In just five years (1845 - 50) the Famine caused over one million deaths and a further million to emigrate - “almost a quarter of the population emigrated to either the New World or the next world in a period of little more than five years.”
In the 50 years prior to the Famine the population of Ireland doubled to over 8 million.
In the 1840s income per capita in Ireland was less than half that of Britain.
A shortfall of just 10% in food supplies can give rise to famine. Food supplies in Ireland were reduced by over 10% in 1845 and by 25 - 30% in 1846, 1847 and 1848.
In 1841 half of the families in rural Ireland lived in one roomed mud cabins. In West Cork the bulk of the population (over 80%) lived in such houses in 1841.
Up to 70% of the one roomed cabins were knocked down or closed between 1841 and 1851, mainly as a result of the Famine.
Two-thirds of the Irish workforce were dependent on agriculture - only one in seven of the population lived in towns and cities.
Between 1846 and 1855 about 2 million people emigrated and a further 2.5 to 3 million in the subsequent 50 years. In total some 4.5 to 5 million emigrated between 1846 and 1915.
In the 1840s there were over 600,000 landless labourers who competed for conacre (Rent £4 - £8 per acre) on which to grow a plot of potatoes to feed their families.
Over 6 million acres of crops were grown in the 1840s compared to a little over one million today.
About 15 million tonnes of potatoes were produced and consumed annually in Ireland in the early 1840s - more than 20 times the tonnage produced today. Less than approximately 0.8 million tonnes of potatoes are consumed annually in Ireland today.
Despite the absence of today’s technology, the yields of potatoes in the pre - Famine period were quite good - it is only in the last 40 to 50 years that potato yields have exceeded those of the pre-Famine period.
Four kinds of potatoes in turn dominated the Irish scene from the 1730s up to the advent of the blight, namely the Black, the Apple, the Cup and the Lumper. During that period the excellent Apple variety was replaced by the not-so-good Cups which yielded 10 - 15% more. The Cup variety, in turn, was replaced by the much inferior Lumper which again yielded 10-15% more. This transition increased yields by 20-30% and made the Lumper the main potato of the poorer people. In the process, the Irish population became totally dependent on a variety which was very susceptible to blight.
In the pre-Famine period the average Irish adult male consumed 14 lbs of potatoes - one stone per day when potatoes were in good supply. Even allowing for the fact that potatoes were eaten at each of the three meals every day, it is difficult to comprehend today how a healthy adult male could stow away say, 70 potatoes, per day and a woman not much less - 55 potatoes per day on average.
In 1846 blight was widespread and potato yields were no more than one tenth the normal yield - enough to feed the population for just one month. Over 3 million tonnes of cereals would be required to replace the shortfall of 13 million tonnes in the potato harvest.
The number in workhouses rose rapidly during the Famine to a peak of 217,000 in 1851.
Almost 80,000 families were evicted between 1846 and 1851. By February 1846, 450,000 people were receiving outdoor relief and the figure almost doubled (830,000) by June of that year.
Over 3 million people collected rations daily from soup kitchens in July 1847.
Almost £5 million was spent on public relief in the autumn and winter of 1846 / 1847.
The number of labourers fell by more than half from about 700,000 in 1845 to 300,000 in 1910.
A chemical for the prevention of potato blight was discovered in 1882 when M. Millardet (France) noticed that the grapes in a vineyard bordering the road, and which had been sprayed with a mixture of copper sulphate (Bluestone) and hydrated lime in order to prevent theft, had remained free from attacks of downy mildew. By 1885, M. Millardet had demonstrated the effectiveness of this treatment in preventing blight in field experiments.
Today, Ireland still has the highest per capita consumption of potatoes amounting to 139 kgs per person per year. In Europe the typical consumption is some 50 to 100 kgs per person per year.