How eating less meat could help prevent extinction, climate change, cancer and the next pandemic

 

Grantham Lecturer in Global Change Ecology, Dr Kris Murray, explains why, from farm to fork, less is more when it comes to meat.

I’m not a vegetarian, and I’m unlikely to become one any time soon. I like making sausages and barbequing ribs, I love prosciutto crudo and lamb kebabs, and I’m a total sucker for a bit of bacon in my lettuce and tomato sandwiches.

But it has long been recognised that animal-based meat production is one of the major global environmental challenges of our time.

Livestock production for filling our tummies is truly immense: there are now around 3.5 poultry and 0.5 ‘common production’ mammals (cattle, sheep and pigs – red meat) raised per year for every one of us, now over 7 billion people. And that could double by 2050.

Meeting this demand needs, first and foremost, a lot of space. Consider the earth’s land surface – 45% of it is used to raise, graze or feed livestock. This has had huge impacts on natural ecosystems – from degradation to complete removal – with major consequences for biodiversity, including species extinction.

Meat and greenhouse gas emissions

But it’s not just space we need, it’s suitable land. Making land suitable for livestock leads to land-use change, including deforestation. In addition to crowding out biodiversity, this emits greenhouse gases (GHGs). Add in the other livestock-related GHG emissions (including nearly all of the methane, a very potent GHG) and something like 18% of total GHG emissions can be attributed to livestock.

But we’ve still got to eat, right? Is it really that much more destructive to eat meat compared to veggies? After all, they still require lots of land, and isn’t meat the more efficient source of protein in our diets?

No and no. This review from the Netherlands Environmental Assessment Agency found that the footprints of the most environmentally-friendly protein sources (mostly vegetable-based, particularly pulses) can be up to 190 (climate) and 525 (land-use) times smaller than the most unfriendly protein sources (mostly animal based, particularly beef and lamb) (see chart below).

This environmental toll is more than enough to persuade me to keep a lid on my own meat consumption, particularly red meat.

Meat and health: on the menu at ISEE2016

But if the doom and gloom of this negative environmental messaging isn’t the type of thing that motivates you (and research shows it probably isn’t), then consider the added detrimental effects on your personal health of overindulging on meat, a topic addressed by researchers at a huge gathering in Rome this month.

The occasion? A special session on “Climate change, mitigation measures and co-benefits” at the International Conference of the International Society of Environmental Epidemiology (ISEE), the largest meeting of its kind in the world.

Pauline Scheelbeek from the London School of Hygiene and Tropical Medicine showed that people on a low-meat diet have a 34% lower risk of dying from cancer, circulatory disease, and respiratory disease compared to high-intake meat eaters.

I reviewed the evidence for infectious diseases, showing how food-borne infections that result in hospitalisation or death, such as Campylobacter, Clostridium, Listeria and Salmonella spp., are more often associated with animal-based foods (particularly poultry) than vegetable-based foods.

I also pointed out that the emergence of completely new infectious diseases are often food-borne (ie transmitted through food contaminated by bacteria, viruses or parasites). They are also much more likely to be associated with animals (zoonotic), and most often related to changes in land-use (e.g., deforestation) and agricultural system changes (e.g., intensification). In addition, antimicrobial resistance (AMR) is being promoted by the widespread and growing use of antibiotics in animal production systems, with worrying signs that this could lead to an untreatable ‘superbug’– a danger that continues to make headlines around the world.

Win-wins for health and the planet

These findings contribute to a growing body of evidence illustrating significant health co-benefits associated with a range of climate change mitigation actions. These include everything from eliminating coal from our energy mix, to reducing air pollution from energy production and transport, to transitioning away from dangerous occupations (e.g., moving from coal mining into ‘green jobs’, which are in comparison much safer).

It’s a big idea on a global scale – that the costs of mitigating climate change could be partially or fully offset by the benefits it delivers in other sectors, in this case health. Factoring in these co-benefits provide policy makers with additional social and economic arguments and evidence to facilitate more rapid and progressive actions to limit climate change.

Eat green

The conclusion?

Reducing our meat production and consumption could help mitigate a range of chronic and infectious disease risks. At the same time, reducing meat consumption in high income countries from 1.75kg per week (the Food and Agriculture Organization (FAO) forecast) to 450g per week (the WHO recommendation) in 2050 would avoid almost 20 Gigatonnes of carbon dioxide per year.

Whether you’re more concerned about the environment or your own health, the benefits of eating green quickly stack up.

Great. But are diets that conform to global health guidelines entirely sustainable, or do we need to go even further to prevent biodiversity loss?  Can I still make a batch of sausages to get me through the summer barbeque season (according to WHO guidelines I’m allowed about 4 sausages a week)? The jury on that question is still out and a lot more work is needed, but it’s almost certainly a step in the right direction.