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What we eat plays a critical role in shaping our planet’s future, and certain dietary choices leave a much larger carbon footprint than others. By choosing more sustainable plant-based foods we can significantly lower our footprint and contribute to the fight against climate change.

Climate change is accelerating, driving extreme weather events, biodiversity loss, environmental degradation and food insecurity. According to the World Meteorological Organization, every key climate indicator reached record levels in 2024. It was the warmest year in the 175-year observational record, with global temperatures climbing to 1.55°C (margin of uncertainty ± 0.13 °C) above pre-industrial levels, making it likely the first year on record, where temperatures exceeded the 1.5°C long-term global temperature goal set by Paris Agreement on climate change. Greenhouse gas (GHG) concentrations hit record highs in 2023, with real-time data confirming that emissions continued to rise in 2024.

The global food system is a key contributor to global GHG emissions and climate change. While different foods contribute to climate change at varying levels, our food choices are key in shaping our carbon and environmental footprint. This article examines the link between diet and climate change, highlighting why adopting a whole food plant-based diet is a powerful solution for reducing our environmental impact and supporting a healthier planet.

The link between diet and climate change

Food systems and GHG emissions

Studies[1,2] indicate that the global food system is responsible for approximately one-quarter to one-third of human-induced GHG emissions. Emissions come from multiple sources, such as land use (including deforestation), agricultural production, processing, transportation, packaging, post-retail cooking, and food waste.

Industrial animal agriculture is one of the most significant contributors, as it requires vast amounts of land (~45-50% of our planet is agricultural land and ~80% of that is used for livestock), water, and feed while producing significant methane emissions (a GHG with a warming potential 28-36 times that of CO₂) from enteric fermentation in ruminant animals. The widely cited estimate of 14.5% of livestock’s contribution to global greenhouse gas (GHG) emissions is from the UN Food and Agriculture Organization (FAO). However, this figure is from data that is nearly 17 years old and has been contested, with more recent estimates ranging from 12% to 20% of global emissions. Furthermore, a recent report suggests that animal agriculture is the single largest driver of climate change, surpassing all other human activities. Another report supports these findings, calling for increased transparency in GHG accounting conventions to reflect the true impact of animal agriculture on the climate.

Closer to home, New Zealand’s Ministry for the Environment reports that almost 50% of New Zealand’s GHG emissions come from agriculture – 75% of which comes from methane emissions from livestock. The next largest source is nitrous oxide from nitrogen added to soils and from manure management. According to the Climate Council, in Australia agriculture accounts for approximately 18% of GHG emissions (higher than the global average of 11.7%) with their emissions dominated by energy production at ~55% and transport at ~21%. In 2022-23, agriculture was responsible for over half of the country’s methane emissions – with 65% of these emissions coming from cattle.

A study of New Zealand’s food system, showing no notable deviation from global trends, showed that not only were whole plant foods substantially less climate polluting than animal-based foods but that adopting plant-focused dietary patterns would also confer large health gains and cost savings for the healthcare system.

These and other studies have consistently shown that diets rich in animal products, particularly meat, are associated with significantly higher greenhouse gas (GHG) emissions compared to plant-based diets. A recent UK analysis showed that vegan diets generate 75% less GHG emissions, use 75% less land, require 54% less water, and have a 65% lower impact on environmental biodiversity than meat-heavy diets.

Agricultural production may be the single largest contributor to GHG emissions, however land use changes, such as deforestation often driven by the expansion of farmland for livestock and feed crops, result in the loss of critical carbon sinks. Forests and wetlands naturally sequester carbon, helping to mitigate climate change, whereas deforestation and clearing results in ever larger amounts of carbon dioxide (and methane) being released into the atmosphere both from the process itself and from the decline in carbon storage.

Water and land use

Global scarcity of water and land, driven by human activity, results in a lack of availability of these natural resources relative to human demand – especially with an ever-increasing population.

Globally, over 70% of fresh water and, as mentioned, almost half of the world’s habitable land are used for agriculture. Livestock occupy nearly 80% of this land yet produce only 17% of the world’s calories and 38% of its protein, making it a highly inefficient food source. In contrast, crops grown directly for human consumption supply the majority of global calories and protein (83% and 62%, respectively), using just the remaining ~20% of available agricultural land.

