Michelle McCrackin

Michelle McCrackin

One person’s dietary decisions won’t have much effect 

A manure diet – in wait for reduced meat consumption

Reducing meat consumption can have positive environmental effects. But diets are unlikely to change overnight. Meanwhile, improved manure management can reduce nutrient loads to the Baltic Sea, writes Baltic Eye researcher Michelle McCrackin

As part of the ”Hållbar livsmedelskedja” (sustainable food chain) initiative, two of the largest supermarkets in Sweden – Coop and ICA – has recently started raising consumer awareness about the environmental impact of meat production. In costly ad campains they   promote vegetarian alternatives and urge their customers to eat less meat – for the sake of the environment.

Industrial meat production has negative consequences for the environment, including soil, water and air pollution and greenhouse gas emissions. As a result, there is public discussion in Europe and North America about the need to reduce meat consumption.

One person’s dietary decisions won’t have much effect on the environment, but widespread adoption of “reducetarian” or “climatarian” diets could achieve positive benefits. For example, a scientific study found that reducing in the consumption of meat, dairy products, and eggs in the EU by half could reduce nitrate emissions to groundwater and surface water by 40%. Another study found that reduced meat consumption (similar to a “Mediterranean diet”) could reduce eutrophication across the EU by 6-7%.

pig slaughtering schedule

                                                                                 Image: Messer Woland, based on Rainer Zenzs graphik

 

Diets aren’t likely to change anytime soon, however, unless there is greater public awareness of the environmental impact of meat production - and governments much more actively promote environmentally friendly diets. Unfortunately, the latter still seems far from being realized, at least in Europe. The EU Commissioner for Agriculture and Rural Development, Paul Hogan, recently spoke at a livestock summit in France, and pledged to provide an additional €15 million a year to be spent on the promotion of meat consumption throughout Europe.

Because diets are unlikely to change dramatically over night and because there is still a lack of political consensus, other measures have to be considered in order to mitigate the negative environmental effects of livestock production.

One short-term solution to protect the environment is to improve how manure is stored, handled, and recycled. Raising large numbers of animals in confined areas can create nutrient imbalances when the amount of nutrients in manure are greater than the needs of nearby cropland. Because manure is bulky, it is not economical to transport it over long distances. These nutrient imbalances increase the likelihood of leaching losses to groundwater and surface waters, especially in areas with high nutrient content in soils.

Around the Baltic Sea, A recent scientific study found that manure contributes 17% of nitrogen and 12% of phosphorus to the Baltic Sea. livestock produce about 2 million tons of nitrogen and 0.4 million tons of phosphorous in manure annually. This is 2-3 times more nitrogen and phosphorus than in the total amount of human excreta that comes from household wastewater in the Baltic Sea catchment area!

 it could be possible to reduce phosphorus loads by 1 500 tons

My own back-of-the-envelope estimate of the effect of improved manure recycling, shows that if 25% of mineral phosphorus fertilizers are replaced with already available manure nutrients in the region that drains to the Baltic Proper, it could be possible to reduce phosphorus loads by 1 500 tons. While this estimate is rough, it shows one path of progress towards the goals of the HELCOM Baltic Sea Action Plan.

To be able to use manure more efficient and thereby reduce the need for mineral fertilizers will require investment in new buildings and equipment to store, process, and transport manure. Another solution is to change how we produce meat. For example, better matching the number of livestock in an area with local crop needs by reducing the number of livestock per area could reduce nutrient imbalances. Also, the proposed EU regulation on fertilizer trade can become an important tool for recycling available nutrients in manure.

So, while waiting for the Europeans to change their dietary habits, a manure “diet” in agriculture could help the environment. 

Michelle McCrackin

Michelle McCrackin

Limnologist
michelle.mccrackin@su.se