| Changes in the structure of food production and consumption have an important impact on the environment and human health.In addition to the environmental impact of food production and consumption,if a region has a small amount of food production and relies on imports,the environmental load generated by the food consumed during its production process will remain in the food production area.This article takes Jiangsu Province as the research object,constructs the relationship between food production and consumption-environment-ecological compensation,and seeks the sustainable development path of regional food production and consumption.On the basis of analyzing the characteristics of food production and consumption changes,firstly,life cycle assessment(LCA)is used to calculate the carbon emission in the food production and consumption system;secondly,according to the law of conservation of quality,the material flow analysis method(MFA)is used to establish regional food production Nitrogen and phosphorus flow model in the consumption system to calculate and analyze the change characteristics of nitrogen and phosphorus flux and its environmental load;finally,based on the relationship between food demand and carbon,nitrogen and phosphorus emissions involved in food consumption in Jiangsu Province,discuss the implementation of production compensation related to regional food consumption The feasibility and method of the mechanism.This research can provide a scientific basis for formulating reasonable sustainable food production and consumption strategies in the region,and has important practical significance for promoting regional ecological and environmental protection.Research indicates:(1)From 1990 to 2019,the total food production in Jiangsu Province increased from 63,256,600 tons to 106,264,300 tons.The output of grains,vegetables,fruits,aquatic products,eggs and dairy products all showed a fluctuating upward trend.Among them,the output of grain increased from 32.641 million tons to 37.062million tons,the output of vegetables increased from 25.942 million tons to 56.436million tons,and the output of fruits increased.553.23%,the output of aquatic products increased by 307.24%,the output of eggs increased by 139.01%,and the output of dairy products increased by nearly seven times.The output of vegetable oil,pork,and beef and mutton showed a trend of first increasing and then decreasing.During the period,the total per capita food consumption of urban residents decreased from 331.92 kg·a-1to 289.06 kg·a-1.In the food consumption structure in 1990,plant foods accounted for 87.08%and animal foods accounted for12.92%.In 2019,the two accounted for 75.19%and 24.81%respectively.The total per capita food consumption in rural areas decreased from 434.80 kg·a-1to 335.86kg·a-1.The proportion of plant food consumption decreased from 95.42%to 83.64%,and the consumption of animal food increased from 4.58%to 16.36%.The changes in the food consumption structure of urban and rural residents are manifested as a decrease in the proportion of plant food consumption and an increase in the proportion of animal food consumption.(2)The per capita carbon emission generated by the food production system in Jiangsu Province reached 1316.29 kg CO2·a-1in 2019,which was nearly double that of 1990.Among them,the direct carbon emission increased by 78.00%compared with 1990.The carbon emission in the production stage was reduced from 167.10kg CO2·a-1to 151.15 kg CO2·a-1.The carbon emission in the processing stage occupies the smallest proportion in the food production system.The carbon emission in the food transportation phase increased from 335.38 kg CO2·a-1in 1990 to 881.22kg CO2·a-1in 2019,accounting for 66.95%of the carbon emission of the production system,and contributing the most to the increase in per capita carbon emission.During the food consumption system,the per capita carbon emission decreased from725.59 kg CO2·a-1in 1990 to 495.30 kg CO2·a-1in 2019,and the direct carbon emission from per capita food consumption was reduced from 356.67 kg CO2·a-1in1990 to 202.91 kg CO2·a-1,the direct carbon emission of plant food consumption decreased by 55.44%,and the direct carbon emission of animal food consumption increased by 128.19%.The direct carbon emission of food consumption accounts for the largest proportion of the total per capita carbon emission of food consumption,about 45%.The per capita carbon emission in the food cooking stage is the second,and the per capita carbon emission in the food storage stage is the least.(3)From 1990 to 2019,the total nitrogen environmental load and per capita nitrogen environmental load of Jiangsu Province during the food production stage both increased first and then decreased.The total environmental load of nitrogen increased from 644,700 tons in 1990 to 1.0639 million tons in 2003.,and then dropped to 627,500 tons in 2019;the per capita nitrogen environmental load increased from 9.53 kg in 1990 to 14.27 kg in 2003;and then fell to 7.78 kg in 2019.The environmental load of food consumption nitrogen decreased from 321.16 Gg·a-1to 241.35 Gg·a-1.Among them,the environmental load of nitrogen entering the soil accounted for the highest proportion,increasing from 38.28%to 40.76%,those entering the atmosphere dropped from 33.63%to 32.34%,and those entering water bodies dropped from 28.09%to 26.90%..(4)The total phosphorus environmental load during the food production stage in Jiangsu Province from 1990 to 2019 showed an"M"-shaped change trend.From1990 to 2001,it increased from 331,400 tons to 594,400 tons,fell to 579.8 tons in2007,increased to a maximum of 607,600 tons in 2011,and then dropped to492,500 tons in 2019.The phosphorus environmental load of crop production has always dominated,reaching 470,500 tons in 2019,an increase of 59.73%over 1990,while the phosphorus environmental load of livestock and poultry breeding decreased by 40.33%.The environmental load of phosphorus in food consumption decreased from 20.21 Gg·a-1in 1990 to 18.17 Gg·a-1in 2019.The proportion of environmental load of phosphorus entering the soil has continuously increased from60.73%to 63.76%,while the proportion of environmental load of phosphorus in water bodies has dropped from 39.27%to 36.24%.(5)The total external carbon emission generated by the difference between food production and consumption in Jiangsu Province presents input-type carbon emission characteristics,and gradually fluctuated and declined,from 2,201,500 tons in 1990 to 13,702,900 tons in 2019..The total external nitrogen and phosphorus environmental load showed a trend of first increasing and then decreasing.The nitrogen environmental load increased from 239,500 tons in 1990 to 570,000 tons in2003,and then decreased to 281,400 tons in 2019.The environmental load of phosphorus increased from 268,100 tons in 1990 to 537,700 tons in 2011,and decreased to 392,100 tons in 2019.(6)The amount of ecological compensation for the food system in Jiangsu Province from 1990 to 2019 is positively correlated with its external environmental load.Carbon,nitrogen and phosphorus in Jiangsu Province have been in a state of compensation.The amount of carbon offset decreased from 1.031 billion yuan in1990 to 699 million yuan in 2019..The nitrogen compensation amount reached the maximum value of 4.560 billion yuan in 2003,and then slowly decreased,reaching2.251 billion yuan in 2019.The total amount of phosphorus compensation is divided into three stages.The first stage is from 1990 to 1999,and the amount of phosphorus compensation continues to grow,reaching 38.727 billion yuan in 1999;the second stage is from 1999 to 2015,and the amount of phosphorus compensation is in a stable state,basically maintained at around 40 billion yuan;the third stage is2015-2019,the amount of phosphorus compensation is slowly reduced,reaching31.371 billion yuan in 2019.(7)In order to promote the sustainable development of food production and consumption,Jiangsu Province should vigorously develop green agriculture,reduce the application of chemical fertilizers and pesticides to reduce the environmental load of nitrogen and phosphorus;encourage the production and consumption of food nearby to reduce the carbon emission of the transportation stage of the food system;Encourage the increase of plant-based diets and the reduction of animal-based diets to reduce the increase in carbon environmental load caused by poor dietary structure;establish an ecological compensation mechanism for food production and consumption to promote the coordinated development of the regional environment. |
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