Authors: Simon Hill & Katherine Annesi
Simon Hill requires little introduction as he is well-known as a leading plant-based educator. Alongside his growing social media community, he is the host of the Plant Proof podcast, inspiring countless people and educating on the nutritional benefits of adopting a plant-based diet. His guests are highly respectable in their own rights. Together with co-author Katherine Annesi of the University of Sydney, Simon takes food-related education to the next level by addressing the critical environmental topic investigating how the food system affects climate change. This investigation breaks down six key questions that the research speaks for, concluding that the diet that is best for your health is the same diet that is good for planetary health.
Despite decades of international conferences, energy efficiency initiatives, growing investments in the renewable energy sector and a budding global awareness of climate change, anthropogenic emissions and concentrations of carbon dioxide have risen steadily over the past decades. Since 1990, emissions have almost doubled , and current projections indicate this trend is unlikely to slow down in the foreseeable future. In fact, despite the diplomatic success of the 2015 Paris Agreement, rather than being on track for 1.5 degrees temperature rise as stipulated by the multilateral agreement, projections have identified that we are now heading towards a rise in global average temperatures of at least 3 degrees Celsius by 2100.  Beyond 2100, projections indicate we might be heading towards a 4-5° degrees C warming. 
While these small numbers may not appear to indicate anything catastrophic, scientists have estimated that a 3°C increase in average global temperatures could bring ‘outright chaos’ to our societies, sparking a global water crisis, inundating entire regions and provoking a widespread failure in our global food production.  Although we can’t know definitely, they have estimated that a warming of 4°C could result in a reduction of the human population by 80-90%, and past that, the temperature would simply become largely incompatible with human existence.  Clearly, a lot is at stake.
Unfortunately, despite the exciting possibilities emerging with renewable technologies, global investment and uptake in green technologies remains a small fraction of what is required to reduce global emissions. While this is an absolute priority and a necessary step to help mitigate climate change, even if we garnered the necessary political and financial will to invest in these technologies, such solutions will most likely take decades to implement – time which is simply running out.
The good news, however, is that beyond the energy industry, there are other sectors of our economies that could be decarbonised faster which could help us stay under a 3-4 degree scenario. One of these is the agriculture sector. In fact, agriculture is one of the key human activities that impacts our climate and ecosystems.  The cumulative emissions generated by agriculture, forestry and other land use accounts for 24% of global emissions,  and livestock alone is said to be directly responsible for 14.5% of global emissions each year. 
In Australia, agriculture is currently the fourth largest source of greenhouse gas emissions, responsible for 13% of total emissions,  but importantly, of these, two-thirds are the result of just grazing beef and sheep.  The situation is closely mirrored In the United States, where agriculture accounts for 9% of total emissions – which, although gigantic, pale in comparison to its other energy-intensive sectors  – of which livestock is responsible for 42%. 
Given that both per calorie and per gram of protein animal foods are significantly more resource-intensive than plant foods, [12-14] scholars have argued that the cheapest, easiest, fastest and most effective action that can be taken at a global scale to help mitigate climate change is a dietary shift towards consuming more plant-based foods and less meat. [15-18] If livestock’s contribution to environmental problems is a substantial one, the thinking goes, its potential contribution to their solution could be equally large. Furthermore, beyond affording environmental benefits, a reduction in meat consumption to a healthier intake level would also positively reduce the burden of disease associated with its overconsumption. 
Since its inception, Plant Proof has been primarily focused on nutrition – but what good is a healthy diet if we cannot survive on a world threatened by climate change? The point is that focussing entirely on the nutritional aspect of a diet without taking into account its environmental consequences will end up being rather pointless if our planet is uninhabitable. As such, in this article, my aim is to leave ethics, nutrition (for the most part) and my personal choices aside, and focus only on one question: according to the best available scientific data, what is the best diet that the world can adopt if we are going to help mitigate the existential threat posed by climate change?
TO ANSWER THIS, I SET OUT TO INVESTIGATE 6 QUESTIONS*:
- How does plant vs animal agriculture compared in environmental terms?
- Is methane a ‘myth’ as stated by Sarah Wilson?
- Is grass-fed that much better for the environment and can holistic grazing methods as those proposed by Allan Savoury really help mitigate climate change?
- So is the solution to cut back on red meat and replace it with other animals?
- Is Australia really exempt from all the damaging practices used abroad?
- What would happen if we all went vegan?
*Follow the links attached to find out the answers to these pressing questions.
The bottom line is that, beyond ethical considerations, current meat consumption is grossly unsustainable from both a health and environmental perspective. This is not about being a vegan or pushing a plant-based message – the simple, environmental truth is that we need to eat less meat and dairy – much less. Our challenge is clear: ahead of the population growth our planet is expected to be subjected to, we need to produce more food than ever before, but do so in a way that emits drastically fewer emissions than at present. Quite simply, in a world of almost 8 billion people with a finite amount of land and resources, current rates of meat consumption simply cannot be sustainably maintained. While meat may play a pivotal role in enabling those who live in impoverished societies to meet their nutritional requirements and sustain their livelihoods, its role is indeed limited in affluent nations which boast an abundance of dietary options. 
Yes – grazing livestock does have a place in a sustainable food system – but that place is extremely limited. Does this mean you should take up the occasional meat dish? Absolutely not – by sticking to plant foods you will effectively offset the environmental burden posed either by those who either refuse to reduce their consumption or those who require meat to meet their nutritional requirements in rural societies. But this also means that if family and friends aren’t quite ready to give up their favourite animal-based foods, you can let them know that even a modest reduction in the frequency of these foods can yield meaningful results.
At the end of the day, a well-planned plant-based diet is not only a great option in nutritional regards – but it can also yield meaningful benefits to our planetary health at a time in which climate change threatens to wreak havoc on our livelihoods. Indeed, the bottom line is that the diet that is good for you is good for the planet. 
This blog was co-written with Katherine Annesi from the Department of Sustainability at the University of Sydney and originally published on the Plant Proof website with links to all references. Head to @plant_proof and @plantd.co to join the conversation about climate change and our food system. Comment with your key takeaways and if you’re passionate about the environment, tag a friend in our posts to ensure that this message spreads far and wide.