Greenhouse gases, like carbon dioxide, methane, and nitrous oxide, are those which trap solar energy within the Earth’s atmosphere. In high volumes, these gases cause the planet to warm at an unnatural rate. This effect otherwise known as the greenhouse gas effect, or global warming.
Unfortunately, there is evidence to suggest that the volume of these gases in our Earth’s atmosphere has been rising, and continues to do so. Carbon dioxide has increased by over 40% in the last two centuries, methane levels today are thought to be more than twice those of pre-industrial times and nitrous oxide saw a 30% increase between the years 1980-2016.
As the science predicts, this rise in greenhouse gases has come parallel to a rise in global average temperature. In 1981 the average rate of increase was ~0.18°C (or 0.32°F). Today, the average rate of increase is more than twice that!
This gradual warming spells real trouble for life on Earth. A rising temperature brings with it a plethora of negative consequences: more frequent and more severe weather events, higher sea level and increased ocean acidity as well as higher wildlife extinction rates.
Now more than ever before, it is important that we do everything in our powers to stabilise the increasing global temperature. A huge task, for sure. But, with around 50-65% of all greenhouse gases being human-caused, or anthropogenic, there is a lot of scope for repair.
So how can we help to reduce the amount of greenhouse gases that are released into the atmosphere? Well, for a long time, the answer to this question was transport. The focus of our discussions around greenhouse-gas emission reduction centring around personal transport use: how many flights we take each year and how many miles our cars rack up.
While I don't disagree that we ought to be mindful of our transport use, there is a growing consensus that we should worry about the food on our plate at least as much as the petrol we burn in our cars. That’s right. I said, the food on our plate. Our three square meals a day: breakfast, lunch, and dinner (or “tea” depending on which part of the UK you are from).
Who would have thought, what we eat could be having as large an impact on the health of our planet as the number of trips we take to work each week. Now, don’t be alarmed. I’m not about to prescribe mass starvation in a bid save our planet. That would be Ludacris! No, there is evidence to suggest that when it comes to food, some products more than others, contribute disproportionally to global warming.
In a recent study published in Science, academics Poore and Nemecek considered the relative climate impact of a whole host of different foods. To do this, they weighed up all of the factors that go into producing food, including the land required for production, the farming process and the transportation. Their findings had one resounding conclusion: of all foods considered, animal-derived food products have the largest emissions footprint. Products like beef, lamb, cheese, pork and poultry dwarf that of root vegetables, citrus fruits, potatoes, nuts and pulses.
So, let me rephrase. We should worry about the meat, eggs, and dairy on our plate at least as much as the petrol we burn in our cars. So, how does the animal agriculture industry weigh in against the transport industry, in terms of volume of greenhouse gases produced?
Well, the livestock sector is said to be responsible for approximately 7.1 billion tons of greenhouse gas emissions each year, a figure which equates to around a 14.5% contribution of all anthropogenic greenhouse gas emissions. Less conservative estimates suggest that this figure might be as high as 18% or even 51%. Whichever figure you take, this contribution is either on par or greater than all emissions from the world’s vehicles, including cars, trains, airplanes and boats which contribute 7.0 billion tons of greenhouse gas emissions or 14% of all anthropogenic greenhouse gas emissions.
While the overall emissions contribution of the transport and the livestock sector are (at least) on par, there are a number of important differences between these two industries when it comes to climate change contribution.
Like the transport sector, the animal agriculture industry produces a great deal of carbon dioxide by burning fossil fuels, both in the production and transportation of livestock. But, unlike the transport sector, the animal agriculture industry releases carbon into the atmosphere by altering the landscape and clearing land either for pasture or for growing animal feed.
Today, it is estimated that half of all habitable land on Earth is being used to produce food, with around 77% dedicated specifically to animal-based agriculture. To acquire this land, the animal-agriculture industry has needed to alter the landscape: deforest the land and bulldoze through delicate habitats.
The production of animals and of crops for animal feed accounts for 80% of global deforestation. Deforestation has important implications for climate change. When trees are cut down, their stored carbon is released into the air as carbon dioxide. It is estimated that deforestation alone contributes up to 10% of the anthropogenic carbon dioxide emissions and is therefore a contribution that we must consider when discussing the impact that animal agriculture has on our climate.
Also unlike the transport sector, the animal agriculture industry produces a huge volume of methane and nitrous oxide emissions. These are gases that are directly produced by livestock themselves, by farting and pooping. The global population of cows produce an average of 150 billion gallons of methane each day, in flatulence alone. Globally, farmed animals produce a staggering 3.4 billion tones of poo every year!
Broken down by gas, it is estimated that the livestock sector produces 65% of all anthropogenic nitrous oxide emissions and 37% methane emission, making animal agriculture the leading source of both such gases across the globe.
But with carbon dioxide dominating conversations around global warming, how concerned should we be about these other two greenhouse gases? It seems that the answer is: “even more concerned”.
According to facts published by Cowspiracy, Methane – a powerful greenhouse gas, is said to be somewhere between 25-100 times more destructive than carbon dioxide and with a global warming potential 86 times it’s size! For nitrous oxide, the global warming potential, relative to that of carbon dioxide is a whopping 310 times greater.
And, aside from the obvious implications this has for our changing climate, this huge amount of waste that farmed animals create also spells trouble for our environment. While some of this waste treated and recycled as crop fertiliser, the majority is left untreated in hazardous cesspools. Animal waste contains high concentrations of nitrogen, antibiotics, ammonia, methane, and carbon dioxide. Not only is this a cause of the steady warming of the planet, but it is also a threat for the surrounding environment and those living in close proximity to farming plants.
So what can we do to help?
Well, the big take home here is that a reduction in our consumption of animal-derived food products is a sure fire why to contribute to a reduction in global greenhouse gas emissions and ultimately a slowing of our warming planet.
One study, has provided evidence to support such argument. In this study, the diets of 2,041 vegans, 15,751 vegetarians, 8,123 fish-eaters and 29,589 meat-eaters were assessed for their emissions contribution. It was found that a vegan diet produced half of the greenhouse gas emissions than a meat-based diet.
While total abstention from meat and other animal-products seems to offer us the best solution for tackling greenhouse gas emissions, reduction also seems promising. Did you know that just by cutting out one portion of beef per week, you could save 7.2kg CO₂eq? That’s enough to charge 927 smartphones, about equivalent to burning 3.1 liters of petrol or travelling 28.9 kilometers in a passenger vehicle. What's more, to absorb this volume of CO₂ you would need 17 trees. This is according to the figures published by The Meat Footprint Calculator, a free tool that you can use to calculate the impact of your own reduction.
Be it abstention, or reduction, each and every one of us can do our bit to reduce the production of greenhouse gases and slow the unnatural warming of our planet.