Latitude: A perspective on UK food security

Birmingham is just below the 53rd parallel, marked by a red line in the map below, nearly two thirds of the way up from the Equator towards the North Pole.

The most northerly part of the UK lies only 400 miles from the Arctic Circle. (1)

The UK, however, has a temperate climate despite our comparative proximity to the Arctic. The reason why is the Gulf Stream.

The Gulf Stream
It brings warm, west, westerly winds to our misty northern isles. This is why it’s much warmer here than at the 53rd parallel the other side of the Atlantic running between Newfoundland and Labrador.

Because of the Gulf Stream, UK winters are warmer than those the European continent.

Birmingham is further north than the northern-most point in Ukraine; their bitter winters are all too evident in the war reports we see. Glasgow and Edinburgh are both marginally further north than Moscow with its snow-laden winters; Glasgow is noticeably warmer (and wetter!) than Edinburgh because its western location means it’s more exposed to the Gulf Stream.


A temperate climate surrounded by the sea means it’s good for growing a lot of produce here. (2)

This produce includes grass, which is why livestock and dairy thrive here. (3)

Not much fresh produce (fruit and veg) of any kind, however, can be grown here during the ‘hungry months’. (4)

  • Getting five-a-day of fresh veg only is just about possible through the winter months. (5) (6)
    • As the table in footnote (2) shows, it’s impossible to get fresh fruit, let alone the ideal ten-a-day portions of fruit and veg by ‘eating local’.
    • To achieve that, we need to import produce or invest heavily in horticulture micro-climate technologies.
  • Our climate varies across the UK, in part due to exposure to the Gulf Stream, in part due to altitude.
  • A contributory factor to today’s shortages are due to high energy costs.
    • Growers under glass in both the Netherlands and here in the Lea Valley planted 50% less than usual because, without subsidies, already tight margins couldn’t be met. (7) (8)


Unusual weather events in Spain and Morocco (9)
One of factors generating the current shortages of fresh produce here is ‘unusual’ weather in Morocco and Spain. (Climate change means ‘unusual’ weather will be, ah-em, usual.)

  • There were droughts in important growing areas in both Morocco and Spain last year, which meant growers reduced planting. Snowfalls and flash flooding hit central Morocco, damaging crops. Earlier this month, crops in Almeria in Spain suffered frost damage.
    • Remember, too, that getting produce from Morocco to the UK requires two sea crossings. And yup, earlier this month storms hit ferry crossings from Morocco to Spain, damaging produce on board, and delaying delivery.
      • Produce from Morocco to the UK takes an extra one or two days during the best of times. Less fresh than EU27 produce, therefore, when it hits our shelves.


AMOC: What if/when global heating leads ro the Gulf Stream failing?
The Atlantic Meridional Overturning Circulation (AMOC) is a system of ocean currents that circulates water within the Atlantic, bringing warm water north (to us!) and cold water south.

The flow of war water originates in the Gulf of Mexico, hence the term ‘Gulf Stream’.

But AMOC is currently weakening, due to three main reasons: the intensification of rainfall at high latitudes, the melting of the ice-cap over Greenland, and the warming of the Earth’s surface. The changes in the world’s monsoon systems are likely due to this weakening.

In the Global Food Security paper, Environmental tipping points and system dynamics, the authors state

  • If the collapse happened rapidly, it would cause unprecedented losses in global production:
    • Some of the impacts on food production [  ] loss of significant European crop and grassland production, perhaps as much as a third, extending across to Russia.
    • In addition, significant losses of rice production in India, changes in rainfall in Sub-Saharan Africa, and drying in Central S America, and the corresponding losses in productivity in soya and sugar.

Moreover, historical shortfalls in calorie production, much less than the magnitude that may occur with a sudden AMOC collapse, have led to price spikes, famine, civil disorder and social breakdown.

They conclude: “Early warning to allow mitigation and/or adaptation is key to minimising the global disruption this might cause.”

Amen to that.


(1) The northern-most tip of the UK, Out Stack in the Shetland Isles, is almost exactly two-thirds of the way from the equator to the North Pole, 60 degrees 51′ to be precise. The most southerly, the Isles of Scilly, are on the 50th parallel, at 49 degrees 51′.

(2) Produce requiring more longer and hotter periods of sunshine than our climate allows cannot be grown here; for example, citrus fruits. Others, such as tomatoes of some soft fruit, can only be grown for a short period or in cloches  under glass. The west side of the UK is warmer than the east, again because of the Gulf Stream. This affects what crops can be grown, and the quality of grass. The UK is good for growing grass, but it varies in quality; e.g. Cheshire, with its warm, wet climate, is particularly good for dairy cattle, whereas the Yorkshire wool trade was close to grass suitable for sheep.

(3) Although much of the UK climate and terrain is good livestock and dairy, the economic set-up doesn’t work, as Ed Salt, a goat dairy man, explained to Nick Booth and myself in this podcast.

(4) The ‘hungry months’ run from November through to April.; see this blogpost. It contains this useful table:

(45 The first time the five-a-day advice was challenged as being insufficient was in 2014 when this article in the Journal of Epidemiology and Public Health appeared by Dr Oyinlola Oyebode (now at Queen Mary University London then at University College London) and her colleagues.
They concluded that that 7-a-day or more gave significantly more benefits; see this UCL press release about the article.

(6) In 2017, a team of researchers led by Dr Dagfinn Aune at Imperial College, London, showed conclusive evidence that, although even the recommended five-a-day reduced disease risk, the greatest benefit came from eating 800g of FFV a day, equivalent to ten portions.
see their article in the International Journal of Epidemiology, and this Imperial College press release about it.

(7) See this Ed Conway Substack article: It’s the Energy, Stupid.

(8) There are high barriers to entry in horticultural production because of the substantial capital investment needed and, because profit margins are slim, returns on investment are non-existent. This is why the Government’s espoused reliance on the private sector to invest in the sector will not work.

(9) ‘Extreme weather events’ is the second suite of events in this table from my post: Tomato-gate? We ain’t seen nothing yet!

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