Study On The Carbon Footprint Of Chinese Food Consumption In The Context Of Urbanization

In the context of climate change,the issue of greenhouse gas emissions caused by food consumption has received considerable academic attention.Urbanization has promoted the overall evolution of urban residential dietary structure,dining location,and patterns of population migration in China,which in turn affects greenhouse gas emissions and climate change resulting from food consumption.Regarding to the problems above,this dissertation focuses on the issues of the greenhouse gas emissions resulting from Chinese dietary habits like eating at home(EAH),eating away from home(EAFH),and food consumption of the floating population.Methods of Monte Carlo simulation,statistical regression and difference test,Bayesian model,Remote sensing and GIS spatial analysis methods,etc.were included to quantify the impacts of urbanization on the dietary patterns and greenhouse gas emissions(carbon footprint,i.e.,CF)of residents,and reveal the driving mechanism of changes in CF of food consumption,and further investigate the coupled effect of population migration and geographically varied dietary patterns on greenhouse gas emissions.This thesis provides a reference for sustainable consumption of food and mitigation of climate change in China The main research contents and results are as follows:(1)The temporal and spatial changes in CF of food consumption at home were quantified and analyzed by using the data of the residents’ dietary survey and the CF parameters of LCA-based literature.The inter-relationship between urbanization,food accessibility,and CF of EAH was determined through a case study.The results showed that the average dietary CF increased from 3,063 g CO2e cap-1 d-1 to 3,365 g CO2e cap-1 d-1,and the consumption of animal products increased by 26%,while plant-based foods decreased by 3%from 2004 to 2011.The range of variation in CF of EAH in 12 surveyed provinces was from 2,210 to 4,443 g CO2e cap-1 d-1.The provincial per capita consumption of animal products(163 g cap-1d-1)only accounted for 15%of the total grams of food consumed at home,but its CF accounted for 36%of the total dietary CF.There were significant differences in the influence of different food accessibility on the consumption of animal and plant-based foods(p<0.01).The CF of EAH decreased first and then increased with the increase of distance to the source of food.The case study showed that there were significant differences in the influence of different urbanization levels on spatial access to food(p<0.01).The spatial accessibility of various foods in highly urbanized communities was limited,but was optimal in communities with medium to low urbanization levels,within 4-9 minutes walking distance.(2)Urbanization levels were constructed based on survey data,and the influences of urbanization on CFs of EAH and EAFH were compared by regression analysis.The Bayesian Belief Network model was developed to identify the key factors that affect EAFH.The results showed that food consumption away-from-home(948 g cap-1d-1)was less than at-home(1088 g cap-1 d-1)but its embedded CF was higher by 314 g CO2e cap-1 d-1.The influence of urbanization on the CF structures of EAH was higher than that of away-from-home,and the marginal effect of the ratio of animal/plant-based foods consumption CF of EAH was 1.3 times higher than that of EAFH.With the urbanization levels of communities ranging from lowest to highest,the CF of animal products consumed at home increased about 4-fold,and animal products consumed away from home more than 1-fold.The accuracy of the constructed Bayesian Belief Network model to predict the probability of EAFH for residents was 89%,and the results of sensitivity analysis showed that compared with the macro geographical factors,the individual factors of occupation and income were the key factors that affect EAFH for Chinese citizens.(3)The changes in the CFs of the interprovincial floating population caused by dietary acculturation were measured based on the data of dietary structure difference and floating population between provinces.The regression models were constructed to reveal the influences of economic factors on the changes in dietary CFs of the floating population and the association between the virtual dietary carbon flows and virtual environmental impacts of regional commodity trades in China.The results showed that the consumption of animal products of residents in southern provinces of China was significantly higher than that in northern provinces(p<0.01),and the difference in dietary structure between urban and rural residents in southern provinces was less than that in northern provinces.The dietary acculturation of interprovincial floating population led to an increase in dietary CF by 21 Mt CO2e yr-1 on average in China.Approximately 74%of this net CF increase was concentrated in the five coastal provinces of southern China.The increased intakes of aquatic products and beef jointly contributed 75%of this CF growth,while declined cereal intake offset CF increase by 44%.Compared to per capita disposable income,the Engel coefficient was more powerful to explain the dietary CF variations of the floating population,revealing that every 1%change in the difference between the interprovincial Engel coefficients,the difference in the annual per capita CF of the floating population changed accordingly by 18-34 kg CO2e.Additionally,the changes of dietary CFs of the floating population were positively correlated with the implied environmental impacts of regional commodity trades in China,showing that the migrant flows and commodity trade flows were consistent in spatial directions.