One day a few weeks ago, Magnus was playing a new variant of his favourite game, Belittling the Sister. This is actually something he could do to just about anybody, being now somewhere north of 6’ 3”, but most of us don’t stay around for long enough. His sister, however, being far too sweet -natured for her future good, falls for it every time. “Hey, Dolly, let’s play, ‘Where is?’” “Okay”, comes the unwary response. “Where’s  Ouagadougou  ? ’ ‘Japan?’ ‘No! Burkina Faso. Where’s Burkina Faso?’ ‘Japan?’ ‘No! Africa. Where’s Africa?’ ‘Japan?’ She’s a born gambler, my darling daughter.

Having witnessed a few rounds of this, I decided to ask for a  globe  as a Christmas present. It’s always hard to think of things that will both enhance my life and be given house room by Mr Fixit, and thus it arrived occluded by hurt bemusement at the non-existence of German-made monochrome globes with stainless steel trim and  Herbert Bayer  lettering. But he made the best of his choices, and our family globe now glows happily in the dining zone, amongst the fruit bowls and half-accomplished  domestic tasks  I might finish if I ever visited that end of the table.

I have noticed that its geography, and indeed its borders, are pretty much fixed, which is what you’d hope of a globe under conventional circumstances. In the Normal/Fixit household, however, geography shifts subtly with the arrival of winter. Most of the year, our understanding of Europe is the same as yours, and I attempt to corral our food purchases within it. Exceptions are made for (fairly-traded) coffee,  chocolate , tea and bananas, which seem to be an indispensable part of our diet, and afford enjoyable weekly opportunities for Mr Fixit to announce a visit to the verdant banana groves of Camden Town, aka Sainsbury’s.

The rest can be found close to hand, and if it means we never eat pineapple or limes (and why are there no limes in Europe, anyway?), it also means we – or some of us – well, I – REALLY enjoy the tomatoes and raspberries I haven’t tasted for months.

Some people argue that this food parochialism is depriving less developing countries of vital revenue; that  Peruvian farmers  need me to buy their asparagus. I think what Peruvian farmers probably need is fair trade and fewer subsidies, and so does Mike Berners Lee. His excellent book,  ‘How Bad are Bananas? ’, calculates, in ascending order of shame, the carbon footprint of everything from sending a text message (0.014g) to a flight in the Space Shuttle (4,600 tonnes), with handy equivalents to press home the point. Flying in the Shuttle, which is fortunately or unfortunately not an option any more, has a footprint equivalent to half a sheet of recycled toilet paper for everybody in the world. That’s an image you won’t forget in a hurry.

One upside of our restricted diet is supposed to be the blissful simplicity of less choice, which, as we all know, is the  Koh I Noor  of unattainable dreams – at least to all of us in the developed world, who can return to more choice any time it turns out to be useful. Theoretically, this local and seasonal restriction saves us endless hours of agonised indecision in the overstocked aisles of the supermarket, which we can then redeploy hand-pollinating our  heirloom quinces .

Anybody who has ever seriously attempted a life of ethical decisions knows better. We didn’t start out with white hair full of bald patches, and mad, staring eyes. We got that way because of people like Mike. In Mike’s world, nothing is ever that simple.

Returning to asparagus, Mike tells us that a cyclist fuelled by Peruvian asparagus might as well be popping to the shops in a  Lamborghini Countach . The full calculation goes as follows: cycling one mile powered by bananas emits 65g of Co2e; add milk, and it goes up to 90g. Swapping to bacon-power shoves it up to 200g – though a bacon-only diet might considerably diminish the health benefits of cycling. However, the conflicted, or possible perfectly-balanced, person who cycles everywhere but eats only cheeseburgers (260g) turns out to emit less than 1/10 of the calories of your smug veggie on out-of- season asparagus (2,800g per mile, and a very whiffy cycle for anybody downwind).

‘Fine!’, you might say. ‘We’ll just ignore everything that has to come by air’.

Not so fast! Elsewhere in his admirably-detailed research, Mike tells us about  flowers  .  A rose grown in the blazing heat of Kenya has a dainty carbon footprint of 350g, even including its business class flight. Whereas your out of season rose from a heated Dutch greenhouse, even if it walked here, has a whopping 2.1kg footprint.

That ‘out of season’ thing holds the key. You can’t even eat local either, once it has to be heated (or refrigerated). Come October, no more tomatoes. Come December, no more apples. Come January, no more pretty much everything, including the will to live.

The idealism of Mike’s world view can be summed up in his last word on asparagus: ‘When asparagus is out of season, which is most of the time, try to favour low-carbon options such as kale, carrots, parsnips, swede or leeks.’ And then he adds, no doubt to reassure us that he is human enough to have found a mate, ‘My children prefer their carrots raw’, reminding us – as though we needed it, ha ha! – that in doing so, they save several vital grams of carbon. Of course, this is what we should all be doing. On  December 25th  ,  for example, every right thinking family in the land tucked into a nourishing raw root vegetable medley, brightened with raw foraged mushrooms and seaweed vinegar, on a bed of dewy nettles.

But Mr Fixit is not Mike, and our children are not his. And for some reason the availability of food has been organised all the wrong way round, so that the most miserable weather coincides with the most miserable food, including the disappearance of almost everything apart from those parsnips, carrots and leeks.

There is the odd twinkle in the gloom: inexplicably, avocadoes and mangoes ripen in Spain in December, and the arrival of the first  blood oranges  is a little Christmas all by itself.  But there comes a point – around now, in fact – when family harmony requires the map of Europe to self-adjust. Most of the year, it’s clear that France, Spain and Italy are in Europe, and Chile, Peru and South Africa are not. By late January, however, I’m beginning to wonder about the margins. Referring to our excellent and infallible globe, the  Blue Nile , for instance, may not be technically European, but it’s quite near Morocco, and Morocco is practically in Spain. And Spain is definitely in Europe. So we can have beans from Egypt, and sweet potatoes from Morocco.

After a few more weeks of root vegetable medley, I start to ruminate – about language. Could it not rightly be said that the real geography of the modern world is not measured by distance, but by  common culture ? On that basis, the South African peaches are about as local as you could get. Those peaches and our carrots are practically cousins!

By March, even the inclusion of most of the world’s land mass in what I like to call Greater Europe can’t assuage our collective yearnings. It’s time to take the big picture view. Which is worse, flying a few lemons from Mexico to Camden, or flying the entire family to Mexico to dress its salad? Put that way, there’s no argument. All those  colours  on that globe over there don’t mean anything. They’re just like the aisles in Sainsbury’s, coded to let you know what’s where. Now, children, show me where the asparagus comes from again? It’s definitely somewhere in Europe .