Staten Island. Sea ice surrounding Iceland extended for miles
in every direction, closing harbors to shipping.
Find out at http://www.earthmagazine.org/article/volcanoes-sparked-and-prolonged-little-ice-age.
Megan Sever
American Geological Institute
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