In December talks in Paris involving more than 200 countries may result in a new agreement aimed at reducing carbon emissions. In the months leading up to the conference, The Economist will be publishing guest columns by experts on the economic issues involved. Here, Vincent Réquillart of Toulouse School of Economics and the Institut National de la Recherche Agronomique argues that an initial focus on setting clear principles for fair cost-sharing will clear the way to a broader climate deal.
THE food chain, from farm to table, is responsible for roughly 30% of greenhouse gases (GHG) in France, ie slightly more than the emissions from the transport sector. More than half of these emissions are related to agricultural production, most of which is methane from animal husbandry and nitrous oxide from soil fertilisation. The rest of the emissions come from processing, distribution and customers' journeys to shops. Considerably reducing these emissions all the way along the chain is an important challenge that will take more than just improving the efficiency of the production chain.
Several NGOs are campaigning for a radical change in our eating habits, especially by drastically reducing our consumption of meat; 10 times more GHGs are emitted for a kilo of meat than for a kilo of fruit or vegetables. Reducing the meat in our diets is also important in terms of health. Diets in Western countries contain far too many animal products, particularly meat, too few plant products and too much fat and sugar. This drastic change to our eating habits would seem to reconcile the health and environmental issues linked tour diet.
Sadly, things are not so simple: "nutritionally healthy" diets have a similar or even worse impact on the environment than "nutritionally unhealthy" diets when you measure their greenhouse gas emissions. These "healthy" diets include far more fruits and vegetables, fewer sugary products, a relatively similar amount of meat and, ultimately, a greater quantity of less calorie-dense food. While the ratio of GHG emissions between a kilo of meat and a kilo of fruit and vegetables is 10:1, it is only 2:1 between 100 calories of meat and 100 calories of fruit and vegetables. So following nutritional recommendations doesn't necessarily mean a better environmental impact. The same goes for eating locally. Everything depends on the production conditions. If you live in Brittany, eating a tomato from Morocco emits less GHGs than eating a tomato grown locally in a greenhouse!
However, there are certain diets that balance health and environment. These diets comprise slightly fewer fatty/sugary products, a bit less meat and a few more plant products. They also correspond to a slightly lower calorie intake. Choosing this type of diet would decrease emissions by an average of 20%. That's going in the right direction, but we are still far from the global targets for reducing greenhouse gas emissions in Western countries (a 75% reduction by 2050).
How can we do more for the environment? Neither awareness campaigns nor taxes seem to be able to radically change our dietary habits. In other words, economic research indicates that even a significant increase in the price of meat relative to the price of plant products would not cause a strong swing away from buying meat in favour of buying plant products. This reflects the difficulty in significantly modifying dietary habits. Our diet is part of who we are, so any changes can only be gradual. Anyone who has travelled abroad has surely felt the irresistible craving for their favourite foods from home! For example, the "five-a-day" campaign only increased the consumption of fruit and vegetables by 5%.
The best solution is not to try and provoke a substantial shift from one food group to another, but to go for less radical changes, by favouring the healthiest and least environmentally harmful ingredients within the same food group. For example, in the meat group, replacing red meat with white meat would improve our diets in both nutritional and environmental terms. All it would take is a tax on GHG emissions, as recommended by most economists. Simulations indicate that diets would adapt accordingly, both in terms of the environment and health, provided the tax were high enough (at least €100 per tonne of CO2).
The reduction of GHG emissions linked to our food would therefore result from a series of adjustments rather than a single drastic change to our diet. Carbon pricing policies can help to progressively change our eating habits, but the policies that affect food still need to be consistent with each other. This is far from being the case, given that the Common Agricultural Policy was designed with neither health nor climate issues in mind.
