There is a link between the climate crisis and what’s on our plates. The hard facts are astounding, as is the difference a plant-based change can make.
Greenhouse gas (GHG) emissions are contributing significantly to global warming and climate change. The Intergovernmental Panel on Climate Change (IPCC) has warned us about the dire consequences of the projected global warming of 1.5°C above pre-industrial levels, which could happen in the next decade. This includes extreme heat, increased and more frequent flooding and droughts, rising sea levels, species loss and extinction, and risks to human health, livelihoods, food security, water supply, and economic growth.
The IPCC report released in 2021 states that it is “unequivocal” that human activity has warmed the atmosphere, the ocean, and the land on a scale that is “unprecedented” over thousands of years. Already, human-induced climate change is resulting in many weather and climate extremes in every region across the globe. Many changes due to GHG emissions are already “irreversible” for centuries to millennia. GHG concentrations have continued to increase and are “attributed largely to human activities, mostly fossil fuel use, land use change, and agriculture”. Urgent action is needed. The goal of the Paris Agreement is to prevent this catastrophic rise in temperature, yet, in 2020, scientists warned that without a drastic change to our food system, we will not be able to keep within these temperature limits and that dietary change is the most important approach to meeting these climate-change targets.
Dietary change is the most important approach to meeting [our global] climate-change targets
THE EMISSIONS ON OUR PLATES
Half of the world’s habitable land is used for agriculture, with more than 80 percent of farmland globally used for meat and dairy farming, be it for grazing animals or growing food for animals. Even though estimates vary, the food system is responsible for over a quarter, if not a third, of the world’s GHG emissions, and the production and consumption of meat, dairy, and eggs accounts for more than 60 percent of these emissions.
A more recent paper presented the results of a Global Sensitivity Analysis and suggested that animal agriculture is in fact responsible for a whopping 87 percent of GHG emissions. Even the most sustainably produced animal foods generate more GHG emissions than any plant foods, regardless of the distance travelled to get to your plate. The emissions from animal agriculture are greater than those from all forms of transportation combined.
It is not just the carbon emissions from animal agriculture that are problematic but also the methane produced by wetland rice systems and ruminant animals, and nitrous oxide from fertiliser and manure. Methane is an even more potent GHG than carbon, by 25 times, trapping the sun’s heat and warming the Earth 86 times as much as the same mass of carbon dioxide over a 20-year period. Within animal farming, methane is generated from the burps of ruminant animals – principally, cows and sheep – and global emissions continue to rise dramatically, in part due to animal agriculture and farming. Raising ruminant animals for meat and dairy alone accounts for around half the GHG emissions from animal agriculture.
Some argue that because methane is relatively short-lived in the atmosphere – only 10 years compared with hundreds of years for carbon dioxide – it matters less. This does not mean we should continue producing methane. It means we have a chance in a shorter period to significantly reduce these emissions. In fact, it seems we have been vastly underestimating the contribution of methane from intensively raised animals to GHG emissions by as much as 90 percent, despite the prevailing narrative that factory farms use less land and are a more ‘efficient’ way to raise animals for food.
The United Nations is clear: we have to address methane emissions now in order to keep global warming below levels associated with irreversible and catastrophic consequences.
THE POLLUTION IN PRODUCTION
Nitrogen emissions from animal farming are also increasingly problematic. These emissions come from nitrogen present in synthetic and organic fertilisers and animal manure and urine, resulting in nitrous oxide generation, another potent GHG gas. Nitrous oxide is 300 times more potent than carbon dioxide, trapping more heat and remaining in the atmosphere for longer than methane – over 100 years. Animal agriculture contributes around a third of nitrogen emissions, with most of that coming from the production of animal feed.
The vast quantities of animal manure produced from farming not only emit nitrous oxide but also contaminate land and pollute our water systems. The safe management and disposal of this manure are becoming impossible tasks. The waste from animal farming is contributing to air pollution from gases such as ammonia, hydrogen sulphide, nitrous oxide, and methane. These gases have an adverse impact on human health, with farm workers and people living close to animal farming operations having an increased risk of asthma and other lung problems and cardiovascular diseases.
A first-of-a-kind study from the US determined how the production of various foods impacted air quality and consequent health outcomes. The study showed that 17,900 deaths a year were attributable to air pollution caused by agriculture, with ammonia emissions, farm animal waste, and fertiliser application accounting for most of these deaths. Altogether, 80 percent of these deaths were attributed to the production of animal-derived foods, with red meat the greatest contributor. The production of all plant foods considered was less polluting than any animal foods. The authors concluded that a shift to vegetarian and vegan diets would vastly improve air-quality-related health issues.
THE PLANT-BASED DIFFERENCE
There is a vast inefficiency in the current food system when you consider that animal farming produces only 18 percent of the calories and 37 percent of the protein consumed globally while using over 80 percent of farmland.
Farmed animals themselves also consume more calories and protein than they produce for human consumption. Conservative estimates show that farmed animals consume between six and 12.5 kilograms of plant protein to produce a single kilogram of animal protein. This means that we currently produce enough food to feed two planets. If we were all to transition to eating a meat- rich diet typical of the 20 most industrialised countries, we would need seven planets to produce enough food!
If we all adopted a 100 percent plant-based or vegan diet, we could reduce the land used for food production by 76 percent and GHG emissions from the food system by up to 50 percent. The land released would then be able to be used to capture significant amounts of carbon. Crops can also be produced in a manner which allows for carbon sequestration into the soil instead of contributing to emissions, with further reductions in fossil fuel use also possible.
Further studies have examined the impact of shifting towards plant-based diets on both human and environmental health and concluded definitively that it would provide combined benefits. Plant-based diets could reduce GHG emissions by 56 percent and other environmental impacts of the food system by six to 22 percent. At the same time, this improves the nutritional quality of our diet, significantly reducing the burden of chronic disease and reducing premature mortality by 22 percent. When considering protein sources, tofu, beans, nuts, and peas have the lowest carbon footprint compared with any source of animal protein, and their consumption has significant advantages for human health.
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This article is an edited extract from Eating Plant-Based: Scientific answers to your nutrition questions by Dr Shireen Kassam and Dr Zahra Kassam. Published by Hammersmith Books. Available in Australia via Booktopia. |
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