Land-use competition and agricultural greenhouse gas emissions in a climate change mitigation perspective

Sammanfattning: Productive land for food production, bioenergy, or preservation of nature is a limited resource. Climate change mitigation puts additional pressure on land via higher demand for bioenergy to replace fossil fuels and via restrictions on deforestation—two processes that limit the availability of land for food produc- tion, and may thus also raise food prices. Methane and nitrous oxide emis- sions from agriculture may also need to be reduced to efficiently mitigate climate change. This thesis deals with this in three ways. In papers I–II, we estimate greenhouse gas emissions from food production for current diets and expected future developments, together with alternative di- etary developments and potential technical improvements in the agricultural sec- tor. Costs and possibilities for reaching climate goals are analyzed for the differ- ent diets. The results indicate that a phase out of ruminant products would cut mitigation cost in half, for staying below a 2◦C limit, and it may be necessary if the climate sensitivity is high. In papers III–IV, a conceptual and transparent partial equilibrium model of global land-use competition is developed, analyzed and applied. The model is to a large degree analytically explored and price differentials between crops are derived. The model is subjected to a detailed characterization of its mechanisms and parameters that are critical to the results. We conclude that the total amount of productive agricultural area and bioenergy yields are of crucial importance to the price impacts from large-scale introduction of bioenergy. We also show how limiting bioenergy production to marginal land could be difficult to implement in practice. In paper V, we use two established indicators for poverty and sensitivity to food-price changes to capture peoples’ vulnerability to rising food-prices in four Sub-Sahara African countries/regions. In contrast to previous studies, we include all food products instead of just one or a few main staples. We found that the vast majority of people are net consumers of food and that the inclusion of more than main staples increases their net position as consumers and thus vulnerability to high food prices.