Today’s global population is 7.5bn people. This population looks set to increase by 30% between now and 2050, in major part owing to longevity.
That increase is ~85M people a year. Or some 9,700 people an hour.
Each person needs, on average, 2000 calories a day, most of which we get from carbs and fat. Forget the world population for a moment, think of Birmingham’s requirement: 2000 x 1.1M = 2.2bn calories every day. And the rest:
Our diet, roughly speaking, should be 50% fruit and vegetables, 25% carbs and 25% fats and proteins.
There’s an interesting factoid about protein. Essential for us, we don’t need much, only around 40g per day. A large steak contains ~85g of the stuff. Our bodies, though, can’t store it, so we excrete any excess (which is why people with kidney problems need watch their protein intake).
Protein deficiency? Unlikely in the UK. Protein deficiency globally? Yup. Scientists are much taxed about how we will be able to grow enough protein for everyone.
As said earlier, the UK demand is met by 60% of food grown here, and 40% is imported. Of that 40%, 70% is from the EU and a further 27% from countries with which the EU has a Preferential Trade Agreement (PTA).
Brexit thus poses a significant threat to our food security.
And, on top of all that, without being part of the single market or the Customs Union, our agricultural sector will be badly affected, particularly livestock farming as tariffs, non-tariff barriers and quotas take their toll. (For papers, articles et al on Brexit and the food system, see this list here.)