Wednesday, May 29, 2013

Little Ice Age Timeline 1250-1850

Based on 5/26/2013 Forbes article by Peter Ferrara

950 - 1250 AD
Medieval Warm Period

1250 AD
Ice packs began showing up farther south in the North Atlantic.
Glaciers also began expanding on Greenland, soon to threaten Norse settlements on the island.

1275 - 1300 AD
Glaciers began expanding more broadly, according to radiocarbon dating of plants killed by the glacier growth.

1270 - 1475 AD
Oxygen/isotope analysis from the Pacific Islands indicates a 1.5 degree Celsius temperature decline.

1270 - 1380 AD
Tree ring data from Patagonia in South America show cold periods.

1280 - 1350
A period of sharply lower sunspot activity known as the Wolf Minimum.

1300 AD
Summers began cooling in Northern Europe, negatively impacting growing seasons.

1315 - 1317
The Great Famine.

Expanding glaciers and ice cover spreading across Greenland began driving the Norse settlers out.

The last, surviving, written records of the Norse Greenland settlements, which had persisted for centuries, concern a marriage in the church of Hvalsey, today the best preserved Norse ruin.

1460 - 1550
Even lower sunspot activity known as the Sporer Minimum.

Colder winters began regularly freezing rivers and canals in Great Britain, the Netherlands and Northern France, with both the Thames in London and the Seine in Paris frozen solid annually.

1500 - 1800
A 3,000 year temperature reconstruction based on varying rates of stalagmite growth in a cave in South Africa indicates a colder period.

1520 - 1670
Tree ring data from Patagonia in South America show a second cold period

1570 - 1820
Sediment cores from Lake Malawi in southern Africa show colder weather.

1600 - 1800
Ice cores from the Andeas mountains in South America show a colder period.

The first River Thames Frost Fair was held.

Early European settlers in North America reported ice persisting on Lake Superior until June.

1645 - 1715
The number of sunspots declined to zero for the entire time.
This is known as the Maunder Minimum, named after English astronomer Walter Maunder

January 1658
A Swedish army marched across the ice to invade Copenhagen.

Historic snowstorms in Lisbon, Portugal.

1675 - 1766
Spanish explorers noted the expansion of the San Rafael Glacier in Chile.

End of the 17th century
Famines had spread from northern France, across Norway and Sweden, to Finland and Estonia.

Early 1700's
The Franz Josef glacier on the west side of the Southern Alps of New Zealand advanced sharply during the period of the Little Ice Age, actually invading a rain forest at its maximum extent.
The Mueller glacier on the east side of New Zealand’s Southern Alps expanded to its maximum extent at roughly the same time.

Snowstorms in Lisbon, Portugal

1777 - 78
The American Revolutionary Army under General George Washington shivered at Valley Forge.

New York harbor was frozen in the winter.

1790 - 1830
The Dalton Minimum, another period of well below normal sunspot activity.

Early 19th century
Glaciers in Glacier National Park in Montana cease their advance.

The last River Thames Frost Fair was held.

Late 19th century
The increase in global temperatures reflects the end of the Little Ice Age.

1915 - 1945
Ocean temperature cycles, and the continued recovery from the Little Ice Age, rose global temperatures from point when CO2 emissions were much lower than in recent years.
The global temperature trends since then have followed not rising CO2 trends but the ocean temperature cycles of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Every 20 to 30 years, much colder water near the bottom of the oceans cycles up to the top, where it has a slight cooling effect on global temperatures until the sun warms that water.
That warmed water then contributes to slightly warmer global temperatures, until the next churning cycle.

1945 - 1970's
The change to a cold ocean temperature cycle, primarily the PDO, is the main reason that global temperatures declined, despite the soaring CO2 emissions during that time from the postwar industrialization spreading across the globe.

1970's - 1990's
The 20 to 30 year ocean temperature cycles turned back to warm, which is the primary reason that global temperatures warmed during this period.

1998 - 2013
Warming ended and global temperatures have stopped increasing, if not actually cooled, even though global CO2 emissions have soared over this period.

2000 - 2010
The world added roughly 100 billion tonnes of carbon to the atmosphere between 2000 and 2010. That is about a quarter of all the CO2 put there by humanity since 1750.