Meat Production at the Root of Climate Change and Food Insecurity
Meat production has quadrupled in the past 50 years, and is expected to further increase by 20% in 2030. Silently, this industry may have been shaping a dangerous future.
In 2006, the FAO estimated that livestock production was responsible for 18% of the world's GHG emissions. However, a later report by WorldWatch, in 2009, considered this value to be very underestimated, as numerous factors had been overlooked and the statistics used were out-dated. The latter model concluded that animal production is responsible for a staggering 51% of the global GHG emissions, making livestock the single most important driver of climate change.
Livestock production mainly releases methane (CH4) from the digestive process (enteric fermentation) of ruminants (e.g. cattle, goats, sheep) and their manure, and the latter is also a source of nitrous oxide (N2O). While the amount of these gases in the atmosphere is minimal compared to CO2, their global-warming potential (how much heat they capture from solar radiation) is much higher: in their first 20 years in the atmosphere, CH4 absorbs 56 times more heat than CO2, and 280 times more heat is captured by N2O. Yet, CH4 degrades and disappears much faster from the atmosphere than CO2. Mitigating it can therefore rapidly limit the greenhouse effect, and it is urgent in order to keep the global temperature increase below 2ºC in the coming decade.
The respiration of livestock also releases CO2, which would normally be in balance with the C sequestration of lands, but this balance has been broken by the enormity of the current population of market animals: about 1.4 billion cattle, 1.9 billion sheep and goats, 1 billion pigs and 19.6 billion chickens; this factor was overlooked by the FAO.
Last, the conversion of lands into pasture for grazing and into croplands to grow livestock feed also contributes a significant share of livestock's emissions, and the forests that have been lost to livestock expansion have lost their C sequestration potential.
In 2006, the FAO estimated that livestock production was responsible for 18% of the world's GHG emissions. However, a later report by WorldWatch, in 2009, considered this value to be very underestimated, as numerous factors had been overlooked and the statistics used were out-dated. The latter model concluded that animal production is responsible for a staggering 51% of the global GHG emissions, making livestock the single most important driver of climate change.
Livestock production mainly releases methane (CH4) from the digestive process (enteric fermentation) of ruminants (e.g. cattle, goats, sheep) and their manure, and the latter is also a source of nitrous oxide (N2O). While the amount of these gases in the atmosphere is minimal compared to CO2, their global-warming potential (how much heat they capture from solar radiation) is much higher: in their first 20 years in the atmosphere, CH4 absorbs 56 times more heat than CO2, and 280 times more heat is captured by N2O. Yet, CH4 degrades and disappears much faster from the atmosphere than CO2. Mitigating it can therefore rapidly limit the greenhouse effect, and it is urgent in order to keep the global temperature increase below 2ºC in the coming decade.
The respiration of livestock also releases CO2, which would normally be in balance with the C sequestration of lands, but this balance has been broken by the enormity of the current population of market animals: about 1.4 billion cattle, 1.9 billion sheep and goats, 1 billion pigs and 19.6 billion chickens; this factor was overlooked by the FAO.
Last, the conversion of lands into pasture for grazing and into croplands to grow livestock feed also contributes a significant share of livestock's emissions, and the forests that have been lost to livestock expansion have lost their C sequestration potential.
CO2-equivalent emissions by livestock species: beef is by far the most polluting type of meat (FAO).
Another major problem of animal agriculture is that it is a very inefficient use of land and resources compared to growing crops directly for human consumption, and therefore it is a major driver of global food insecurity. For instance, it takes over 100 times more land to produce 1g of protein from beef than from pulses or maize (Figure 1). Also, over 1/3 of the grain produced and 1/3 of the fish caught worldwide are fed to livestock, and most of the calories fed to livestock are lost in their conversion to meat calories (Figure 2).
Figure 1 - Land required to produce 1g of protein with different meat and crop types.
Figure 2 - Calories conserved in meat from the calories fed to livestock (energy efficiency).
Croplands used to produce directly for human consumption occupy only 22% of the world's agricultural lands (Figure 3). If all these lands were used exclusively for direct human consumption, about 70% more food calories would be available for humans, allowing to feed an extra 4 billion people (over half of the current world population). I believe that this situation deserves a spotlight, and correcting it needs to be a priority in a world where over 815 million people still suffer from malnutrition.
Figure 3 - Share of the world's agricultural lands in 2009 (adapted from Boucher 2012).
However, in some specific areas of the world where food insecurity is paramount, such as parts of Sub-Saharan Africa and South East Asia, lands are not productive enough for growing crops, and they rely on livestock as their main nutritional source. In these places, livestock production is the most efficient use of the lands for food, and it is carried out at small scales and not replacing other ecosystems. The animal production that is most damaging is the large-scale commercial livestock industry that has expanded across natural environments to supply the excessive meat demand from rich and growing nations.
A global shift towards a plant-based diet may hence be central to quickly mitigating climate change and ensuring enough food to satisfy a growing demand. However, a plant-based diet is not completely harmless to the environment either, as producing some vegetables and fruits is also C and resource-intensive, and a thoughtful combination of plant products must be favored over others. Restricting the calorie intake per capita in rich countries may additionally reduce the global impact of food production and improve food security, therefore a transition towards a low-calorie, plant-based diet may be an important part of the solution to rapidly mitigating climate change and ending global hunger.
Diego Garcia-Vega - October 20th 2017
A global shift towards a plant-based diet may hence be central to quickly mitigating climate change and ensuring enough food to satisfy a growing demand. However, a plant-based diet is not completely harmless to the environment either, as producing some vegetables and fruits is also C and resource-intensive, and a thoughtful combination of plant products must be favored over others. Restricting the calorie intake per capita in rich countries may additionally reduce the global impact of food production and improve food security, therefore a transition towards a low-calorie, plant-based diet may be an important part of the solution to rapidly mitigating climate change and ending global hunger.
Diego Garcia-Vega - October 20th 2017