The following charts[1] demonstrate that land and fresh water requirements for producing various protein sources differ significantly, reflecting the impact of animal-based versus plant-based foods.

The chart below[1] shows direct impact comparisons between dairy milk and other plant-based milk. Dairy milk has significantly higher impacts than the plant-based alternatives across all metrics. Aside from using ten times as much land, and 22 times as much freshwater per litre of milk, it also causes around three times as many greenhouse gas emissions and creates much higher levels of ecosystem pollution

Impact on rivers, lakes and oceans

In addition to the extensive withdrawal of freshwater from rivers, lakes, and other sources, the global food system is a major contributor to ecosystem pollution, contaminating freshwater bodies and oceans.

Our food system relies heavily on synthetic fertilisers to grow sufficient food crops for human consumption and livestock feed. According to the FAO, global fertiliser consumption increased from around 30 million tonnes in the 1960s to close to 200 million tonnes in 2019. Large-scale industrial farming often relies on monocultures—growing the same crop repeatedly on the same land—which depletes soil nutrients, reduces biodiversity, and makes crops more vulnerable to pests and diseases. This leads to more reliance on synthetic fertilisers, pesticides, and herbicides, which can degrade soil health, contaminate water sources, and disrupt ecosystems. Livestock feed crop production is a significant driver of monoculture farming.

In a process known as eutrophication, primarily nitrogen and phosphorus from excessive fertiliser use, and excess nutrients from animal waste in intensive animal agriculture settings, run off farmland into groundwater and rivers. This nutrient pollution from agricultural sources is estimated to account for around 78% of global eutrophication[1]- impacting drinking water quality, degrading habitats, disrupting breeding grounds for various species, and producing algal blooms that are incredibly harmful to freshwater and marine ecosystems. This overgrowth from specific algae species produces toxins that can harm marine mammals, birds and humans. The algae blooms also clog fish gills and cause hypoxic (low-oxygen) waters in ocean environments (known as dead zones).

While industrial plant-based agriculture can still contribute to water pollution and eutrophication (primarily through monocultures and pesticide use), sustainable plant-based farming methods, such as organic and regenerative agriculture, use fewer synthetic inputs and produce far less concentrated waste, reducing nutrient pollution.

The world’s oceans significantly mitigate global warming by absorbing 25% of global carbon dioxide emissions and capturing 90% of the excess heat from these emissions. Feeding our burgeoning global population and the resultant increase in greenhouse gases means that oceans are increasingly absorbing more CO₂ from the atmosphere. This causes ocean acidification, which reduces the ocean’s ability to sequester carbon. And as the absorption of excess heat continues, ocean temperature and sea-level rise cause a significant impact on marine biodiversity, weather patterns and marine ecosystems. The threat to human life, livelihoods and displacement is all too real, with sea-level rise doubling during the last three decades.

Shifting to a predominantly plant-based diet could significantly reduce oceanic dead zones—helping to restore marine ecosystems and mitigate climate change. This is not just an environmental necessity but a crucial step in building a food system that can sustainably nourish future generations while protecting our oceans.

Biodiversity loss

Since the beginning of the first agricultural revolution 10,000 years ago, demand for land has seen the demise of one-third of the world’s forests, many wetlands and other wildlife habitats, causing wildlife populations to decline significantly. Although agriculture supports crops grown for human consumption, intensive animal agriculture is a key driver of this biodiversity loss; with nearly 80% of the world’s agricultural land used to raise livestock for meat and dairy, an estimated 36% of global cropland produces feed for these animals. It is alarming to know that, excluding humans, 94% of the worldwide mammal biomass is livestock (equaling 15 livestock for each wild mammal), and 71% of bird biomass is poultry livestock[1].

To grow the crops needed to sustain such massive numbers of livestock (estimated globally to be 31 billion land animals at any one time), farmers typically elect to use monoculture methods, as mentioned earlier, to gain maximum yield. Growing one crop species over a large land area diminishes plant diversity, affecting food sources and habitats for many animals, including pollinators, which has a knock-on effect on the entire ecosystem. A loss of natural habitats and the use of pesticides has also contributed to a global trend of insect population decline. With one-third of global food crop production relying on pollinators to some extent, food security is of major concern.

