Global Dairy GHG Emissions Are Rising—and Falling
It sounds like a contradiction of terms. Total greenhouse gas (GHG) emissions from the dairy industry continue to rise as world milk production increases to feed a hungry planet. At the same time, GHG emissions per gallon of milk have fallen, thanks to more milk per cow and greater feed efficiency.
The Food and Agriculture Organization (FAO) of the United Nations estimates global GHG emissions from the dairy industry totaled 1,712 million metric tons of CO₂ equivalent, or about 3% of total world emissions, in 2015. FAO estimates that total GHG emissions from the dairy sector increased 18% from 2005 to 2015.
But at the same time, global milk production increased an astounding 30%. While the dairy herd increased 11%, milk production per cow increased 15%. The result: GHG emissions per kilogram of milk produced decreased 11%, or about 1% per year.
“Without gains in productivity (and assuming production grew at the same rate), to deliver the same amount of product, total emissions would have increased by approximately 38% rather than 18% between 2005 and 2015,” says the FAO report.
The FAO report also lays out the daunting challenge of reducing GHGs across the globe. World population is expected to grow to 8.6 billion people by 2030, a 13% increase from today’s population of 7.6 billion. By 2050, world population is expected to approach 10 billion.
“More than 80 percent of the world’s population, or about 6 billion people, regularly consume liquid milk or other dairy products,” says the FAO report.
At the same time, FAO notes that dairy products are nutrient dense foods, supplying significant amounts of energy, protein and micronutrients, including calcium, magnesium, selenium, riboflavin, and vitamins B5 and B12. “[Dairy products] are the fifth largest provider of energy and the third largest provider of protein and fat for human beings and an important source of affordable nutrition to meet recommended levels,” says the FAO report.
Plus, dairy farming is integral to the economies of many countries. There are about 133 million farmers with dairy cattle word wide, including 80 million women who are engaged in dairy farming, at least to some extent.
The implied consequence: Eliminating dairy cows and dairy farming from the planet would be highly disruptive to the world’s food supply and economic and social structure.
The other take home message is that production efficiency really matters when it comes to GHG emissions. North American dairy cattle have the highest GHG emissions per animal in the world. But because they have the highest milk output as well, their GHG emissions per kilogram of milk produced is the envy of the world.
The global average GHG emission in terms of kilograms of CO₂eq/kg of corrected fat and protein milk is 2.5. In North America, the GHG emission is 1.29, or nearly 50% less than the global average. Oceania (New Zealand and Australia) are the second lowest GHG emitters per kilogram of milk produced at 1.31. Western Europe comes in third, at 1.37. In contrast, the least efficient is Sub-Sahara Africa, at 6.67. See table.
Reducing GHG emissions at the farm level boils down to feed, manure and fertilizer management, energy use and animal health and husbandry, says the FAO report.
“The scope to make large reductions in the total emissions from the dairy sector without compromising output is limited. Reducing absolute emissions will require a combination of constraining production (appreciating that this would be challenging with increasing consumer demand) and achieving significant breakthroughs in developing new mitigation technologies and strategies…. However, in high-income countries, waste at the consumption level makes up the largest proportion of total loss and waste.”
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Table: GHG emissions and milk production
Country Milk/cow (kg) Maintenance Methane/cow* CO₂eq/kg of milk
North America 9,867 39 117 1.29
Russia 4,146 50 72 1.39
Western Europe 6,957 42 81 1.37
Eastern Europe 5,005 47 82 1.34
North Africa 1,830 62 73 4.41
East Asia 2,907 53 69 2.43
Oceania 4,659 43 81 1.31
South Asia 1,388 65 62 4.10
America 1,947 63 85 3.36
Sub-Sahara Africa 457 75 46 6.67
*Kg of CH4/animal