Paper: Food consumption, diet shifts and associated non-CO2 greenhouse gases from agricultural production

 Citation 

Popp A, Lotze-Campen H and Bodirsky B (2010). Food consumption, diet shifts and associated non-CO₂ greenhouse gases from agricultural production, Global Environmental Change 20, 451–462

Abstract

Today, the agricultural sector accounts for approximately 15% of total global anthropogenic emissions, mainly methane and nitrous oxide. Projecting the future development of agricultural non-CO₂ greenhouse gas (GHG) emissions is important to assess their impacts on the climate system but poses many problems as future demand of agricultural products is highly uncertain.We developed a global land use model (MAgPIE) that is suited to assess future anthropogenic agricultural non-CO₂ GHG emissions from various agricultural activities by combining socio-economic information on population, income, food demand, and production costs with spatially explicit environmental data on potential crop yields. In this article we describe how agricultural non-CO₂ GHG emissions are implemented within MAgPIE and compare our simulation results with other studies. Furthermore, we apply the model up to 2055 to assess the impact of future changes in food consumption and diet shifts, but also of technological mitigation options on agricultural non-CO₂ GHG emissions. As a result, we found that global agricultural non-CO₂ emissions increase significantly until 2055 if food energy consumption and diet preferences remain constant at the level of 1995. Non-CO₂ GHG emissions will rise even more if increasing food energy consumption and changing dietary preferences towards higher value foods, like meat and milk, with increasing income are taken into account. In contrast, under a scenario of reduced meat consumption, non-CO₂ GHG emissions would decrease even compared to 1995. Technological mitigation options in the agricultural sector have also the capability of decreasing non-CO₂ GHG emissions significantly. However, these technological mitigation options are not as effective as changes in food consumption. Highest reduction potentials will be achieved by a combination of both approaches. 

In more detail: The authors consider 3 scenarios:

1. In the ‘baseline scenario’ regional trade balances, food energy demand and the share of livestock products in total caloric intake are kept constant at 1995 levels.
2. In the ‘increased meat scenario’ the link between GDP and food energy demand as well as the share of livestock products in total caloric intake are given by a regression equation (which is presented in a figure in the paper).
3. In the decreased meat scenario’ food energy increases with increasing GDP comparable to the ‘Increased meat scenario’ but the share of livestock products in total caloric intake is reduced in each time step, starting in 2005, by 25% compared to the previous time step.

The authors also developed the following additional 2 scenarios: 

• Increased meat scenario + technical mitigation’
• Decreased meat scenario + technical mitigation’ that consider technological mitigation options for all agricultural activities.

Regionally specific emission reduction factors are based on a study which the authors cite that investigates agricultural non-CO₂ reduction potential at different carbon prices. A carbon price of up to $1000 was used.

The study finds that:

• In the baseline scenario non CO₂ emissions rise from 5314 CO₂-e in 1995 to 8690 CO₂-e in 2055.
• In the increased meat scenario’ non CO₂ GHGs rise by 76% by 2050 compared with the baseline scenario.
• In the decreased meat scenario emissions drop by 51% compared to the baseline model.
• In the Increased meat scenario + technical mitigation, technological mitigation options in the agricultural sector decrease global agricultural non-CO₂ emissions by 36% in 2055, compared to the ‘increased meat scenario’, but still increase emissions by 13% compared to the ‘baseline scenario’.
• Lowest non-CO₂ emissions can be found in the ‘decreased meat scenario + technical mitigation’ where reduced demand for meat products combined with mitigation options in the agricultural sector will lead to global agricultural non-CO₂ emissions of 2519 CO₂-e in 2055 – i.e. an approximate halving of 1995 emissions.

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