Does what we eat affect climate change?

Does what we eat affect climate change?

The simple answer is yes! Our diets definitely do have a major impact on the environment and here is why.

Emissions from agriculture account for 8% of total CO2 emissions in the UK, which may not sound like a great deal, however, most of the emissions from this sector are non–CO2 emissions. Nitrous oxides (N2O) and methane (CH4) account for the majority of agricultural emissions. Nitrous oxides are released from fertilisers used on agricultural soils and methane is produced by burping cows and sheep and manure. Methane and nitrous oxides are actually more harmful to the environment than CO2, since they are both more efficient at trapping heat in the atmosphere.

Global food production uses a third of the land surface area on the planet, which increases to a half if you only take into account the land capable of producing biomass. Moreover, 78% of agricultural land is used for the production of livestock, either directly for grazing or indirectly for growing feedstock for animals. This may not sound like a problem, but some of this land has been converted from forests. Deforestation has major environmental impacts since trees absorb carbon dioxide that would otherwise be released into the atmosphere. The UN estimates that 70% of deforestation in the Amazon is due to clearing land for grazing cattle and feed crop.

The other issue with land use is that we grow food that humans could eat and feed it to cattle, to fatten them more quickly for our own consumption. The problem with this is that the end product (meat) can feed less people than the plant based product fed to the animals. It has been estimated that 1 hectare of land can produce potatoes for 20 people per annum, or that same area will produce enough beef for 1 or 2 people. On top of the extra land needed, producing meat requires a lot more water. A staggering 15,000 litres are needed for every kilogram of beef steak while less than 2,000 litres are required for a kilogram of wheat.

What about energy related to food production? The Institute of Mechanical Engineers (IMechE) have estimated that it takes over 10 times the energy to create 1 calorie of meat compared to 1 calorie of edible plant matter. So our traditional square meaty meals are far more energy intensive than an equivalent plant-based meal. Already armed with a few basic facts we can see that a meat-based diet requires much more energy, land, and water resources than a vegetarian diet.

On top of these negative environmental impacts, a further issue is the amount of food we waste. It is estimated in a recent report by IMechE that 30-50% of all food is wasted before reaching our plates. If we reduced this waste, we could significantly reduce the environmental impact of our food.

Why should we care? Our population is growing rapidly, developing countries are eating more and more meat, and intensive farming is reaching its limits. So the question arises, how are we going to feed the world in the future? Research by the World Society for the Protection of Animals (WSPA) suggests that in order to feed everyone sustainably by 2050 we need to reduce our meat consumption. We don’t all have to be vegetarian; being meat free for one day per week will help dramatically. Researchers at Vrije Universiteit have estimated that eating vegetarian meals for just one day a week can save 13MT of CO2 per year. So next time you are tucking into that Sunday roast, spare a thought for the impact your meal has had on the environment.


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Philippa Hardy 

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