Across Europe, shoppers have been shocked to learn that meat products have been contaminated with horse. We have unwittingly been eating horse for months, perhaps years.
This has resulted in part from the globalisation of food; supply chains have become increasingly complex, and traceability has become trickier. It is obviously bad that we don't know the true content of our food, but is it actually bad to eat horse? What makes other meats so much better?
Meat production, with current animals, methods and volumes, is inherently unsustainable: 18% of all human-produced greenhouse gas emissions result from meat production and 30% of the land surface of the planet is used directly or indirectly for livestock. As the world's population grows and becomes increasingly affluent, demand for meat will increase. Rainforest will disappear and fish stocks will fall.
Cows are major global-warming culprits. They digest food by enteric fermentation. To put it bluntly, they fart and burp more methane than any other mammal on the planet. Methane has a global warming potential 25-times higher than carbon dioxide. Horses do not digest in this way, and neither do pigs or chickens.
Unlike most pigs, chickens and some cows, horses are usually free range. They are also free from the health problems that occur when animals are bred for maximum muscle. When cows look like the Belgian Blue, you know that something has gone wrong.
Looking at this supercow, I don't feel so uncomfortable about the thought of eating horse or other animals for that matter. Scientists in Australia are advocating kangaroo as a greener alternative to beef. Insects are a delicacy in many parts of the world, and can be produced incredibly efficiently. Ten kilograms of feed can be converted to 1kg of beef, 3kg of pork, 5kg of chicken or 9kg of locust. Vegetable protein is even more resource efficient, and while we don't all have the necessary willpower, eating less meat is very planet-friendly. Alternative diets can also bring health benefits. Horse is a good source of omega 3 and iron, while insects are very low in saturated fat.
How can people be persuaded to alter their diets for the sake of health and sustainability? The answer is grounded in psychology. People make dietary decisions for a myriad of reasons, which are rarely as rational as we assume. Much can be learned from the vegetarianism movement which has grown in the UK from negligible levels to approximately 2 million people today. I suspect that even greater success can be achieved by emulating the techniques of the world's greatest marketers. Melinda Gates argues that we should look to Coca-Cola for answers. The company has used the power of positive, aspirational branding to achieve staggering success: 1.7bn servings of Coke a day.
The reason we need sustainability is to avoid negative outcomes, but the lesson from Coke is that consumer behaviour can be better affected by positive messages. This is the idea behind the UK Dream, which is working to rebrand sustainability as inspirational and aspirational.
The meat industry is operating near capacity. As the global population increases towards 9 billion, meat will become more expensive. We will have to learn to eat less protein or extract it from alternative sources. Don't be surprised if in a generation's time we're all enjoying regular meat-free meals, tucking into horseburgers and stir-frying locusts. And it will be a good thing, too.
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This article was amended on 28 March 2013 to change the percentage of human-produced greenhouse gas emissions from 19% to 18%, the number of vegetarians from 3m to 2m, the servings of Coke from 1.5bn to 1.7bn and to add that '30% of the land surface of the planet is used directly or indirectly for livestock'.