Nowhere in the world is biodiversity loss felt more keenly than in Australia, where large-scale deforestation (an area equivalent to the MCG is destroyed every 86 seconds) is pushing some Australian animals to the brink of extinction. According to the Wilderness Society, Australia now holds the number one ranking for mammal extinctions worldwide and is second only to Indonesia for biodiversity loss – 67 wildlife species and 37 plant species have gone extinct. One of the main reasons that hundreds of thousands of hectares of Australia’s forests and bushland are destroyed every year is for agricultural expansion (to create pasture to raise cattle for beef) – with land clearing in Queensland leading the bill.

Human activity is also causing biodiversity loss in our oceans, resulting in significant declines in marine species due to overfishing, habitat degradation and destruction, pollution, and climate change.

Energy efficiency

Animal agriculture is an inefficient way to convert plant-based resources into edible human food. It requires vast amounts of crops to be grown specifically for animal feed, diverting resources that could be used to nourish human populations directly. As we have mentioned, around 36% of global crop calories are used to feed livestock, yet animals only convert a fraction of these calories into edible meat products. If these crops were grown directly for human consumption, far fewer resources would be needed to feed the same number of people.

The following graph[3] shows the energy (in)efficiency of meat and dairy production :

Animal agriculture also highly depends on fossil fuels, from feed crop cultivation and livestock management to processing and transportation. Removing livestock from the equation significantly reduces fossil fuel consumption, making plant-based agriculture a far more energy-efficient alternative. Transitioning to a plant-based food system could drastically lower resource demands, leading to a more sustainable and resilient food supply.

The importance of shifting dietary patterns

The global food system is at a crossroads, with industrial animal agriculture putting immense strain on the planet’s resources. Producing meat, dairy, and eggs requires vast amounts of land, water, and fossil fuels while contributing significantly to greenhouse gas emissions. Animal agriculture also drives deforestation, soil degradation, and water pollution, with vast areas of land cleared to grow feed crops instead of directly nourishing people. Shifting toward a predominantly plant-based food system could free up vast areas of global farmland, allowing for ecosystem restoration, reforestation, and carbon sequestration—key actions in the fight against climate change.

With the global population predicted to rise to 10 billion by 2050, maintaining our current food system will only exacerbate resource scarcity and environmental destruction. A transition to plant-based diets would improve food security and reduce the public health risks associated with industrial livestock farming, including antibiotic resistance and zoonotic disease outbreaks. By prioritising plant-based agriculture, we can create a more sustainable, ethical food system that nourishes future generations without depleting the planet.

Practical tips for reducing diet-related emissions

Now that you understand the impact of our food choices on the climate, you’ll see how shifting to a more plant-forward diet can significantly reduce your carbon footprint. Here are some practical tips to help you make that positive change:

• Incorporate more plant-based meals – start small by incorporating just one plant-based meal per week. Need ideas? Explore our recipe collection for inspiration.
• Choose plant-based proteins – swap meat and dairy for nutritious alternatives like lentils, beans, chickpeas and tofu. Download our simple swaps guide for some great plant-based substitutes.
• Reduce or eliminate dairy – opt for plant-based milk, yoghurt and cheese to drastically cut land and water use while eliminating methane emissions.
• Be mindful of processed foods – many processed foods require more energy to produce and may contain hidden animal products like milk powder. Cooking from scratch helps reduce reliance on these products while supporting a healthier diet.
• Grow your own food (if possible) – grow fruits and vegetables to develop a deeper appreciation of food sources and sustainability. Choosing produce that doesn’t rely on synthetic fertilisers and pesticides benefits your health and the planet.
• Minimise food waste – plan meals and store food properly to reduce waste. Less waste means fewer resources are used in food production, and fewer methane emissions are produced by landfill decomposition.
• Download our Going Plant Based or Eat Your Way to Better Health guides for expert tips and practical advice.
• Take our FREE interactive online dietary assessment – the 4Leaf Survey to estimate the percentage of your calories coming from whole plant sources and obtain your diet ‘climate score’.
• Sign up for one of our online courses:
  – Jump right in with the DFN Health Challenge or
  – Take it step by step and Make the Switch to whole food plant-based eating.

Like all energy systems, food production requires inputs and generates outputs that impact the environment. We can work towards a more sustainable future by rethinking our food choices—one meal at a time.