[1][2][3] The famine of 1740–1741 was due to extremely cold and then dry weather in successive years, resulting in food losses in three categories: a series of poor grain harvests, a shortage of milk, and frost damage to potatoes.

By the mid-19th century, potatoes made up a greater portion of Irish diets, with adverse consequences when the crop failed, causing famine from 1845 to 1852.

In 1740, Ireland had a population of 2.4 million people, most of whom depended on grains (oats, wheat, barley and rye) and potatoes as their staple foods.

[7] Diets varied according to village locations and individual income, with many people supplementing these staples with river, lake or sea fish, especially herring, and small game such as wild duck.

At the time social welfare was an entirely private initiative undertaken on a local level by the village or parish, with the government not being oriented to large-scale relief efforts.

Charting its course sharply illuminates how climate events can result in famine and epidemic disease, and affect economies, energy sources, and politics.

This kind of weather was "quite outside the Irish experience," notes David Dickson, author of Arctic Ireland: The Extraordinary Story of the Great Frost and Forgotten Famine of 1740–41.

Ireland was locked into a stable and vast high-pressure system which affected most of Europe in a broadly similar way, from Scandinavia and Russia to northern Italy.

The municipal leaders (mostly Protestant merchants and members of the landed gentry) paid closer attention to the state of urban and rural artisans and tradespeople because of their contributions to the commercial economy on which the landowners depended.

The Lord Lieutenant, the Duke of Devonshire, in an unprecedented move on 19 January 1740, prohibited the export of grain out of Ireland to any destination except Britain.

"Richard Purcell, one of the best rural witnesses of the unfolding crisis, reported in late February [1740] that had the Frost not occurred, there would have been enough potatoes in his district to have kept the country [Ireland] fed until August [1740], indicating a rare local abundance of the crop.

By the end of April, it destroyed much of the tillage crops (wheat and barley) sown the previous autumn, and grains were more important in the diet than were potatoes.

Dickson explains that the "wholesale rise in the price of wheat, oats and barley reflected not just the current supply position, but the dealers' assessment as to the state of things later in the year.

City officials tried to "smoke out hoarders of grain and to police food markets, but prices remained stubbornly high throughout the summer".

The War of the Austrian Succession (1740–1748) began, interrupting trade as Spanish privateers captured ships bound for Ireland, including those carrying grain.

To make conditions worse, blizzards swept along the east coast in late October 1740 depositing snow and returned several times in November.

Some major landowners, such as the widow of Speaker William Conolly, builder of Castletown House, distributed food and cash during the "black spring" of 1741 on their own initiative.

The widow Conolly and other philanthropists hired workers to develop infrastructure or do work associated with local improvements: such as building an obelisk, paving, fencing, draining, making roads or canals, and cleaning harbours.

In Drogheda, the Chief Justice of the Irish Common Pleas, Henry Singleton, a citizen of the town, donated much of his private fortune for famine relief.

The normal death rate tripled in January and February 1740, and burials averaged out about 50% higher during the twenty-one-month crisis than for the years 1737–1739, according to Dickson.

Based on contemporary accounts and burial parish records, famine-related deaths may have totalled 300,000–480,000 in Ireland, with rates highest in the south and east of the country.

As conditions eased, "the population entered into a period of unprecedented growth", although additional famines occurred during the eighteenth century.

[20] Dickson notes that an upsurge in migration out of Ireland in the years after the 1740–1741 crisis did not take place, perhaps in part because conditions improved relatively quickly although the most likely primary reason was that a transoceanic voyage was far beyond the means of most of the population at this time.