Weatherwatch: the Irish potato famine

Stephen Moss looks at how weather caused famine in mid-19th century Ireland

As the potato harvest began in Ireland in 1845, prospects were looking good for a bumper crop. This was just as well, for Ireland's population had increased dramatically in the previous decades to more than 8 million. But when people dug up the potatoes, all they found was a black sticky mess – the result of potato blight.

Potato blight is a disease whose spores are carried in the air. It is estimated that less than half the potato crop that year was edible, and the following two years saw renewed outbreaks. The blight was not confined to Ireland, it also reached southern Britain and the Low Countries. But the combination of a soggy climate, and the dependence on the potato as a staple diet, meant that the Irish suffered far more than most.

The resulting famine changed both Ireland and the rest of the world. More than one million people died of starvation, and another million emigrated, mostly to the US. Political and economic factors were certainly to blame for the devastating effects of the blight. But the catalyst that enabled it to spread was the weather. Ireland has a damp, maritime climate, thanks to its geographical position on the extreme western edge of the Eurasian landmass, jutting out into the Atlantic Ocean.

The summer of 1845 was especially wet, with high humidity – ideal conditions for the spores of the blight to develop on the leaves. Persistent rain then washed them into the soil, where they infected the growing potato tubers.

• This article was amended on 25 September 2011. The original put Ireland's population in 1845 at more than 3 million. This has been corrected.


Stephen Moss

The GuardianTramp

Related Content

Article image
Weatherwatch: Ophelia's arrival hints at a new vulnerability for Europe
An off-the-charts hurricane that tracked to Ireland points to climate change pushing ‘tropical oceans’ northward and putting the continent in the firing line

Paul Brown

19, Oct, 2017 @8:30 PM

Article image
Weatherwatch: soggy end to June across the UK and Ireland
Parts of north-west England had three times more rainfall than usual and heavy downpours caused landslides in Ireland

Azure Prior

08, Jul, 2020 @8:30 PM

Article image
Weatherwatch: come to County Kerry, the weather's Goldilocks!
If you like it not too hot and not too cold, Valentia Island in the west of Ireland may be the place for you

Stephen Moss

26, Jun, 2019 @8:30 PM

Article image
Weatherwatch: Melting Arctic ice triggers winter storms, study finds
Meltwater from Greenland creates freshwater pond at the ocean surface that whips ups storms in northern Europe

Kate Ravilious

24, Jul, 2020 @8:30 PM

Weatherwatch: Stephen Davenport on copious rain and severe gales in South Australia

Stephen Davenport: A vigorous low pressure system brought copious rain and severe gales to South Australia

Stephen Davenport, MeteoGroup

27, Apr, 2009 @11:01 PM

Weatherwatch: Paul Brown

Paul Brown: The warm sunshine of last weekend set off the first swarm of the year from a neighbour's chimney

Paul Brown

10, May, 2009 @11:01 PM

Weatherwatch: 16 February 2009

Paul Brown: Vast numbers of people owned skates in the 19th century because every winter there were opportunities to use them

Paul Brown

16, Feb, 2009 @12:01 AM

Weatherwatch: 9 February 2009

Paul Brown: The most celebrated excuse for late trains was made on 11 February 1991

Paul Brown

09, Feb, 2009 @12:01 AM


Lawrence of Arabia sat by a blaze of olive logs, listening to two musicians playing Kurdish war-songs, when the storm suddenly broke

Tim Radford

10, Oct, 2008 @11:01 PM


Weatherwatch: A proverb says that March 'comes in like a lion and goes out like a lamb'

Stephen Moss

19, Mar, 2009 @12:01 AM