The planet’s dangerous appetite for meat

Last year marked the centenary of the general theory of relativity, but it appears Albert Einstein also showed great foresight when he said, “Nothing will benefit human health and increase the chances for survival of life on Earth as much as the evolution to a vegetarian diet.”

With the recent announcement by the World Health Organisation that processed meats are highly carcinogenic, and the success of last month's UN COP21 talks on climate change, it could be time to consider reducing meat consumption as a matter of both national and international policy.

In October, the World Health Organisation published a report outlining that processed and cured meats such as bacon and sausages are among some of the most carcinogenic products, although the risk of actually developing cancer from them is low. Red meats were also indicated as a probable cause of cancer. The report outlines that colorectal, stomach, pancreatic and prostate cancers can all be linked to diets high in these cured and processed meats.

It is also known that meat-rich diets might be a contributor to coronary heart disease, type II diabetes, and other conditions that reduce human life expectancy.

An article last year in the journal Nature, "Global diets link sustainability and human health", indicates that a fish-based diet reduces the risk of type II diabetes by 25 per cent, improving to 40 per cent for full-blown vegetarians. Pescetarians (fish eaters) and vegetarians also have a 10 per cent reduced risk of cancer compared with omnivores. The message is clear: processed and red meats increase our risk of life-threatening diseases.

At the same time, as a taste for meat grows in emerging nations, the relatively recent rapid development of the meat industry has become a major contributor to climate change.

The methane problem

What is often overlooked is that global food production is a greater greenhouse-gas contributor, and therefore threat to humanity, than all the world's transport combined. This is partly because meat, in particular beef production, generates huge amounts of methane via livestock emissions, and methane is a far more potent and dangerous greenhouse gas than carbon dioxide.

Global food production and agriculture account for about 25 per cent of all greenhouse-gas emissions. The clearing of areas for agricultural use reduces the vegetation that otherwise acts as a carbon sink (storage of carbon in the land rather than the atmosphere), and effectively increases carbon-dioxide levels. These land clearances also enact species extinction and are therefore considered a major environmental disaster.

The same study in Nature shows that pescetarians and vegetarians are responsible for significantly less greenhouse gas emissions than their omnivorous neighbours. This implies that in a hypothetical exclusively vegetarian world, greenhouse gas emissions from food production would be substantially reduced. A vegan diet is responsible for even less greenhouse-gas emission. The article states: "There are plausible solutions to the diet/environment/health trilemma, diets already chosen by many people that, if widely adopted, would offer global environmental and public health benefits."

According to lead author David Tilman of the department of ecology at the University of Minnesota, “We showed that the same dietary changes that can add about a decade to our lives can also prevent massive environmental damage.”

So the problem with meat is twofold, with negative implications for health, and for the climate and environment. This means that dietary change, specifically a move towards reduced-meat diets, is essential if governments intend to keep their populations healthy and global warming under the proposed safe limit of two degrees. A switch to reduced-meat diets appears to be a win-win situation, and in the long run would save governments massively on healthcare costs, and increase life expectancy.

Therefore, to protect populations from cancer, and also to reduce greenhouse-gas emissions in order to mitigate the effects of climate change, governments will need to develop initiatives to advertise the health benefits of a reduced-meat diet. Such initiatives might include taxation on meat products, as well as TV, radio and online awareness campaigns, perhaps even including new years’ resolutions.

Such dietary changes might become necessary if governments are to make any progress towards reducing cancer rates and the negative effects of global warming.

For this reason, reduced meat economies, with increased emphasis on vegetable-based diets, should be included in global health and climate-change discussions, alongside smoking and obesity. And we need divestment from fossil fuels and investment in renewable energies.

• Dr Conor Purcell is a postdoctoral researcher at Prof Jennifer McElwain's programme for experimental atmospheres and climate at University College Dublin. He specialises in future climate change prediction

MEAT PRODUCTION: BIG ENVIRONMENTAL BEEF

Over the past 50 years the global meat industry has experienced massive increases in production. Between 1963 and 2014, meat production rose from 78 million tons to more than 300 million tons – a fourfold increase.

Major causes are the growing markets for meat, particularly in Asia, where population expansion into urban centres has promoted the development of the meat industry on large scales. That’s not to say that meat production hasn’t risen in western nations too.

Most people are unaware that food production and agriculture contribute to an estimated 25 per cent of greenhouse-gas emissions, with a large part of this from meat production itself. Fifteen per cent of greenhouse gases are attributed to the global meat industry, and land use for livestock grazing amounts to more than 25 per cent of the Earth’s ice-free surface.

In particular, beef production is the main cause of these gas emissions – methane in this case, which is emitted by cows.

This all means that our increasing appetite for meat is contributing enormously to global warming, and the problems associated with a changing climate. Last month’s UN COP21 conference on climate change in Paris agreed on a united deal to reduce reliance on fossil fuels and to invest in renewable energies.

It appears any significant step forward would include an action plan to reduce meat consumption and production.