Vegetarianism:Imagine all the billions of animals living on the surface of this planet. Imagine their combined volume. Now divide that mass of flesh by five. That is the amount of animal bulk that human beings rear for meat and dairy. In other words, 20 per cent of the world's terrestrial flesh and blood is there to service our eating habits.
Such a statistic makes it easier to understand how livestock farming can adversely affect earth's wellbeing. According to the United Nations Food and Agriculture Organization, 9 per cent of all human-related carbon dioxide comes from farm animals. More damaging is the 37 per cent of methane, a greenhouse gas that is 23 times more powerful than carbon dioxide. Add to this the 65 per cent of nitrous oxide (296 times more warming than carbon dioxide) and the 64 per cent of all human-associated ammonia (which promotes acid rain) and we can see that our carnivorous tendencies are adding significantly to climate change.
A study by the National Institute of Livestock and Grassland Science in Tsukuba, Japan, shows that a kilo of industrially farmed beef produces greenhouse gas emissions with a warming potential equivalent to 36.4kg of carbon dioxide. And that, apparently, is the amount of carbon dioxide an average European car emits when driven for 250km. Clearly, in a fair world, only vegetarians should be allowed to drive. That same kilo of beef, by the way, consumes 169 megajoules of energy, enough to power a 100w bulb for more than two weeks - so it's lights off and early to bed for the foreseeable future if you've just eaten a steak.
Seriously, though, amending our diet to a less meat-heavy menu could have a hugely positive effect on the health of our planet (not to mention our own physical condition). Besides the fact that livestock farming guzzles energy and emits copious greenhouse gases, it also hogs land: 30 per cent of earth's terrain is used for pasture or growing feed. Other effects of raising vast herds of animals for our plates and burger buns include desertification, erosion, deforestation and eutrophication and pollution of water. (Eutrophication is the build-up of excess minerals.)
I'm talking about this now because next Monday is World Vegetarian Day - the perfect time to consider adding more vegetables to our meals and subtracting some of the meat. The Vegetarian Society of Ireland (www.vegetarian.ie) celebrates the occasion next Saturday with a vegetarian fair at Cultivate, in Temple Bar, Dublin, and will have plenty of ideas on how to save the planet while eating your greens.