Global environmental costs of China's thirst for milk
Global environmental costs of China's thirst for milk
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DOI：
10.1111/gcb.14047
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发表时间：
2018-05-01
影响因子：
11.6
通讯作者：
Zhang, Fusuo
中科院分区：
文献类型：
--
作者：
Bai, Zhaohai;Lee, Michael R. F.;Zhang, Fusuo
中国对牛奶的需求不断增加，预计到2050年，需求量将比2010年的产量增加3.2倍。满足这一需求的环境影响是什么，首选的途径是什么？我们通过使用一种关联方法来解决这些问题，以研究在国内牛奶生产和进口的不同情景下，到2050年中国牛奶消费量增加的相互依赖性及其全球影响。在一切照旧的情况下满足中国的牛奶需求将增加全球乳制品相关的（中国和主要牛奶出口地区）温室气体（GHG）排放量减少35%（从565到764 Tg CO2当量）和用于奶牛饲料生产的土地使用减少32%与2010年相比，乳制品行业的活性氮损失将增加48%（从3.6到5.4Tg氮）。用现有技术在中国生产所有额外的牛奶将大大增加动物饲料进口;精料从1.9 Tg增加到8.5 Tg，饲料（苜蓿）从1.0 Tg增加到6.2 Tg。此外，与2010年水平相比，国内乳制品相关的温室气体排放量将增加2.2倍。额外的牛奶将把环境负担从中国转移到牛奶出口国;由于物理限制或环境偏好/立法，目前的牛奶出口国可能无法生产所有额外的牛奶。例如，新西兰用于牛饲料生产的农田面积必须增加57%以上（130万公顷），欧洲必须增加39%以上（1500万公顷），而温室气体排放和氮损失将随着这两个地区农田面积的增加而大致成比例地增加。我们认为，一个更可持续的乳制品未来将依赖于高牛奶需求地区（如中国）将其国内牛奶和饲料生产效率提高到领先牛奶生产国的水平。这将使全球乳制品相关的温室气体排放量和土地使用量分别减少12%（减少90 Tg CO2当量）和30%（减少3400万公顷土地）。然而，与二零一零年的水平相比，这仍然意味着温室气体排放总量增加19%，而土地使用量将减少8%。
China has an ever-increasing thirst for milk, with a predicted 3.2-fold increase in demand by 2050 compared to the production level in 2010. What are the environmental implications of meeting this demand, and what is the preferred pathway? We addressed these questions by using a nexus approach, to examine the interdependencies of increasing milk consumption in China by 2050 and its global impacts, under different scenarios of domestic milk production and importation. Meeting China's milk demand in a business as usual scenario will increase global dairy-related (China and the leading milk exporting regions) greenhouse gas (GHG) emissions by 35% (from 565 to 764Tg CO2eq) and land use for dairy feed production by 32% (from 84 to 111 million ha) compared to 2010, while reactive nitrogen losses from the dairy sector will increase by 48% (from 3.6 to 5.4Tg nitrogen). Producing all additional milk in China with current technology will greatly increase animal feed import; from 1.9 to 8.5Tg for concentrates and from 1.0 to 6.2Tg for forage (alfalfa). In addition, it will increase domestic dairy related GHG emissions by 2.2 times compared to 2010 levels. Importing the extra milk will transfer the environmental burden from China to milk exporting countries; current dairy exporting countries may be unable to produce all additional milk due to physical limitations or environmental preferences/legislation. For example, the farmland area for cattle-feed production in New Zealand would have to increase by more than 57% (1.3 million ha) and that in Europe by more than 39% (15 million ha), while GHG emissions and nitrogen losses would increase roughly proportionally with the increase of farmland in both regions. We propose that a more sustainable dairy future will rely on high milk demanding regions (such as China) improving their domestic milk and feed production efficiencies up to the level of leading milk producing countries. This will decrease the global dairy related GHG emissions and land use by 12% (90Tg CO2eq reduction) and 30% (34 million ha land reduction) compared to the business as usual scenario, respectively. However, this still represents an increase in total GHG emissions of 19% whereas land use will decrease by 8% when compared with 2010 levels, respectively.